Merge branch 'vb_treesupports'

src/clipper/clipper.cpp

@@ -602,9 +602,18 @@ bool HorzSegmentsOverlap(cInt seg1a, cInt seg1b, cInt seg2a, cInt seg2b)
 // ClipperBase class methods ...
 //------------------------------------------------------------------------------
 
-#ifndef CLIPPERLIB_INT32
+#ifdef CLIPPERLIB_INT32
+static inline void RangeTest(const IntPoint &pt)
+{
+#ifndef NDEBUG
+    static constexpr const int32_t hi = 65536 * 16383;
+    if (pt.x() > hi || pt.y() > hi || -pt.x() > hi || -pt.y() > hi) 
+      throw clipperException("Coordinate outside allowed range");
+#endif // NDEBUG
+}
+#else // CLIPPERLIB_INT32
 // Called from ClipperBase::AddPath() to verify the scale of the input polygon coordinates.
-inline void RangeTest(const IntPoint& Pt, bool& useFullRange)
+static inline void RangeTest(const IntPoint& Pt, bool& useFullRange)
 {
   if (useFullRange)
   {
@@ -798,7 +807,10 @@ bool ClipperBase::AddPathInternal(const Path &pg, int highI, PolyType PolyTyp, b
   try
   {
     edges[1].Curr = pg[1];
-#ifndef CLIPPERLIB_INT32
+#ifdef CLIPPERLIB_INT32
+    RangeTest(pg[0]);
+    RangeTest(pg[highI]);
+#else
     RangeTest(pg[0], m_UseFullRange);
     RangeTest(pg[highI], m_UseFullRange);
 #endif // CLIPPERLIB_INT32
@@ -806,7 +818,9 @@ bool ClipperBase::AddPathInternal(const Path &pg, int highI, PolyType PolyTyp, b
     InitEdge(&edges[highI], &edges[0], &edges[highI-1], pg[highI]);
     for (int i = highI - 1; i >= 1; --i)
     {
-#ifndef CLIPPERLIB_INT32
+#ifdef CLIPPERLIB_INT32
+      RangeTest(pg[i]);
+#else
       RangeTest(pg[i], m_UseFullRange);
 #endif // CLIPPERLIB_INT32
       InitEdge(&edges[i], &edges[i+1], &edges[i-1], pg[i]);

src/libslic3r/BoundingBox.hpp

@@ -18,7 +18,7 @@ public:
     
     BoundingBoxBase() : min(PointClass::Zero()), max(PointClass::Zero()), defined(false) {}
     BoundingBoxBase(const PointClass &pmin, const PointClass &pmax) : 
-        min(pmin), max(pmax), defined(pmin(0) < pmax(0) && pmin(1) < pmax(1)) {}
+        min(pmin), max(pmax), defined(pmin.x() < pmax.x() && pmin.y() < pmax.y()) {}
     BoundingBoxBase(const PointClass &p1, const PointClass &p2, const PointClass &p3) :
         min(p1), max(p1), defined(false) { merge(p2); merge(p3); }
 
@@ -37,7 +37,7 @@ public:
                 this->min = this->min.cwiseMin(vec);
                 this->max = this->max.cwiseMax(vec);
             }
-            this->defined = (this->min(0) < this->max(0)) && (this->min(1) < this->max(1));
+            this->defined = (this->min.x() < this->max.x()) && (this->min.y() < this->max.y());
         }
     }
 
@@ -58,15 +58,15 @@ public:
     BoundingBoxBase<PointClass> inflated(coordf_t delta) const throw() { BoundingBoxBase<PointClass> out(*this); out.offset(delta); return out; }
     PointClass center() const;
     bool contains(const PointClass &point) const {
-        return point(0) >= this->min(0) && point(0) <= this->max(0)
+        return point.x() >= this->min.x() && point.x() <= this->max.x()
-            && point(1) >= this->min(1) && point(1) <= this->max(1);
+            && point.y() >= this->min.y() && point.y() <= this->max.y();
     }
     bool contains(const BoundingBoxBase<PointClass> &other) const {
         return contains(other.min) && contains(other.max);
     }
     bool overlap(const BoundingBoxBase<PointClass> &other) const {
-        return ! (this->max(0) < other.min(0) || this->min(0) > other.max(0) ||
+        return ! (this->max.x() < other.min.x() || this->min.x() > other.max.x() ||
-                  this->max(1) < other.min(1) || this->min(1) > other.max(1));
+                  this->max.y() < other.min.y() || this->min.y() > other.max.y());
     }
     bool operator==(const BoundingBoxBase<PointClass> &rhs) { return this->min == rhs.min && this->max == rhs.max; }
     bool operator!=(const BoundingBoxBase<PointClass> &rhs) { return ! (*this == rhs); }
@@ -79,7 +79,7 @@ public:
     BoundingBox3Base() : BoundingBoxBase<PointClass>() {}
     BoundingBox3Base(const PointClass &pmin, const PointClass &pmax) : 
         BoundingBoxBase<PointClass>(pmin, pmax) 
-        { if (pmin(2) >= pmax(2)) BoundingBoxBase<PointClass>::defined = false; }
+        { if (pmin.z() >= pmax.z()) BoundingBoxBase<PointClass>::defined = false; }
     BoundingBox3Base(const PointClass &p1, const PointClass &p2, const PointClass &p3) :
         BoundingBoxBase<PointClass>(p1, p1) { merge(p2); merge(p3); }
 
@@ -96,7 +96,7 @@ public:
             this->min = this->min.cwiseMin(vec);
             this->max = this->max.cwiseMax(vec);
         }
-        this->defined = (this->min(0) < this->max(0)) && (this->min(1) < this->max(1)) && (this->min(2) < this->max(2));
+        this->defined = (this->min.x() < this->max.x()) && (this->min.y() < this->max.y()) && (this->min.z() < this->max.z());
     }
 
     BoundingBox3Base(const std::vector<PointClass> &points)
@@ -116,15 +116,17 @@ public:
     coordf_t max_size() const;
 
     bool contains(const PointClass &point) const {
-        return BoundingBoxBase<PointClass>::contains(point) && point(2) >= this->min(2) && point(2) <= this->max(2);
+        return BoundingBoxBase<PointClass>::contains(point) && point.z() >= this->min.z() && point.z() <= this->max.z();
     }
 
     bool contains(const BoundingBox3Base<PointClass>& other) const {
         return contains(other.min) && contains(other.max);
     }
 
+    // Intersects without boundaries.
     bool intersects(const BoundingBox3Base<PointClass>& other) const {
-        return (this->min(0) < other.max(0)) && (this->max(0) > other.min(0)) && (this->min(1) < other.max(1)) && (this->max(1) > other.min(1)) && (this->min(2) < other.max(2)) && (this->max(2) > other.min(2));
+        return this->min.x() < other.max.x() && this->max.x() > other.min.x() && this->min.y() < other.max.y() && this->max.y() > other.min.y() && 
+            this->min.z() < other.max.z() && this->max.z() > other.min.z();
     }
 };
 
@@ -212,13 +214,13 @@ public:
 template<typename VT>
 inline bool empty(const BoundingBoxBase<VT> &bb)
 {
-    return ! bb.defined || bb.min(0) >= bb.max(0) || bb.min(1) >= bb.max(1);
+    return ! bb.defined || bb.min.x() >= bb.max.x() || bb.min.y() >= bb.max.y();
 }
 
 template<typename VT>
 inline bool empty(const BoundingBox3Base<VT> &bb)
 {
-    return ! bb.defined || bb.min(0) >= bb.max(0) || bb.min(1) >= bb.max(1) || bb.min(2) >= bb.max(2);
+    return ! bb.defined || bb.min.x() >= bb.max.x() || bb.min.y() >= bb.max.y() || bb.min.z() >= bb.max.z();
 }
 
 inline BoundingBox scaled(const BoundingBoxf &bb) { return {scaled(bb.min), scaled(bb.max)}; }

src/libslic3r/Brim.cpp

@@ -332,7 +332,7 @@ static std::vector<InnerBrimExPolygons> inner_brim_area(const Print
                 append(no_brim_area_object, diff_ex(offset(ex_poly.contour, no_brim_offset, ClipperLib::jtSquare), ex_poly_holes_reversed));
 
             if (brim_type == BrimType::btOuterOnly || brim_type == BrimType::btNoBrim)
-                append(no_brim_area_object, diff_ex(ExPolygon(ex_poly.contour), shrink_ex(ex_poly_holes_reversed, no_brim_offset, ClipperLib::jtSquare)));
+                append(no_brim_area_object, diff_ex(ex_poly.contour, shrink_ex(ex_poly_holes_reversed, no_brim_offset, ClipperLib::jtSquare)));
 
             append(holes_reversed_object, ex_poly_holes_reversed);
         }

src/libslic3r/CMakeLists.txt

@@ -256,6 +256,10 @@ set(SLIC3R_SOURCES
     Technologies.hpp
     Tesselate.cpp
     Tesselate.hpp
+    TreeSupport.cpp
+    TreeSupport.hpp
+    TreeModelVolumes.cpp
+    TreeModelVolumes.hpp
     TriangleMesh.cpp
     TriangleMesh.hpp
     TriangleMeshSlicer.cpp

src/libslic3r/ClipperUtils.cpp

@@ -556,6 +556,8 @@ Slic3r::Polygons diff(const Slic3r::Surfaces &subject, const Slic3r::Polygons &c
     { return _clipper(ClipperLib::ctDifference, ClipperUtils::SurfacesProvider(subject), ClipperUtils::PolygonsProvider(clip), do_safety_offset); }
 Slic3r::Polygons intersection(const Slic3r::Polygon &subject, const Slic3r::Polygon &clip, ApplySafetyOffset do_safety_offset)
     { return _clipper(ClipperLib::ctIntersection, ClipperUtils::SinglePathProvider(subject.points), ClipperUtils::SinglePathProvider(clip.points), do_safety_offset); }
+Slic3r::Polygons intersection(const Slic3r::Polygons &subject, const Slic3r::ExPolygon &clip, ApplySafetyOffset do_safety_offset)
+    { return _clipper(ClipperLib::ctIntersection, ClipperUtils::PolygonsProvider(subject), ClipperUtils::ExPolygonProvider(clip), do_safety_offset); }
 Slic3r::Polygons intersection(const Slic3r::Polygons &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset)
     { return _clipper(ClipperLib::ctIntersection, ClipperUtils::PolygonsProvider(subject), ClipperUtils::PolygonsProvider(clip), do_safety_offset); }
 Slic3r::Polygons intersection(const Slic3r::ExPolygon &subject, const Slic3r::ExPolygon &clip, ApplySafetyOffset do_safety_offset)
@@ -576,6 +578,8 @@ Slic3r::Polygons union_(const Slic3r::ExPolygons &subject)
     { return _clipper(ClipperLib::ctUnion, ClipperUtils::ExPolygonsProvider(subject), ClipperUtils::EmptyPathsProvider(), ApplySafetyOffset::No); }
 Slic3r::Polygons union_(const Slic3r::Polygons &subject, const Slic3r::Polygons &subject2)
     { return _clipper(ClipperLib::ctUnion, ClipperUtils::PolygonsProvider(subject), ClipperUtils::PolygonsProvider(subject2), ApplySafetyOffset::No); }
+Slic3r::Polygons union_(const Slic3r::Polygons &subject, const Slic3r::ExPolygon &subject2)
+    { return _clipper(ClipperLib::ctUnion, ClipperUtils::PolygonsProvider(subject), ClipperUtils::ExPolygonProvider(subject2), ApplySafetyOffset::No); }
 
 template <typename TSubject, typename TClip>
 static ExPolygons _clipper_ex(ClipperLib::ClipType clipType, TSubject &&subject,  TClip &&clip, ApplySafetyOffset do_safety_offset, ClipperLib::PolyFillType fill_type = ClipperLib::pftNonZero)
@@ -585,6 +589,8 @@ Slic3r::ExPolygons diff_ex(const Slic3r::Polygons &subject, const Slic3r::Polygo
     { return _clipper_ex(ClipperLib::ctDifference, ClipperUtils::PolygonsProvider(subject), ClipperUtils::PolygonsProvider(clip), do_safety_offset); }
 Slic3r::ExPolygons diff_ex(const Slic3r::Polygons &subject, const Slic3r::Surfaces &clip, ApplySafetyOffset do_safety_offset)
     { return _clipper_ex(ClipperLib::ctDifference, ClipperUtils::PolygonsProvider(subject), ClipperUtils::SurfacesProvider(clip), do_safety_offset); }
+Slic3r::ExPolygons diff_ex(const Slic3r::Polygon &subject, const Slic3r::ExPolygons &clip, ApplySafetyOffset do_safety_offset)
+    { return _clipper_ex(ClipperLib::ctDifference, ClipperUtils::SinglePathProvider(subject.points), ClipperUtils::ExPolygonsProvider(clip), do_safety_offset); }
 Slic3r::ExPolygons diff_ex(const Slic3r::Polygons &subject, const Slic3r::ExPolygons &clip, ApplySafetyOffset do_safety_offset)
     { return _clipper_ex(ClipperLib::ctDifference, ClipperUtils::PolygonsProvider(subject), ClipperUtils::ExPolygonsProvider(clip), do_safety_offset); }
 Slic3r::ExPolygons diff_ex(const Slic3r::ExPolygon &subject, const Slic3r::Polygon &clip, ApplySafetyOffset do_safety_offset)
@@ -715,6 +721,8 @@ Slic3r::Polylines diff_pl(const Slic3r::Polygons &subject, const Slic3r::Polygon
     { return _clipper_pl_closed(ClipperLib::ctDifference, ClipperUtils::PolygonsProvider(subject), ClipperUtils::PolygonsProvider(clip)); }
 Slic3r::Polylines intersection_pl(const Slic3r::Polylines &subject, const Slic3r::Polygon &clip)
     { return _clipper_pl_open(ClipperLib::ctIntersection, ClipperUtils::PolylinesProvider(subject), ClipperUtils::SinglePathProvider(clip.points)); }
+Slic3r::Polylines intersection_pl(const Slic3r::Polylines &subject, const Slic3r::ExPolygon &clip)
+    { return _clipper_pl_open(ClipperLib::ctIntersection, ClipperUtils::PolylinesProvider(subject), ClipperUtils::ExPolygonProvider(clip)); }
 Slic3r::Polylines intersection_pl(const Slic3r::Polyline &subject, const Slic3r::Polygons &clip)
     { return _clipper_pl_open(ClipperLib::ctIntersection, ClipperUtils::SinglePathProvider(subject.points), ClipperUtils::PolygonsProvider(clip)); }
 Slic3r::Polylines intersection_pl(const Slic3r::Polyline &subject, const Slic3r::ExPolygons &clip)

src/libslic3r/ClipperUtils.hpp

@@ -420,6 +420,7 @@ inline Slic3r::Lines diff_ln(const Slic3r::Lines &subject, const Slic3r::Polygon
 
 // Safety offset is applied to the clipping polygons only.
 Slic3r::Polygons   intersection(const Slic3r::Polygon &subject, const Slic3r::Polygon &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
+Slic3r::Polygons   intersection(const Slic3r::Polygons &subject, const Slic3r::ExPolygon &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
 Slic3r::Polygons   intersection(const Slic3r::Polygons &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
 Slic3r::Polygons   intersection(const Slic3r::ExPolygon &subject, const Slic3r::ExPolygon &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
 Slic3r::Polygons   intersection(const Slic3r::ExPolygons &subject, const Slic3r::Polygons &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
@@ -436,6 +437,7 @@ Slic3r::ExPolygons intersection_ex(const Slic3r::Surfaces &subject, const Slic3r
 Slic3r::ExPolygons intersection_ex(const Slic3r::Surfaces &subject, const Slic3r::Surfaces &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
 Slic3r::ExPolygons intersection_ex(const Slic3r::SurfacesPtr &subject, const Slic3r::ExPolygons &clip, ApplySafetyOffset do_safety_offset = ApplySafetyOffset::No);
 Slic3r::Polylines  intersection_pl(const Slic3r::Polylines &subject, const Slic3r::Polygon &clip);
+Slic3r::Polylines  intersection_pl(const Slic3r::Polylines &subject, const Slic3r::ExPolygon &clip);
 Slic3r::Polylines  intersection_pl(const Slic3r::Polyline &subject, const Slic3r::Polygons &clip);
 Slic3r::Polylines  intersection_pl(const Slic3r::Polyline &subject, const Slic3r::ExPolygons &clip);
 Slic3r::Polylines  intersection_pl(const Slic3r::Polylines &subject, const Slic3r::Polygons &clip);
@@ -458,6 +460,7 @@ Slic3r::Polygons union_(const Slic3r::Polygons &subject);
 Slic3r::Polygons union_(const Slic3r::ExPolygons &subject);
 Slic3r::Polygons union_(const Slic3r::Polygons &subject, const ClipperLib::PolyFillType fillType);
 Slic3r::Polygons union_(const Slic3r::Polygons &subject, const Slic3r::Polygons &subject2);
+Slic3r::Polygons union_(const Slic3r::Polygons &subject, const Slic3r::ExPolygon &subject2);
 // May be used to "heal" unusual models (3DLabPrints etc.) by providing fill_type (pftEvenOdd, pftNonZero, pftPositive, pftNegative).
 Slic3r::ExPolygons union_ex(const Slic3r::Polygons &subject, ClipperLib::PolyFillType fill_type = ClipperLib::pftNonZero);
 Slic3r::ExPolygons union_ex(const Slic3r::ExPolygons &subject);

src/libslic3r/ExPolygon.cpp

@@ -12,27 +12,6 @@
 
 namespace Slic3r {
 
-ExPolygon::operator Points() const
-{
-    Points points;
-    Polygons pp = *this;
-    for (Polygons::const_iterator poly = pp.begin(); poly != pp.end(); ++poly) {
-        for (Points::const_iterator point = poly->points.begin(); point != poly->points.end(); ++point)
-            points.push_back(*point);
-    }
-    return points;
-}
-
-ExPolygon::operator Polygons() const
-{
-    return to_polygons(*this);
-}
-
-ExPolygon::operator Polylines() const
-{
-    return to_polylines(*this);
-}
-
 void ExPolygon::scale(double factor)
 {
     contour.scale(factor);
@@ -149,7 +128,7 @@ bool ExPolygon::overlaps(const ExPolygon &other) const
     svg.draw_outline(*this);
     svg.draw_outline(other, "blue");
     #endif
-    Polylines pl_out = intersection_pl((Polylines)other, *this);
+    Polylines pl_out = intersection_pl(to_polylines(other), *this);
     #if 0
     svg.draw(pl_out, "red");
     #endif

src/libslic3r/ExPolygon.hpp

@@ -34,9 +34,6 @@ public:
     Polygon  contour;
     Polygons holes;
 
-    operator Points() const;
-    operator Polygons() const;
-    operator Polylines() const;
     void clear() { contour.points.clear(); holes.clear(); }
     void scale(double factor);
     void translate(double x, double y) { this->translate(Point(coord_t(x), coord_t(y))); }
@@ -281,6 +278,19 @@ inline ExPolygons to_expolygons(Polygons &&polys)
     return ex_polys;
 }
 
+inline Points to_points(const ExPolygon &expoly)
+{
+    size_t cnt = expoly.contour.size();
+    for (const Polygon &hole : expoly.holes)
+        cnt += hole.size();
+    Points out;
+    out.reserve(cnt);
+    append(out, expoly.contour.points);
+    for (const Polygon &hole : expoly.holes)
+        append(out, hole.points);
+    return out;
+}
+
 inline void polygons_append(Polygons &dst, const ExPolygon &src) 
 { 
     dst.reserve(dst.size() + src.holes.size() + 1);

src/libslic3r/Fill/FillBase.cpp

@@ -21,6 +21,8 @@
 #include "FillAdaptive.hpp"
 #include "FillLightning.hpp"
 
+#include <boost/log/trivial.hpp>
+
 // #define INFILL_DEBUG_OUTPUT
 
 namespace Slic3r {
@@ -129,8 +131,8 @@ std::pair<float, Point> Fill::_infill_direction(const Surface *surface) const
     float out_angle = this->angle;
 
 	if (out_angle == FLT_MAX) {
-		//FIXME Vojtech: Add a warning?
+        assert(false);
-        printf("Using undefined infill angle\n");
+        BOOST_LOG_TRIVIAL(error) << "Using undefined infill angle";
         out_angle = 0.f;
     }
 

src/libslic3r/Fill/FillRectilinear.cpp

@@ -414,7 +414,7 @@ public:
 //        bool sticks_removed = 
         remove_sticks(polygons_src);
 //        if (sticks_removed) BOOST_LOG_TRIVIAL(error) << "Sticks removed!";
-        polygons_outer = aoffset1 == 0 ? polygons_src : offset(polygons_src, float(aoffset1), ClipperLib::jtMiter, miterLimit);
+        polygons_outer = aoffset1 == 0 ? to_polygons(polygons_src) : offset(polygons_src, float(aoffset1), ClipperLib::jtMiter, miterLimit);
         if (aoffset2 < 0)
             polygons_inner = shrink(polygons_outer, float(aoffset1 - aoffset2), ClipperLib::jtMiter, miterLimit);
 		// Filter out contours with zero area or small area, contours with 2 points only.

src/libslic3r/GCode.cpp

@@ -3134,14 +3134,25 @@ bool GCode::needs_retraction(const Polyline &travel, ExtrusionRole role)
         return false;
     }
 
-    if (role == erSupportMaterial) {
+    if (role == erSupportMaterial)
-        const SupportLayer* support_layer = dynamic_cast<const SupportLayer*>(m_layer);
+        if (const SupportLayer *support_layer = dynamic_cast<const SupportLayer*>(m_layer);
-        //FIXME support_layer->support_islands.contains should use some search structure!
+            support_layer != nullptr && ! support_layer->support_islands_bboxes.empty()) {
-        if (support_layer != NULL && diff_pl(travel, support_layer->support_islands).empty())
+            BoundingBox bbox_travel = get_extents(travel);
+            Polylines   trimmed;
+            bool        trimmed_initialized = false;
+            for (const BoundingBox &bbox : support_layer->support_islands_bboxes)
+                if (bbox.overlap(bbox_travel)) {
+                    const auto &island = support_layer->support_islands[&bbox - support_layer->support_islands_bboxes.data()];
+                    trimmed = trimmed_initialized ? diff_pl(trimmed, island) : diff_pl(travel, island);
+                    trimmed_initialized = true;
+                    if (trimmed.empty())
                         // skip retraction if this is a travel move inside a support material island
                         //FIXME not retracting over a long path may cause oozing, which in turn may result in missing material
                         // at the end of the extrusion path!
                         return false;
+                    // Not sure whether updating the boudning box isn't too expensive.
+                    //bbox_travel = get_extents(trimmed);
+                }
         }
 
     if (m_config.only_retract_when_crossing_perimeters && m_layer != nullptr &&

src/libslic3r/GCodeWriter.cpp

@@ -23,8 +23,8 @@ void GCodeWriter::apply_print_config(const PrintConfig &print_config)
     bool use_mach_limits = print_config.gcode_flavor.value == gcfMarlinLegacy
                         || print_config.gcode_flavor.value == gcfMarlinFirmware
                         || print_config.gcode_flavor.value == gcfRepRapFirmware;
-    m_max_acceleration = std::lrint((use_mach_limits && print_config.machine_limits_usage.value == MachineLimitsUsage::EmitToGCode) ?
+    m_max_acceleration = static_cast<unsigned int>(std::round((use_mach_limits && print_config.machine_limits_usage.value == MachineLimitsUsage::EmitToGCode) ?
-        print_config.machine_max_acceleration_extruding.values.front() : 0);
+        print_config.machine_max_acceleration_extruding.values.front() : 0));
 }
 
 void GCodeWriter::set_extruders(std::vector<unsigned int> extruder_ids)

src/libslic3r/Layer.hpp

@@ -197,6 +197,8 @@ public:
     // Polygons covered by the supports: base, interface and contact areas.
     // Used to suppress retraction if moving for a support extrusion over these support_islands.
     ExPolygons                  support_islands;
+    // Slightly inflated bounding boxes of the above, for faster intersection query.
+    std::vector<BoundingBox>    support_islands_bboxes;
     // Extrusion paths for the support base and for the support interface and contacts.
     ExtrusionEntityCollection   support_fills;
 

src/libslic3r/PlaceholderParser.cpp

@@ -40,11 +40,11 @@
 #include <boost/lexical_cast.hpp>
 #include <boost/spirit/include/qi.hpp>
 #include <boost/spirit/include/qi_lit.hpp>
-#include <boost/spirit/include/phoenix_core.hpp>
+#include <boost/phoenix/core.hpp>
-#include <boost/spirit/include/phoenix_operator.hpp>
+#include <boost/phoenix/operator.hpp>
-#include <boost/spirit/include/phoenix_fusion.hpp>
+#include <boost/phoenix/fusion.hpp>
-#include <boost/spirit/include/phoenix_stl.hpp>
+#include <boost/phoenix/stl.hpp>
-#include <boost/spirit/include/phoenix_object.hpp>
+#include <boost/phoenix/object.hpp>
 #include <boost/fusion/include/adapt_struct.hpp>
 #include <boost/spirit/repository/include/qi_distinct.hpp>
 #include <boost/spirit/repository/include/qi_iter_pos.hpp>

src/libslic3r/Point.hpp

@@ -142,9 +142,9 @@ public:
     Point() : Vec2crd(0, 0) {}
     Point(int32_t x, int32_t y) : Vec2crd(coord_t(x), coord_t(y)) {}
     Point(int64_t x, int64_t y) : Vec2crd(coord_t(x), coord_t(y)) {}
-    Point(double x, double y) : Vec2crd(coord_t(lrint(x)), coord_t(lrint(y))) {}
+    Point(double x, double y) : Vec2crd(coord_t(std::round(x)), coord_t(std::round(y))) {}
     Point(const Point &rhs) { *this = rhs; }
-	explicit Point(const Vec2d& rhs) : Vec2crd(coord_t(lrint(rhs.x())), coord_t(lrint(rhs.y()))) {}
+	explicit Point(const Vec2d& rhs) : Vec2crd(coord_t(std::round(rhs.x())), coord_t(std::round(rhs.y()))) {}
 	// This constructor allows you to construct Point from Eigen expressions
     template<typename OtherDerived>
     Point(const Eigen::MatrixBase<OtherDerived> &other) : Vec2crd(other) {}
@@ -282,7 +282,7 @@ namespace int128 {
 
 // To be used by std::unordered_map, std::unordered_multimap and friends.
 struct PointHash {
-    size_t operator()(const Vec2crd &pt) const {
+    size_t operator()(const Vec2crd &pt) const noexcept {
         return coord_t((89 * 31 + int64_t(pt.x())) * 31 + pt.y());
     }
 };

src/libslic3r/Polyline.hpp

@@ -61,6 +61,9 @@ public:
         }
     }
   
+    Point& operator[](Points::size_type idx) { return this->points[idx]; }
+    const Point& operator[](Points::size_type idx) const { return this->points[idx]; }
+
     const Point& last_point() const override { return this->points.back(); }
     const Point& leftmost_point() const;
     Lines lines() const override;

src/libslic3r/PrintApply.cpp

@@ -626,7 +626,8 @@ PrintObjectRegions::BoundingBox find_modifier_volume_extents(const PrintObjectRe
             const PrintObjectRegions::VolumeRegion &parent_region  = layer_range.volume_regions[parent_region_id];
             const PrintObjectRegions::BoundingBox  *parent_extents = find_volume_extents(layer_range, *parent_region.model_volume);
             assert(parent_extents);
-            out.extend(*parent_extents);
+            out.clamp(*parent_extents);
+            assert(! out.isEmpty());
             if (parent_region.model_volume->is_model_part())
                 break;
             parent_region_id = parent_region.parent;

src/libslic3r/PrintConfig.cpp

@@ -137,7 +137,8 @@ CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(SupportMaterialPattern)
 
 static const t_config_enum_values s_keys_map_SupportMaterialStyle {
     { "grid",           smsGrid },
-    { "snug",           smsSnug }
+    { "snug",           smsSnug },
+    { "tree",           smsTree }
 };
 CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(SupportMaterialStyle)
 
@@ -2776,8 +2777,10 @@ void PrintConfigDef::init_fff_params()
     def->enum_keys_map = &ConfigOptionEnum<SupportMaterialStyle>::get_enum_values();
     def->enum_values.push_back("grid");
     def->enum_values.push_back("snug");
+    def->enum_values.push_back("tree");
     def->enum_labels.push_back(L("Grid"));
     def->enum_labels.push_back(L("Snug"));
+    def->enum_labels.push_back(L("Tree"));
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionEnum<SupportMaterialStyle>(smsGrid));
 

src/libslic3r/PrintConfig.hpp

@@ -60,7 +60,7 @@ enum InfillPattern : int {
     ipRectilinear, ipMonotonic, ipAlignedRectilinear, ipGrid, ipTriangles, ipStars, ipCubic, ipLine, ipConcentric, ipHoneycomb, ip3DHoneycomb,
     ipGyroid, ipHilbertCurve, ipArchimedeanChords, ipOctagramSpiral, ipAdaptiveCubic, ipSupportCubic, ipSupportBase,
     ipLightning,
-ipCount,
+    ipCount,
 };
 
 enum class IroningType {
@@ -85,7 +85,7 @@ enum SupportMaterialPattern {
 };
 
 enum SupportMaterialStyle {
-    smsGrid, smsSnug,
+    smsGrid, smsSnug, smsTree,
 };
 
 enum SupportMaterialInterfacePattern {

src/libslic3r/PrintObject.cpp

@@ -8,6 +8,7 @@
 #include "Layer.hpp"
 #include "MutablePolygon.hpp"
 #include "SupportMaterial.hpp"
+#include "TreeSupport.hpp"
 #include "Surface.hpp"
 #include "Slicing.hpp"
 #include "Tesselate.hpp"
@@ -1438,56 +1439,64 @@ void PrintObject::discover_vertical_shells()
 //    PROFILE_OUTPUT(debug_out_path("discover_vertical_shells-profile.txt").c_str());
 }
 
-/* This method applies bridge flow to the first internal solid layer above
+// This method applies bridge flow to the first internal solid layer above sparse infill.
-   sparse infill */
 void PrintObject::bridge_over_infill()
 {
     BOOST_LOG_TRIVIAL(info) << "Bridge over infill..." << log_memory_info();
 
-    for (size_t region_id = 0; region_id < this->num_printing_regions(); ++ region_id) {
+    std::vector<int> sparse_infill_regions;
-        const PrintRegion &region = this->printing_region(region_id);
+    for (size_t region_id = 0; region_id < this->num_printing_regions(); ++ region_id)
+        if (const PrintRegion &region = this->printing_region(region_id); region.config().fill_density.value < 100)
+            sparse_infill_regions.emplace_back(region_id);
+    if (this->layer_count() < 2 || sparse_infill_regions.empty())
+        return;
 
-        // skip bridging in case there are no voids
+    // Collect sum of all internal (sparse infill) regions, because
-        if (region.config().fill_density.value == 100)
+    //     1) layerm->fill_surfaces.will be modified in parallel.
-            continue;
+    //     2) the parallel loop works on a sum of surfaces over regions anyways, thus collecting the sparse infill surfaces
+    //        up front is an optimization.
+    std::vector<Polygons> internals;
+    internals.reserve(this->layer_count());
+    for (Layer *layer : m_layers) {
+        Polygons sum;
+        for (const LayerRegion *layerm : layer->m_regions)
+            layerm->fill_surfaces.filter_by_type(stInternal, &sum);
+        internals.emplace_back(std::move(sum));
+    }
 
-		for (LayerPtrs::iterator layer_it = m_layers.begin(); layer_it != m_layers.end(); ++ layer_it) {
+    // Process all regions and layers in parallel.
-            // skip first layer
+    tbb::parallel_for(tbb::blocked_range<size_t>(0, sparse_infill_regions.size() * (this->layer_count() - 1), sparse_infill_regions.size()),
-			if (layer_it == m_layers.begin())
+        [this, &sparse_infill_regions, &internals]
-                continue;
+        (const tbb::blocked_range<size_t> &range) {
-            
+        for (size_t task_id = range.begin(); task_id != range.end(); ++ task_id) {
-            Layer       *layer       = *layer_it;
+            const size_t layer_id    = (task_id / sparse_infill_regions.size()) + 1;
+            const size_t region_id   = sparse_infill_regions[task_id % sparse_infill_regions.size()];
+            Layer       *layer       = this->get_layer(layer_id);
             LayerRegion *layerm      = layer->m_regions[region_id];
             Flow         bridge_flow = layerm->bridging_flow(frSolidInfill);
 
-            // extract the stInternalSolid surfaces that might be transformed into bridges
+            // Extract the stInternalSolid surfaces that might be transformed into bridges.
-            Polygons internal_solid;
+            ExPolygons internal_solid;
-            layerm->fill_surfaces.filter_by_type(stInternalSolid, &internal_solid);
+            layerm->fill_surfaces.remove_type(stInternalSolid, &internal_solid);
+            if (internal_solid.empty())
+                // No internal solid -> no new bridges for this layer region.
+                continue;
 
             // check whether the lower area is deep enough for absorbing the extra flow
             // (for obvious physical reasons but also for preventing the bridge extrudates
             // from overflowing in 3D preview)
             ExPolygons to_bridge;
             {
-                Polygons to_bridge_pp = internal_solid;
+                Polygons to_bridge_pp = to_polygons(internal_solid);
-                
+                // Iterate through lower layers spanned by bridge_flow.
-                // iterate through lower layers spanned by bridge_flow
                 double bottom_z = layer->print_z - bridge_flow.height() - EPSILON;
-                for (int i = int(layer_it - m_layers.begin()) - 1; i >= 0; --i) {
+                for (auto i = int(layer_id) - 1; i >= 0; -- i) {
-                    const Layer* lower_layer = m_layers[i];
+                    // Stop iterating if layer is lower than bottom_z.
-                    
+                    if (m_layers[i]->print_z < bottom_z)
-                    // stop iterating if layer is lower than bottom_z
+                        break;
-                    if (lower_layer->print_z < bottom_z) break;
+                    // Intersect lower sparse infills with the candidate solid surfaces.
-                    
+                    to_bridge_pp = intersection(to_bridge_pp, internals[i]);
-                    // iterate through regions and collect internal surfaces
-                    Polygons lower_internal;
-                    for (LayerRegion *lower_layerm : lower_layer->m_regions)
-                        lower_layerm->fill_surfaces.filter_by_type(stInternal, &lower_internal);
-                    
-                    // intersect such lower internal surfaces with the candidate solid surfaces
-                    to_bridge_pp = intersection(to_bridge_pp, lower_internal);
                 }
-                
                 // there's no point in bridging too thin/short regions
                 //FIXME Vojtech: The offset2 function is not a geometric offset, 
                 // therefore it may create 1) gaps, and 2) sharp corners, which are outside the original contour.
@@ -1497,8 +1506,12 @@ void PrintObject::bridge_over_infill()
                     to_bridge_pp = opening(to_bridge_pp, min_width);
                 }
                 
-                if (to_bridge_pp.empty()) continue;
+                if (to_bridge_pp.empty()) {
-                
+                    // Restore internal_solid surfaces. 
+                    for (ExPolygon &ex : internal_solid)
+                        layerm->fill_surfaces.surfaces.push_back(Surface(stInternalSolid, std::move(ex)));
+                    continue;
+                }
                 // convert into ExPolygons
                 to_bridge = union_ex(to_bridge_pp);
             }
@@ -1511,11 +1524,10 @@ void PrintObject::bridge_over_infill()
             ExPolygons not_to_bridge = diff_ex(internal_solid, to_bridge, ApplySafetyOffset::Yes);
             to_bridge = intersection_ex(to_bridge, internal_solid, ApplySafetyOffset::Yes);
             // build the new collection of fill_surfaces
-            layerm->fill_surfaces.remove_type(stInternalSolid);
             for (ExPolygon &ex : to_bridge)
-                layerm->fill_surfaces.surfaces.push_back(Surface(stInternalBridge, ex));
+                layerm->fill_surfaces.surfaces.push_back(Surface(stInternalBridge, std::move(ex)));
             for (ExPolygon &ex : not_to_bridge)
-                layerm->fill_surfaces.surfaces.push_back(Surface(stInternalSolid, ex));            
+                layerm->fill_surfaces.surfaces.push_back(Surface(stInternalSolid, std::move(ex)));
             /*
             # exclude infill from the layers below if needed
             # see discussion at https://github.com/alexrj/Slic3r/issues/240
@@ -1549,14 +1561,13 @@ void PrintObject::bridge_over_infill()
                 }
             }
             */
-
 #ifdef SLIC3R_DEBUG_SLICE_PROCESSING
             layerm->export_region_slices_to_svg_debug("7_bridge_over_infill");
             layerm->export_region_fill_surfaces_to_svg_debug("7_bridge_over_infill");
 #endif /* SLIC3R_DEBUG_SLICE_PROCESSING */
             m_print->throw_if_canceled();
         }
-    }
+    });
 }
 
 static void clamp_exturder_to_default(ConfigOptionInt &opt, size_t num_extruders)
@@ -2125,8 +2136,13 @@ void PrintObject::combine_infill()
 
 void PrintObject::_generate_support_material()
 {
+    if (m_config.support_material_style == smsTree) {
+        TreeSupport tree_support;
+        tree_support.generateSupportAreas(*this);
+    } else {
         PrintObjectSupportMaterial support_material(this, m_slicing_params);
         support_material.generate(*this);
+    }
 }
 
 static void project_triangles_to_slabs(ConstLayerPtrsAdaptor layers, const indexed_triangle_set &custom_facets, const Transform3f &tr, bool seam, std::vector<Polygons> &out)

src/libslic3r/SLA/Pad.cpp

@@ -204,7 +204,7 @@ public:
     void add(const ExPolygon &ep)
     {
         m_polys.emplace_back(ep);
-        m_index.insert(BoundingBox{ep}, unsigned(m_index.size()));
+        m_index.insert(get_extents(ep), unsigned(m_index.size()));
     }
 
     // Check an arbitrary polygon for intersection with the indexed polygons

src/libslic3r/SVG.cpp

@@ -88,10 +88,8 @@ void SVG::draw(const ExPolygon &expolygon, std::string fill, const float fill_op
     this->fill = fill;
     
     std::string d;
-    Polygons pp = expolygon;
+    for (const Polygon &p : to_polygons(expolygon))
-    for (Polygons::const_iterator p = pp.begin(); p != pp.end(); ++p) {
+        d += this->get_path_d(p, true) + " ";
-        d += this->get_path_d(*p, true) + " ";
-    }
     this->path(d, true, 0, fill_opacity);
 }
 
@@ -359,7 +357,7 @@ void SVG::export_expolygons(const char *path, const std::vector<std::pair<Slic3r
     for (const auto &exp_with_attr : expolygons_with_attributes)
     	if (exp_with_attr.second.radius_points > 0)
 			for (const ExPolygon &expoly : exp_with_attr.first)
-    			svg.draw((Points)expoly, exp_with_attr.second.color_points, exp_with_attr.second.radius_points);
+    			svg.draw(to_points(expoly), exp_with_attr.second.color_points, exp_with_attr.second.radius_points);
 
     // Export legend.
     // 1st row

src/libslic3r/SupportMaterial.hpp

@@ -11,53 +11,46 @@ class PrintObject;
 class PrintConfig;
 class PrintObjectConfig;
 
-// This class manages raft and supports for a single PrintObject.
+// Support layer type to be used by SupportGeneratorLayer. This type carries a much more detailed information
-// Instantiated by Slic3r::Print::Object->_support_material()
+// about the support layer type than the final support layers stored in a PrintObject.
-// This class is instantiated before the slicing starts as Object.pm will query
+enum SupporLayerType {
-// the parameters of the raft to determine the 1st layer height and thickness.
+	Unknown = 0,
-class PrintObjectSupportMaterial
+	// Ratft base layer, to be printed with the support material.
+	RaftBase,
+	// Raft interface layer, to be printed with the support interface material. 
+	RaftInterface,
+	// Bottom contact layer placed over a top surface of an object. To be printed with a support interface material.
+	BottomContact,
+	// Dense interface layer, to be printed with the support interface material.
+	// This layer is separated from an object by an BottomContact layer.
+	BottomInterface,
+	// Sparse base support layer, to be printed with a support material.
+	Base,
+	// Dense interface layer, to be printed with the support interface material.
+	// This layer is separated from an object with TopContact layer.
+	TopInterface,
+	// Top contact layer directly supporting an overhang. To be printed with a support interface material.
+	TopContact,
+	// Some undecided type yet. It will turn into Base first, then it may turn into BottomInterface or TopInterface.
+	Intermediate,
+};
+
+// A support layer type used internally by the SupportMaterial class. This class carries a much more detailed
+// information about the support layer than the layers stored in the PrintObject, mainly
+// the SupportGeneratorLayer is aware of the bridging flow and the interface gaps between the object and the support.
+class SupportGeneratorLayer
 {
 public:
-	// Support layer type to be used by MyLayer. This type carries a much more detailed information
-	// about the support layer type than the final support layers stored in a PrintObject.
-	enum SupporLayerType {
-		sltUnknown = 0,
-		// Ratft base layer, to be printed with the support material.
-		sltRaftBase,
-		// Raft interface layer, to be printed with the support interface material. 
-		sltRaftInterface,
-		// Bottom contact layer placed over a top surface of an object. To be printed with a support interface material.
-		sltBottomContact,
-		// Dense interface layer, to be printed with the support interface material.
-		// This layer is separated from an object by an sltBottomContact layer.
-		sltBottomInterface,
-		// Sparse base support layer, to be printed with a support material.
-		sltBase,
-		// Dense interface layer, to be printed with the support interface material.
-		// This layer is separated from an object with sltTopContact layer.
-		sltTopInterface,
-		// Top contact layer directly supporting an overhang. To be printed with a support interface material.
-		sltTopContact,
-		// Some undecided type yet. It will turn into sltBase first, then it may turn into sltBottomInterface or sltTopInterface.
-		sltIntermediate,
-	};
-
-	// A support layer type used internally by the SupportMaterial class. This class carries a much more detailed
-	// information about the support layer than the layers stored in the PrintObject, mainly
-	// the MyLayer is aware of the bridging flow and the interface gaps between the object and the support.
-	class MyLayer
-	{
-	public:
 	void reset() {
-			*this = MyLayer();
+		*this = SupportGeneratorLayer();
 	}
 
-		bool operator==(const MyLayer &layer2) const {
+	bool operator==(const SupportGeneratorLayer &layer2) const {
 		return print_z == layer2.print_z && height == layer2.height && bridging == layer2.bridging;
 	}
 
 	// Order the layers by lexicographically by an increasing print_z and a decreasing layer height.
-		bool operator<(const MyLayer &layer2) const {
+	bool operator<(const SupportGeneratorLayer &layer2) const {
 		if (print_z < layer2.print_z) {
 			return true;
 		} else if (print_z == layer2.print_z) {
@@ -72,7 +65,7 @@ public:
 			return false;
 	}
 
-		void merge(MyLayer &&rhs) {
+	void merge(SupportGeneratorLayer &&rhs) {
         // The union_() does not support move semantic yet, but maybe one day it will.
         this->polygons = union_(this->polygons, std::move(rhs.polygons));
         auto merge = [](std::unique_ptr<Polygons> &dst, std::unique_ptr<Polygons> &src) {
@@ -92,9 +85,9 @@ public:
 	coordf_t bottom_print_z() const { return print_z - height; }
 
 	// To sort the extremes of top / bottom interface layers.
-		coordf_t extreme_z() const { return (this->layer_type == sltTopContact) ? this->bottom_z : this->print_z; }
+	coordf_t extreme_z() const { return (this->layer_type == SupporLayerType::TopContact) ? this->bottom_z : this->print_z; }
 
-		SupporLayerType layer_type { sltUnknown };
+	SupporLayerType layer_type { SupporLayerType::Unknown };
 	// Z used for printing, in unscaled coordinates.
 	coordf_t print_z { 0 };
 	// Bottom Z of this layer. For soluble layers, bottom_z + height = print_z,
@@ -118,9 +111,17 @@ public:
 	std::unique_ptr<Polygons> overhang_polygons;
 	// Enforcers need to be propagated independently in case the "support on build plate only" option is enabled.
 	std::unique_ptr<Polygons> enforcer_polygons;
-	};
+};
+
+// Layers are allocated and owned by a deque. Once a layer is allocated, it is maintained
+// up to the end of a generate() method. The layer storage may be replaced by an allocator class in the future, 
+// which would allocate layers by multiple chunks.
+using SupportGeneratorLayerStorage	= std::deque<SupportGeneratorLayer>;
+using SupportGeneratorLayersPtr		= std::vector<SupportGeneratorLayer*>;
+
+struct SupportParameters {
+	SupportParameters(const PrintObject &object);
 
-	struct SupportParams {
 	Flow 					first_layer_flow;
 	Flow 					support_material_flow;
 	Flow 					support_material_interface_flow;
@@ -129,7 +130,7 @@ public:
 	bool 					can_merge_support_regions;
 
     coordf_t 				support_layer_height_min;
-	//	coordf_t	support_layer_height_max;
+//	coordf_t				support_layer_height_max;
 
 	coordf_t				gap_xy;
 
@@ -144,14 +145,53 @@ public:
     InfillPattern           interface_fill_pattern;
     InfillPattern 			contact_fill_pattern;
     bool                    with_sheath;
-	};
+};
 
-	// Layers are allocated and owned by a deque. Once a layer is allocated, it is maintained
+// Generate raft layers, also expand the 1st support layer
-	// up to the end of a generate() method. The layer storage may be replaced by an allocator class in the future, 
+// in case there is no raft layer to improve support adhesion.
-	// which would allocate layers by multiple chunks.
+SupportGeneratorLayersPtr generate_raft_base(
-	typedef std::deque<MyLayer> 				MyLayerStorage;
+	const PrintObject				&object,
-	typedef std::vector<MyLayer*> 				MyLayersPtr;
+	const SupportParameters			&support_params,
+	const SlicingParameters			&slicing_params,
+	const SupportGeneratorLayersPtr &top_contacts,
+	const SupportGeneratorLayersPtr &interface_layers,
+	const SupportGeneratorLayersPtr &base_interface_layers,
+	const SupportGeneratorLayersPtr &base_layers,
+	SupportGeneratorLayerStorage    &layer_storage);
 
+// returns sorted layers
+SupportGeneratorLayersPtr generate_support_layers(
+	PrintObject							&object,
+    const SupportGeneratorLayersPtr     &raft_layers,
+    const SupportGeneratorLayersPtr     &bottom_contacts,
+    const SupportGeneratorLayersPtr     &top_contacts,
+    const SupportGeneratorLayersPtr     &intermediate_layers,
+    const SupportGeneratorLayersPtr     &interface_layers,
+    const SupportGeneratorLayersPtr     &base_interface_layers);
+
+// Produce the support G-code.
+// Used by both classic and tree supports.
+void generate_support_toolpaths(
+	SupportLayerPtrs    				&support_layers,
+	const PrintObjectConfig 			&config,
+	const SupportParameters 			&support_params,
+	const SlicingParameters 			&slicing_params,
+    const SupportGeneratorLayersPtr 	&raft_layers,
+    const SupportGeneratorLayersPtr   	&bottom_contacts,
+    const SupportGeneratorLayersPtr   	&top_contacts,
+    const SupportGeneratorLayersPtr   	&intermediate_layers,
+	const SupportGeneratorLayersPtr   	&interface_layers,
+    const SupportGeneratorLayersPtr   	&base_interface_layers);
+
+void export_print_z_polygons_to_svg(const char *path, SupportGeneratorLayer ** const layers, size_t n_layers);
+void export_print_z_polygons_and_extrusions_to_svg(const char *path, SupportGeneratorLayer ** const layers, size_t n_layers, SupportLayer& support_layer);
+
+// This class manages raft and supports for a single PrintObject.
+// Instantiated by Slic3r::Print::Object->_support_material()
+// This class is instantiated before the slicing starts as Object.pm will query
+// the parameters of the raft to determine the 1st layer height and thickness.
+class PrintObjectSupportMaterial
+{
 public:
 	PrintObjectSupportMaterial(const PrintObject *object, const SlicingParameters &slicing_params);
 
@@ -175,58 +215,48 @@ private:
 	// Generate top contact layers supporting overhangs.
 	// For a soluble interface material synchronize the layer heights with the object, otherwise leave the layer height undefined.
 	// If supports over bed surface only are requested, don't generate contact layers over an object.
-	MyLayersPtr top_contact_layers(const PrintObject &object, const std::vector<Polygons> &buildplate_covered, MyLayerStorage &layer_storage) const;
+	SupportGeneratorLayersPtr top_contact_layers(const PrintObject &object, const std::vector<Polygons> &buildplate_covered, SupportGeneratorLayerStorage &layer_storage) const;
 
 	// Generate bottom contact layers supporting the top contact layers.
 	// For a soluble interface material synchronize the layer heights with the object, 
 	// otherwise set the layer height to a bridging flow of a support interface nozzle.
-	MyLayersPtr bottom_contact_layers_and_layer_support_areas(
+	SupportGeneratorLayersPtr bottom_contact_layers_and_layer_support_areas(
-		const PrintObject &object, const MyLayersPtr &top_contacts, std::vector<Polygons> &buildplate_covered, 
+		const PrintObject &object, const SupportGeneratorLayersPtr &top_contacts, std::vector<Polygons> &buildplate_covered, 
-		MyLayerStorage &layer_storage, std::vector<Polygons> &layer_support_areas) const;
+		SupportGeneratorLayerStorage &layer_storage, std::vector<Polygons> &layer_support_areas) const;
 
 	// Trim the top_contacts layers with the bottom_contacts layers if they overlap, so there would not be enough vertical space for both of them.
-	void trim_top_contacts_by_bottom_contacts(const PrintObject &object, const MyLayersPtr &bottom_contacts, MyLayersPtr &top_contacts) const;
+	void trim_top_contacts_by_bottom_contacts(const PrintObject &object, const SupportGeneratorLayersPtr &bottom_contacts, SupportGeneratorLayersPtr &top_contacts) const;
 
 	// Generate raft layers and the intermediate support layers between the bottom contact and top contact surfaces.
-	MyLayersPtr raft_and_intermediate_support_layers(
+	SupportGeneratorLayersPtr raft_and_intermediate_support_layers(
 	    const PrintObject   &object,
-	    const MyLayersPtr   &bottom_contacts,
+	    const SupportGeneratorLayersPtr   &bottom_contacts,
-	    const MyLayersPtr   &top_contacts,
+	    const SupportGeneratorLayersPtr   &top_contacts,
-	    MyLayerStorage	 	&layer_storage) const;
+	    SupportGeneratorLayerStorage	 	&layer_storage) const;
 
 	// Fill in the base layers with polygons.
 	void generate_base_layers(
 	    const PrintObject   &object,
-	    const MyLayersPtr   &bottom_contacts,
+	    const SupportGeneratorLayersPtr   &bottom_contacts,
-	    const MyLayersPtr   &top_contacts,
+	    const SupportGeneratorLayersPtr   &top_contacts,
-	    MyLayersPtr         &intermediate_layers,
+	    SupportGeneratorLayersPtr         &intermediate_layers,
 	    const std::vector<Polygons> &layer_support_areas) const;
 
-	// Generate raft layers, also expand the 1st support layer
-	// in case there is no raft layer to improve support adhesion.
-    MyLayersPtr generate_raft_base(
-    	const PrintObject   &object,
-	    const MyLayersPtr   &top_contacts,
-	    const MyLayersPtr   &interface_layers,
-	    const MyLayersPtr   &base_interface_layers,
-	    const MyLayersPtr   &base_layers,
-	    MyLayerStorage      &layer_storage) const;
-
 	// Turn some of the base layers into base interface layers.
 	// For soluble interfaces with non-soluble bases, print maximum two first interface layers with the base
 	// extruder to improve adhesion of the soluble filament to the base.
-	std::pair<MyLayersPtr, MyLayersPtr> generate_interface_layers(
+	std::pair<SupportGeneratorLayersPtr, SupportGeneratorLayersPtr> generate_interface_layers(
-	    const MyLayersPtr   &bottom_contacts,
+	    const SupportGeneratorLayersPtr   &bottom_contacts,
-	    const MyLayersPtr   &top_contacts,
+	    const SupportGeneratorLayersPtr   &top_contacts,
-	    MyLayersPtr         &intermediate_layers,
+	    SupportGeneratorLayersPtr         &intermediate_layers,
-	    MyLayerStorage      &layer_storage) const;
+	    SupportGeneratorLayerStorage      &layer_storage) const;
 	
 
 	// Trim support layers by an object to leave a defined gap between
 	// the support volume and the object.
 	void trim_support_layers_by_object(
 	    const PrintObject   &object,
-	    MyLayersPtr         &support_layers,
+	    SupportGeneratorLayersPtr         &support_layers,
 	    const coordf_t       gap_extra_above,
 	    const coordf_t       gap_extra_below,
 	    const coordf_t       gap_xy) const;
@@ -236,16 +266,6 @@ private:
 	void clip_with_shape();
 */
 
-	// Produce the actual G-code.
-	void generate_toolpaths(
-		SupportLayerPtrs    &support_layers,
-        const MyLayersPtr 	&raft_layers,
-        const MyLayersPtr   &bottom_contacts,
-        const MyLayersPtr   &top_contacts,
-        const MyLayersPtr   &intermediate_layers,
-		const MyLayersPtr   &interface_layers,
-        const MyLayersPtr   &base_interface_layers) const;
-
 	// Following objects are not owned by SupportMaterial class.
 	const PrintObject 		*m_object;
 	const PrintConfig 		*m_print_config;
@@ -254,7 +274,7 @@ private:
 	// carrying information on a raft, 1st layer height, 1st object layer height, gap between the raft and object etc.
 	SlicingParameters	     m_slicing_params;
 	// Various precomputed support parameters to be shared with external functions.
-	SupportParams 			 m_support_params;
+	SupportParameters 		 m_support_params;
 };
 
 } // namespace Slic3r

src/libslic3r/SurfaceCollection.cpp

@@ -65,14 +65,11 @@ SurfacesPtr SurfaceCollection::filter_by_types(const SurfaceType *types, int nty
     return ss;
 }
 
-void SurfaceCollection::filter_by_type(SurfaceType type, Polygons* polygons)
+void SurfaceCollection::filter_by_type(SurfaceType type, Polygons *polygons) const
 {
-    for (Surfaces::iterator surface = this->surfaces.begin(); surface != this->surfaces.end(); ++surface) {
+    for (const Surface &surface : this->surfaces)
-        if (surface->surface_type == type) {
+        if (surface.surface_type == type)
-            Polygons pp = surface->expolygon;
+            polygons_append(*polygons, to_polygons(surface.expolygon));
-            polygons->insert(polygons->end(), pp.begin(), pp.end());
-        }
-    }
 }
 
 void SurfaceCollection::keep_type(const SurfaceType type)
@@ -124,6 +121,22 @@ void SurfaceCollection::remove_type(const SurfaceType type)
         surfaces.erase(surfaces.begin() + j, surfaces.end());
 }
 
+void SurfaceCollection::remove_type(const SurfaceType type, ExPolygons *polygons)
+{
+    size_t j = 0;
+    for (size_t i = 0; i < surfaces.size(); ++ i) {
+        if (Surface &surface = surfaces[i]; surface.surface_type == type) {
+            polygons->emplace_back(std::move(surface.expolygon));
+        } else {
+            if (j < i)
+                std::swap(surfaces[i], surfaces[j]);
+            ++ j;
+        }
+    }
+    if (j < surfaces.size())
+        surfaces.erase(surfaces.begin() + j, surfaces.end());
+}
+
 void SurfaceCollection::remove_types(const SurfaceType *types, int ntypes)
 {
     size_t j = 0;

src/libslic3r/SurfaceCollection.hpp

@@ -32,7 +32,8 @@ public:
     void keep_types(const SurfaceType *types, int ntypes);
     void remove_type(const SurfaceType type);
     void remove_types(const SurfaceType *types, int ntypes);
-    void filter_by_type(SurfaceType type, Polygons* polygons);
+    void filter_by_type(SurfaceType type, Polygons *polygons) const;
+    void remove_type(const SurfaceType type, ExPolygons *polygons);
     void set_type(SurfaceType type) {
     	for (Surface &surface : this->surfaces)
     		surface.surface_type = type;

src/libslic3r/TreeModelVolumes.cpp

@@ -0,0 +1,762 @@
+// Tree supports by Thomas Rahm, losely based on Tree Supports by CuraEngine.
+// Original source of Thomas Rahm's tree supports:
+// https://github.com/ThomasRahm/CuraEngine
+//
+// Original CuraEngine copyright:
+// Copyright (c) 2021 Ultimaker B.V.
+// CuraEngine is released under the terms of the AGPLv3 or higher.
+
+#include "TreeModelVolumes.hpp"
+#include "TreeSupport.hpp"
+
+#include "BuildVolume.hpp"
+#include "ClipperUtils.hpp"
+#include "Flow.hpp"
+#include "Layer.hpp"
+#include "Point.hpp"
+#include "Print.hpp"
+#include "PrintConfig.hpp"
+#include "Utils.hpp"
+
+#include <boost/log/trivial.hpp>
+
+#include <tbb/parallel_for.h>
+#include <tbb/task_group.h>
+
+namespace Slic3r
+{
+
+// or warning
+// had to use a define beacuse the macro processing inside macro BOOST_LOG_TRIVIAL()
+#define error_level_not_in_cache error
+
+TreeSupportMeshGroupSettings::TreeSupportMeshGroupSettings(const PrintObject &print_object)
+{
+    const PrintConfig       &print_config       = print_object.print()->config();
+    const PrintObjectConfig &config             = print_object.config();
+    const SlicingParameters &slicing_params     = print_object.slicing_parameters();
+//    const std::vector<unsigned int>  printing_extruders = print_object.object_extruders();
+
+    // Support must be enabled and set to Tree style.
+    assert(config.support_material);
+    assert(config.support_material_style == smsTree);
+
+    // Calculate maximum external perimeter width over all printing regions, taking into account the default layer height.
+    coordf_t external_perimeter_width = 0.;
+    for (size_t region_id = 0; region_id < print_object.num_printing_regions(); ++ region_id) {
+        const PrintRegion &region = print_object.printing_region(region_id);
+        external_perimeter_width = std::max<coordf_t>(external_perimeter_width, region.flow(print_object, frExternalPerimeter, config.layer_height).width());
+    }
+
+    this->layer_height              = scaled<coord_t>(config.layer_height.value);
+    this->resolution                = scaled<coord_t>(print_config.gcode_resolution.value);
+    this->min_feature_size          = scaled<coord_t>(config.min_feature_size.value);
+    this->support_angle             = M_PI / 2. - config.support_material_angle * M_PI / 180.;
+    this->support_line_width        = support_material_flow(&print_object, config.layer_height).scaled_width();
+    this->support_roof_line_width   = support_material_interface_flow(&print_object, config.layer_height).scaled_width();
+    //FIXME add it to SlicingParameters and reuse in both tree and normal supports?
+    this->support_bottom_enable     = config.support_material_interface_layers.value > 0 && config.support_material_bottom_interface_layers.value != 0;
+    this->support_bottom_height     = this->support_bottom_enable ?
+        (config.support_material_bottom_interface_layers.value > 0 ?
+            config.support_material_bottom_interface_layers.value :
+            config.support_material_interface_layers.value) * this->layer_height :
+        0;
+    this->support_material_buildplate_only = config.support_material_buildplate_only;
+//    this->support_xy_overrides_z    = 
+    this->support_xy_distance       = scaled<coord_t>(config.support_material_xy_spacing.get_abs_value(external_perimeter_width));
+    // Separation of interfaces, it is likely smaller than support_xy_distance.
+    this->support_xy_distance_overhang = std::min(this->support_xy_distance, scaled<coord_t>(0.5 * external_perimeter_width));
+    this->support_top_distance      = scaled<coord_t>(slicing_params.gap_support_object);
+    this->support_bottom_distance   = scaled<coord_t>(slicing_params.gap_object_support);
+//    this->support_interface_skip_height =
+//    this->support_infill_angles     = 
+    this->support_roof_enable       = config.support_material_interface_layers.value > 0;
+    this->support_roof_height       = config.support_material_interface_layers.value * this->layer_height;
+//    this->minimum_roof_area         = 
+//    this->support_roof_angles       = 
+    this->support_roof_pattern      = config.support_material_interface_pattern;
+    this->support_pattern           = config.support_material_pattern;
+    this->support_line_spacing      = scaled<coord_t>(config.support_material_spacing.value);
+//    this->support_bottom_offset     = 
+    this->support_wall_count        = config.support_material_with_sheath ? 1 : 0;
+    this->support_roof_line_distance = scaled<coord_t>(config.support_material_interface_spacing.value) + this->support_roof_line_width;
+//    this->minimum_support_area      = 
+//    this->minimum_bottom_area       = 
+//    this->support_offset            = 
+}
+
+//FIXME Machine border is currently ignored.
+static Polygons calculateMachineBorderCollision(Polygon machine_border)
+{
+    // Put a border of 1m around the print volume so that we don't collide.
+#if 1
+    //FIXME just returning no border will let tree support legs collide with print bed boundary
+    return {};
+#else
+    //FIXME offsetting by 1000mm easily overflows int32_tr coordinate.
+    Polygons out = offset(machine_border, scaled<float>(1000.), jtMiter, 1.2);
+    machine_border.reverse(); // Makes the polygon negative so that we subtract the actual volume from the collision area.
+    out.emplace_back(std::move(machine_border));
+    return out;
+#endif
+}
+
+TreeModelVolumes::TreeModelVolumes(
+    const PrintObject &print_object,
+    const BuildVolume &build_volume,
+    const coord_t max_move, const coord_t max_move_slow, size_t current_mesh_idx, 
+    double progress_multiplier, double progress_offset, const std::vector<Polygons>& additional_excluded_areas) :
+    // -2 to avoid rounding errors
+    m_max_move{ std::max<coord_t>(max_move - 2, 0) }, m_max_move_slow{ std::max<coord_t>(max_move_slow - 2, 0) }, 
+    m_progress_multiplier{ progress_multiplier }, m_progress_offset{ progress_offset }, 
+    m_machine_border{ calculateMachineBorderCollision(build_volume.polygon()) }
+{
+#if 0
+    std::unordered_map<size_t, size_t> mesh_to_layeroutline_idx;
+    for (size_t mesh_idx = 0; mesh_idx < storage.meshes.size(); ++ mesh_idx) {
+        SliceMeshStorage mesh = storage.meshes[mesh_idx];
+        bool added = false;
+        for (size_t idx = 0; idx < m_layer_outlines.size(); ++ idx)
+            if (TreeSupport::TreeSupportSettings(m_layer_outlines[idx].first) == TreeSupport::TreeSupportSettings(mesh.settings)) {
+                added = true;
+                mesh_to_layeroutline_idx[mesh_idx] = idx;
+            }
+        if (! added) {
+            mesh_to_layeroutline_idx[mesh_idx] = m_layer_outlines.size();
+            m_layer_outlines.emplace_back(mesh.settings, std::vector<Polygons>(storage.support.supportLayers.size(), Polygons()));
+        }
+    }
+    for (size_t idx = 0; idx < m_layer_outlines.size(); ++ idx) {
+        tbb::parallel_for(tbb::blocked_range<size_t>(0, m_layer_outlines[idx].second.size()),
+            [&](const tbb::blocked_range<size_t> &range) {
+            for (const size_t layer_idx = range.begin(); layer_idx < range.end(); ++ layer_idx)
+                m_layer_outlines[idx].second[layer_idx] = union_(m_layer_outlines[idx].second[layer_idx]); 
+        });
+    }
+    m_current_outline_idx = mesh_to_layeroutline_idx[current_mesh_idx];
+
+#else
+    {
+        m_anti_overhang = print_object.slice_support_blockers();
+        TreeSupportMeshGroupSettings mesh_settings(print_object);
+        m_layer_outlines.emplace_back(mesh_settings, std::vector<Polygons>{});
+        m_current_outline_idx = 0;
+        std::vector<Polygons> &outlines = m_layer_outlines.front().second;
+        outlines.assign(print_object.layer_count(), Polygons{});
+        tbb::parallel_for(tbb::blocked_range<size_t>(0, print_object.layer_count(), std::min<size_t>(1, std::max<size_t>(16, print_object.layer_count() / (8 * tbb::this_task_arena::max_concurrency())))),
+            [&](const tbb::blocked_range<size_t> &range) {
+            for (size_t layer_idx = range.begin(); layer_idx < range.end(); ++ layer_idx)
+                outlines[layer_idx] = to_polygons(expolygons_simplify(print_object.get_layer(layer_idx)->lslices, mesh_settings.resolution));
+        });
+    }
+#endif
+
+    m_support_rests_on_model = false;
+    m_min_resolution  = std::numeric_limits<coord_t>::max();
+    for (auto data_pair : m_layer_outlines) {
+        m_support_rests_on_model |= ! data_pair.first.support_material_buildplate_only;
+        m_min_resolution = std::min(m_min_resolution, data_pair.first.resolution);
+    }
+
+    const TreeSupport::TreeSupportSettings config{ m_layer_outlines[m_current_outline_idx].first };
+    if (! config.support_xy_overrides_z) {
+        m_current_min_xy_dist = config.xy_min_distance;
+        if (TreeSupport::TreeSupportSettings::has_to_rely_on_min_xy_dist_only)
+            m_current_min_xy_dist = std::max(m_current_min_xy_dist, coord_t(100));
+        m_current_min_xy_dist_delta = std::max(config.xy_distance - m_current_min_xy_dist, coord_t(0));
+    } else {
+        m_current_min_xy_dist = config.xy_distance;
+        m_current_min_xy_dist_delta = 0;
+    }
+    m_increase_until_radius = config.increase_radius_until_radius;
+    m_radius_0 = config.getRadius(0);
+
+#if 0
+    for (size_t mesh_idx = 0; mesh_idx < storage.meshes.size(); mesh_idx++) {
+        SliceMeshStorage mesh = storage.meshes[mesh_idx];
+        tbb::parallel_for(tbb::blocked_range<size_t>(0, m_layer_outlines[mesh_to_layeroutline_idx[mesh_idx]].second.size()),
+            [&](const tbb::blocked_range<size_t> &range) {
+            for (size_t layer_idx = range.begin(); layer_idx < range.end(); ++ layer_idx)
+                if (layer_idx < mesh.layer_nr_max_filled_layer) {
+                    Polygons outline = extractOutlineFromMesh(mesh, layer_idx);
+                    append(m_layer_outlines[mesh_to_layeroutline_idx[mesh_idx]].second[layer_idx], outline);
+                }
+        });
+    }
+    if (! additional_excluded_areas.empty()) {
+        tbb::parallel_for(tbb::blocked_range<size_t>(0, m_anti_overhang.size()),
+            [&](const tbb::blocked_range<size_t> &range) {
+            for (size_t layer_idx = range.begin(); layer_idx < range.end(); ++ layer_idx) {
+                if (layer_idx < coord_t(additional_excluded_areas.size()))
+                    append(m_anti_overhang[layer_idx], additional_excluded_areas[layer_idx]);
+    //          if (SUPPORT_TREE_AVOID_SUPPORT_BLOCKER)
+    //              append(m_anti_overhang[layer_idx], storage.support.supportLayers[layer_idx].anti_overhang);
+    //FIXME block wipe tower
+    //          if (storage.primeTower.enabled)
+    //              append(m_anti_overhang[layer_idx], layer_idx == 0 ? storage.primeTower.outer_poly_first_layer : storage.primeTower.outer_poly);
+                m_anti_overhang[layer_idx] = union_(m_anti_overhang[layer_idx]);
+            }
+        });
+    }
+#endif
+}
+
+void TreeModelVolumes::precalculate(const coord_t max_layer)
+{
+    auto t_start = std::chrono::high_resolution_clock::now();
+    m_precalculated = true;
+
+    // Get the config corresponding to one mesh that is in the current group. Which one has to be irrelevant.
+    // Not the prettiest way to do this, but it ensures some calculations that may be a bit more complex
+    // like inital layer diameter are only done in once.
+    TreeSupport::TreeSupportSettings config(m_layer_outlines[m_current_outline_idx].first);
+
+    {
+        // calculate which radius each layer in the tip may have.
+        std::vector<coord_t> possible_tip_radiis;
+        for (size_t distance_to_top = 0; distance_to_top <= config.tip_layers; ++ distance_to_top) {
+            possible_tip_radiis.emplace_back(ceilRadius(config.getRadius(distance_to_top)));
+            possible_tip_radiis.emplace_back(ceilRadius(config.getRadius(distance_to_top) + m_current_min_xy_dist_delta));
+        }
+        sort_remove_duplicates(possible_tip_radiis);
+        // It theoretically may happen in the tip, that the radius can change so much in-between 2 layers, 
+        // that a ceil step is skipped (as in there is a radius r so that ceilRadius(radius(dtt))<ceilRadius(r)<ceilRadius(radius(dtt+1))). 
+        // As such a radius will not reasonable happen in the tree and it will most likely not be requested,
+        // there is no need to calculate them. So just skip these.
+        for (coord_t radius_eval = m_radius_0; radius_eval <= config.branch_radius; radius_eval = ceilRadius(radius_eval + 1))
+            if (! std::binary_search(possible_tip_radiis.begin(), possible_tip_radiis.end(), radius_eval))
+                m_ignorable_radii.emplace_back(radius_eval);
+    }
+
+    // it may seem that the required avoidance can be of a smaller radius when going to model (no initial layer diameter for to model branches)
+    // but as for every branch going towards the bp, the to model avoidance is required to check for possible merges with to model branches, this assumption is in-fact wrong.
+    std::unordered_map<coord_t, LayerIndex> radius_until_layer;
+    // while it is possible to calculate, up to which layer the avoidance should be calculated, this simulation is easier to understand, and does not need to be adjusted if something of the radius calculation is changed.
+    // Overhead with an assumed worst case of 6600 layers was about 2ms
+    for (LayerIndex distance_to_top = 0; distance_to_top <= max_layer; ++ distance_to_top) {
+        const LayerIndex current_layer = max_layer - distance_to_top;
+        auto update_radius_until_layer = [&radius_until_layer, current_layer](coord_t r) {
+            auto it = radius_until_layer.find(r);
+            if (it == radius_until_layer.end())
+                radius_until_layer.emplace_hint(it, r, current_layer);
+        };
+        // regular radius
+        update_radius_until_layer(ceilRadius(config.getRadius(distance_to_top, 0) + m_current_min_xy_dist_delta));
+        // the maximum radius that the radius with the min_xy_dist can achieve
+        update_radius_until_layer(ceilRadius(config.getRadius(distance_to_top, 0)));
+        update_radius_until_layer(ceilRadius(config.recommendedMinRadius(current_layer) + m_current_min_xy_dist_delta));
+    }
+
+    // Copy to deque to use in parallel for later.
+    std::vector<RadiusLayerPair> relevant_avoidance_radiis{ radius_until_layer.begin(), radius_until_layer.end() };
+
+    // Append additional radiis needed for collision.
+    // To calculate collision holefree for every radius, the collision of radius m_increase_until_radius will be required.
+    radius_until_layer[ceilRadius(m_increase_until_radius + m_current_min_xy_dist_delta)] = max_layer;
+    // Collision for radius 0 needs to be calculated everywhere, as it will be used to ensure valid xy_distance in drawAreas.
+    radius_until_layer[0] = max_layer;
+    if (m_current_min_xy_dist_delta != 0)
+        radius_until_layer[m_current_min_xy_dist_delta] = max_layer;
+
+    // Now that required_avoidance_limit contains the maximum of ild and regular required radius just copy.
+    std::vector<RadiusLayerPair> relevant_collision_radiis{ radius_until_layer.begin(), radius_until_layer.end() };
+
+    // Calculate the relevant collisions
+    calculateCollision(relevant_collision_radiis);
+
+    // calculate a separate Collisions with all holes removed. These are relevant for some avoidances that try to avoid holes (called safe)
+    std::vector<RadiusLayerPair> relevant_hole_collision_radiis;
+    for (RadiusLayerPair key : relevant_avoidance_radiis)
+        if (key.first < m_increase_until_radius + m_current_min_xy_dist_delta)
+            relevant_hole_collision_radiis.emplace_back(key);
+
+    // Calculate collisions without holes, built from regular collision
+    calculateCollisionHolefree(relevant_hole_collision_radiis);
+    // Let placables be calculated from calculateAvoidance() for better parallelization.
+    if (m_support_rests_on_model)
+        calculatePlaceables(relevant_avoidance_radiis);
+
+    auto t_coll = std::chrono::high_resolution_clock::now();
+
+    // Calculate the relevant avoidances in parallel as far as possible
+    {
+        tbb::task_group task_group;
+        task_group.run([this, relevant_avoidance_radiis]{ calculateAvoidance(relevant_avoidance_radiis, true, m_support_rests_on_model); });
+        task_group.run([this, relevant_avoidance_radiis]{ calculateWallRestrictions(relevant_avoidance_radiis); });
+        task_group.wait();
+    }
+    auto t_end = std::chrono::high_resolution_clock::now();
+    auto dur_col = 0.001 * std::chrono::duration_cast<std::chrono::microseconds>(t_coll - t_start).count();
+    auto dur_avo = 0.001 * std::chrono::duration_cast<std::chrono::microseconds>(t_end - t_coll).count();
+
+//    m_precalculated = true;
+    BOOST_LOG_TRIVIAL(info) << "Precalculating collision took" << dur_col << " ms. Precalculating avoidance took " << dur_avo << " ms.";
+}
+
+const Polygons& TreeModelVolumes::getCollision(const coord_t orig_radius, LayerIndex layer_idx, bool min_xy_dist) const
+{
+    const coord_t radius = this->ceilRadius(orig_radius, min_xy_dist);
+    if (std::optional<std::reference_wrapper<const Polygons>> result = m_collision_cache.getArea({ radius, layer_idx }); result)
+        return result.value().get();
+    if (m_precalculated) {
+        BOOST_LOG_TRIVIAL(error_level_not_in_cache) << "Had to calculate collision at radius " << radius << " and layer " << layer_idx << ", but precalculate was called. Performance may suffer!";
+        TreeSupport::showError("Not precalculated Collision requested.", false);
+    }
+    const_cast<TreeModelVolumes*>(this)->calculateCollision(radius, layer_idx);
+    return getCollision(orig_radius, layer_idx, min_xy_dist);
+}
+
+// Private. Only called internally by calculateAvoidance() and calculateAvoidanceToModel(), radius is already snapped to grid.
+const Polygons& TreeModelVolumes::getCollisionHolefree(coord_t radius, LayerIndex layer_idx) const
+{
+    assert(radius == this->ceilRadius(radius));
+    assert(radius < m_increase_until_radius + m_current_min_xy_dist_delta);
+    if (std::optional<std::reference_wrapper<const Polygons>> result = m_collision_cache_holefree.getArea({ radius, layer_idx }); result)
+        return result.value().get();
+    if (m_precalculated) {
+        BOOST_LOG_TRIVIAL(error_level_not_in_cache) << "Had to calculate collision holefree at radius " << radius << " and layer " << layer_idx << ", but precalculate was called. Performance may suffer!";
+        TreeSupport::showError("Not precalculated Holefree Collision requested.", false);
+    }
+    const_cast<TreeModelVolumes*>(this)->calculateCollisionHolefree({ radius, layer_idx });
+    return getCollisionHolefree(radius, layer_idx);
+}
+
+const Polygons& TreeModelVolumes::getAvoidance(const coord_t orig_radius, LayerIndex layer_idx, AvoidanceType type, bool to_model, bool min_xy_dist) const
+{
+    if (layer_idx == 0) // What on the layer directly above buildplate do i have to avoid to reach the buildplate ...
+        return getCollision(orig_radius, layer_idx, min_xy_dist);
+
+    const coord_t radius = this->ceilRadius(orig_radius, min_xy_dist);
+    if (type == AvoidanceType::FastSafe && radius >= m_increase_until_radius + m_current_min_xy_dist_delta)
+        // no holes anymore by definition at this request
+        type = AvoidanceType::Fast;
+
+    if (std::optional<std::reference_wrapper<const Polygons>> result = 
+            this->avoidance_cache(type, to_model).getArea({ radius, layer_idx }); 
+        result)
+        return result.value().get();
+
+    if (m_precalculated) {
+        if (to_model) {
+            BOOST_LOG_TRIVIAL(error_level_not_in_cache) << "Had to calculate Avoidance to model at radius " << radius << " and layer " << layer_idx << ", but precalculate was called. Performance may suffer!";
+            TreeSupport::showError("Not precalculated Avoidance(to model) requested.", false);
+        } else {
+            BOOST_LOG_TRIVIAL(error_level_not_in_cache) << "Had to calculate Avoidance at radius " << radius << " and layer " << layer_idx << ", but precalculate was called. Performance may suffer!";
+            TreeSupport::showError("Not precalculated Avoidance(to buildplate) requested.", false);
+        }
+    }
+    const_cast<TreeModelVolumes*>(this)->calculateAvoidance({ radius, layer_idx }, ! to_model, to_model);
+    // Retrive failed and correct result was calculated. Now it has to be retrived.
+    return getAvoidance(orig_radius, layer_idx, type, to_model, min_xy_dist);
+}
+
+const Polygons& TreeModelVolumes::getPlaceableAreas(const coord_t orig_radius, LayerIndex layer_idx) const
+{
+    if (orig_radius == 0)
+        return this->getCollision(0, layer_idx, true);
+
+    const coord_t radius = ceilRadius(orig_radius);
+    if (std::optional<std::reference_wrapper<const Polygons>> result = m_placeable_areas_cache.getArea({ radius, layer_idx }); result)
+        return result.value().get();
+    if (m_precalculated) {
+        BOOST_LOG_TRIVIAL(error_level_not_in_cache) << "Had to calculate Placeable Areas at radius " << radius << " and layer " << layer_idx << ", but precalculate was called. Performance may suffer!";
+        TreeSupport::showError("Not precalculated Placeable areas requested.", false);
+    }
+    const_cast<TreeModelVolumes*>(this)->calculatePlaceables(radius, layer_idx);
+    return getPlaceableAreas(orig_radius, layer_idx);
+}
+
+const Polygons& TreeModelVolumes::getWallRestriction(const coord_t orig_radius, LayerIndex layer_idx, bool min_xy_dist) const
+{
+    assert(layer_idx > 0);
+    if (layer_idx == 0) 
+        // Should never be requested as there will be no going below layer 0 ..., 
+        // but just to be sure some semi-sane catch. Alternative would be empty Polygon.
+        return getCollision(orig_radius, layer_idx, min_xy_dist);
+
+    min_xy_dist &= m_current_min_xy_dist_delta > 0;
+
+    const coord_t radius = ceilRadius(orig_radius);
+    if (std::optional<std::reference_wrapper<const Polygons>> result = 
+        (min_xy_dist ? m_wall_restrictions_cache_min : m_wall_restrictions_cache).getArea({ radius, layer_idx });
+        result)
+        return result.value().get();
+    if (m_precalculated) {
+        BOOST_LOG_TRIVIAL(error_level_not_in_cache) << "Had to calculate Wall restricions at radius " << radius << " and layer " << layer_idx << ", but precalculate was called. Performance may suffer!";
+        TreeSupport::showError(
+            min_xy_dist ? 
+                "Not precalculated Wall restriction of minimum xy distance requested )." :
+                "Not precalculated Wall restriction requested )."
+            , false);
+    }
+    const_cast<TreeModelVolumes*>(this)->calculateWallRestrictions({ radius, layer_idx });
+    return getWallRestriction(orig_radius, layer_idx, min_xy_dist); // Retrieve failed and correct result was calculated. Now it has to be retrieved.
+}
+
+void TreeModelVolumes::calculateCollision(const std::vector<RadiusLayerPair> &keys)
+{
+    tbb::parallel_for(tbb::blocked_range<size_t>(0, keys.size()),
+        [&](const tbb::blocked_range<size_t> &range) {
+        for (size_t ikey = range.begin(); ikey != range.end(); ++ ikey) {
+            const LayerIndex radius        = keys[ikey].first;
+            const size_t     max_layer_idx = keys[ikey].second;
+            // recursive call to parallel_for.
+            calculateCollision(radius, max_layer_idx);
+        }
+    });
+}
+
+void TreeModelVolumes::calculateCollision(const coord_t radius, const LayerIndex max_layer_idx)
+{
+    assert(radius == this->ceilRadius(radius));
+
+    // Process the outlines from least layers to most layers so that the final union will run over the longest vector.
+    std::vector<size_t> layer_outline_indices(m_layer_outlines.size(), 0);
+    std::iota(layer_outline_indices.begin(), layer_outline_indices.end(), 0);
+    std::sort(layer_outline_indices.begin(), layer_outline_indices.end(),
+        [this](size_t i, size_t j) { return m_layer_outlines[i].second.size() < m_layer_outlines[j].second.size(); });
+
+    const LayerIndex            min_layer_last = m_collision_cache.getMaxCalculatedLayer(radius);
+    std::vector<Polygons>       data(max_layer_idx + 1 - min_layer_last, Polygons{});
+    const bool                  calculate_placable = m_support_rests_on_model && radius == 0;
+    std::vector<Polygons>       data_placeable;
+    if (calculate_placable)
+        data_placeable = std::vector<Polygons>(max_layer_idx + 1 - min_layer_last, Polygons{});
+
+    for (size_t outline_idx : layer_outline_indices)
+        if (const std::vector<Polygons> &outlines = m_layer_outlines[outline_idx].second; ! outlines.empty()) {
+            const TreeSupportMeshGroupSettings  &settings = m_layer_outlines[outline_idx].first;
+            const coord_t       layer_height              = settings.layer_height;
+            const bool          support_rests_on_model    = ! settings.support_material_buildplate_only;
+            const coord_t       z_distance_bottom         = settings.support_bottom_distance;
+            const int           z_distance_bottom_layers  = round_up_divide<int>(z_distance_bottom, layer_height);
+            const int           z_distance_top_layers     = round_up_divide<int>(settings.support_top_distance, layer_height);
+            const LayerIndex    max_required_layer        = std::min<LayerIndex>(outlines.size(), max_layer_idx + std::max(coord_t(1), z_distance_top_layers));
+            const LayerIndex    min_layer_bottom          = std::max<LayerIndex>(0, min_layer_last - int(z_distance_bottom_layers));
+            // technically this causes collision for the normal xy_distance to be larger by m_current_min_xy_dist_delta for all 
+            // not currently processing meshes as this delta will be added at request time.
+            // avoiding this would require saving each collision for each outline_idx separately.
+            // and later for each avoidance... But avoidance calculation has to be for the whole scene and can NOT be done for each outline_idx separately and combined later.
+            // so avoiding this inaccuracy seems infeasible as it would require 2x the avoidance calculations => 0.5x the performance.
+            const coord_t       xy_distance               = outline_idx == m_current_outline_idx ? m_current_min_xy_dist : settings.support_xy_distance;
+
+            // 1) Calculate offsets of collision areas in parallel.
+            std::vector<Polygons> collision_areas_offsetted(max_required_layer + 1 - min_layer_bottom);
+            tbb::parallel_for(tbb::blocked_range<LayerIndex>(min_layer_bottom, max_required_layer + 1),
+                [&outlines, &machine_border = m_machine_border, offset_value = radius + xy_distance, min_layer_bottom, &collision_areas_offsetted]
+                (const tbb::blocked_range<LayerIndex> &range) {
+                for (LayerIndex layer_idx = range.begin(); layer_idx != range.end(); ++ layer_idx) {
+                    Polygons collision_areas = machine_border;
+                    append(collision_areas, outlines[layer_idx]);
+                    // jtRound is not needed here, as the overshoot can not cause errors in the algorithm, because no assumptions are made about the model.
+                    // if a key does not exist when it is accessed it is added!
+                    collision_areas_offsetted[layer_idx - min_layer_bottom] = offset_value == 0 ? union_(collision_areas) : offset(union_ex(collision_areas), offset_value, ClipperLib::jtMiter, 1.2);
+                }
+            });
+
+            // 2) Sum over top / bottom ranges.
+            const bool last = outline_idx == layer_outline_indices.size();
+            tbb::parallel_for(tbb::blocked_range<LayerIndex>(min_layer_last + 1, max_layer_idx + 1),
+                [&collision_areas_offsetted, &anti_overhang = m_anti_overhang, min_layer_bottom, radius, z_distance_bottom_layers, z_distance_top_layers, min_resolution = m_min_resolution, &data, min_layer_last, last]
+            (const tbb::blocked_range<LayerIndex>& range) {
+                    for (LayerIndex layer_idx = range.begin(); layer_idx != range.end(); ++layer_idx) {
+                        Polygons collisions;
+                        for (int i = -z_distance_bottom_layers; i <= z_distance_top_layers; ++ i) {
+                            int j = layer_idx + i - min_layer_bottom;
+                            if (j >= 0 && j < collision_areas_offsetted.size())
+                                append(collisions, collision_areas_offsetted[j]);
+                        }
+                        collisions = last && layer_idx < anti_overhang.size() ? union_(collisions, offset(union_ex(anti_overhang[layer_idx]), radius, ClipperLib::jtMiter, 1.2)) : union_(collisions);
+                        auto &dst = data[layer_idx - (min_layer_last + 1)];
+                        if (last) {
+                            if (! dst.empty())
+                                collisions = union_(collisions, dst);
+                            dst = polygons_simplify(collisions, min_resolution);
+                        } else
+                            append(dst, collisions);
+                    }
+                });
+
+            // 3) Optionally calculate placables.
+            if (calculate_placable) {
+                // Calculating both the collision areas and placable areas.
+                tbb::parallel_for(tbb::blocked_range<LayerIndex>(std::max(min_layer_last + 1, z_distance_bottom_layers + 1), max_layer_idx + 1),
+                    [&collision_areas_offsetted, &anti_overhang = m_anti_overhang, min_layer_bottom, radius, z_distance_bottom_layers, z_distance_top_layers, last, min_resolution = m_min_resolution, &data_placeable, min_layer_last]
+                (const tbb::blocked_range<LayerIndex>& range) {
+                    for (LayerIndex layer_idx = range.begin(); layer_idx != range.end(); ++ layer_idx) {
+                        LayerIndex layer_idx_below = layer_idx - (z_distance_bottom_layers + 1) - min_layer_bottom;
+                        assert(layer_idx_below >= 0);
+                        auto &current = collision_areas_offsetted[layer_idx - min_layer_bottom];
+                        auto &below   = collision_areas_offsetted[layer_idx_below];
+                        auto placable = diff(below, layer_idx < anti_overhang.size() ? union_(current, anti_overhang[layer_idx - (z_distance_bottom_layers + 1)]) : current);
+                        auto &dst     = data_placeable[layer_idx - (min_layer_last + 1)];
+                        if (last) {
+                            if (! dst.empty())
+                                placable = union_(placable, dst);
+                            dst = polygons_simplify(placable, min_resolution);
+                        } else
+                            append(dst, placable);
+                    }
+                });
+            } else {
+                // Calculating just the collision areas.
+            }
+        }
+#ifdef SLIC3R_TREESUPPORTS_PROGRESS
+    {
+        std::lock_guard<std::mutex> critical_section(*m_critical_progress);
+        if (m_precalculated && m_precalculation_progress < TREE_PROGRESS_PRECALC_COLL) {
+            m_precalculation_progress += TREE_PROGRESS_PRECALC_COLL / keys.size();
+            Progress::messageProgress(Progress::Stage::SUPPORT, m_precalculation_progress * m_progress_multiplier + m_progress_offset, TREE_PROGRESS_TOTAL);
+        }
+    }
+#endif
+    m_collision_cache.insert(std::move(data), min_layer_last + 1, radius);
+    if (calculate_placable)
+        m_placeable_areas_cache.insert(std::move(data_placeable), min_layer_last + 1, radius);
+}
+
+void TreeModelVolumes::calculateCollisionHolefree(const std::vector<RadiusLayerPair> &keys)
+{
+    LayerIndex max_layer = 0;
+    for (long long unsigned int i = 0; i < keys.size(); i++)
+        max_layer = std::max(max_layer, keys[i].second);
+
+    tbb::parallel_for(tbb::blocked_range<size_t>(0, max_layer + 1, keys.size()),
+        [&](const tbb::blocked_range<size_t> &range) {
+        RadiusLayerPolygonCacheData data;
+        for (size_t layer_idx = range.begin(); layer_idx < range.end(); ++ layer_idx) {
+            for (RadiusLayerPair key : keys)
+                if (layer_idx <= key.second) {
+                    // Logically increase the collision by m_increase_until_radius
+                    coord_t radius = key.first;
+                    assert(radius == this->ceilRadius(radius));
+                    assert(radius < m_increase_until_radius + m_current_min_xy_dist_delta);
+                    coord_t increase_radius_ceil = ceilRadius(m_increase_until_radius, false) - radius;
+                    assert(increase_radius_ceil > 0);
+                    // this union is important as otherwise holes(in form of lines that will increase to holes in a later step) can get unioned onto the area.
+                    data[RadiusLayerPair(radius, layer_idx)] = polygons_simplify(
+                        offset(union_ex(getCollision(m_increase_until_radius, layer_idx, false)),
+                            5 - increase_radius_ceil, ClipperLib::jtRound, m_min_resolution),
+                        m_min_resolution);
+                }
+        }
+        m_collision_cache_holefree.insert(std::move(data));
+    });
+}
+
+void TreeModelVolumes::calculateAvoidance(const std::vector<RadiusLayerPair> &keys, bool to_build_plate, bool to_model)
+{
+    // For every RadiusLayer pair there are 3 avoidances that have to be calculated.
+    // Prepare tasks for parallelization.
+    struct AvoidanceTask {
+        AvoidanceType   type;
+        coord_t         radius;
+        LayerIndex      max_required_layer;
+        bool            to_model;
+        LayerIndex      start_layer;
+
+        bool slow()     const { return this->type == AvoidanceType::Slow; }
+        bool holefree() const { return this->type == AvoidanceType::FastSafe; }
+    };
+
+    std::vector<AvoidanceTask> avoidance_tasks;
+    avoidance_tasks.reserve((int(to_build_plate) + int(to_model)) * keys.size() * size_t(AvoidanceType::Count));
+
+    for (int iter_idx = 0; iter_idx < 2 * keys.size() * size_t(AvoidanceType::Count); ++ iter_idx) {
+        AvoidanceTask task{
+            AvoidanceType(iter_idx % int(AvoidanceType::Count)),
+            keys[iter_idx / 6].first,  // radius
+            keys[iter_idx / 6].second, // max_layer
+            ((iter_idx / 3) & 1) != 0  // to_model
+        };
+        // Ensure start_layer is at least 1 as if no avoidance was calculated yet getMaxCalculatedLayer() returns -1.
+        task.start_layer = std::max<LayerIndex>(1, 1 + avoidance_cache(task.type, task.to_model).getMaxCalculatedLayer(task.radius));
+        if (task.start_layer > task.max_required_layer) {
+            BOOST_LOG_TRIVIAL(debug) << "Calculation requested for value already calculated?";
+            continue;
+        }
+        if (! task.holefree() || task.radius < m_increase_until_radius + m_current_min_xy_dist_delta)
+            avoidance_tasks.emplace_back(task);
+    }
+
+    tbb::parallel_for(tbb::blocked_range<size_t>(0, avoidance_tasks.size(), 1),
+        [this, &avoidance_tasks](const tbb::blocked_range<size_t> &range) {
+        for (size_t task_idx = range.begin(); task_idx < range.end(); ++ task_idx) {
+            const AvoidanceTask &task = avoidance_tasks[task_idx];
+            assert(! task.holefree() || task.radius < m_increase_until_radius + m_current_min_xy_dist_delta);
+            if (task.to_model)
+                // ensuring Placeableareas are calculated
+                getPlaceableAreas(task.radius, task.max_required_layer);
+            // The following loop propagating avoidance regions bottom up is inherently serial.
+            const bool  collision_holefree = (task.slow() || task.holefree()) && task.radius < m_increase_until_radius + m_current_min_xy_dist_delta;
+            const float max_move           = task.slow() ? m_max_move_slow : m_max_move;
+            // minDist as the delta was already added, also avoidance for layer 0 will return the collision.
+            Polygons    latest_avoidance   = getAvoidance(task.radius, task.start_layer - 1, task.type, task.to_model, true);
+            std::vector<std::pair<RadiusLayerPair, Polygons>> data;
+            data.reserve(task.max_required_layer + 1 - task.start_layer);
+            for (LayerIndex layer_idx = task.start_layer; layer_idx <= task.max_required_layer; ++ layer_idx) {
+                latest_avoidance = union_(
+                    // Propagate avoidance region from the layers below, adjust for allowed tilt of the tree branch.
+                    offset(union_ex(latest_avoidance), -max_move, ClipperLib::jtRound, m_min_resolution),
+                    // Add current layer collisions.
+                    collision_holefree ? getCollisionHolefree(task.radius, layer_idx) : getCollision(task.radius, layer_idx, true));
+                if (task.to_model)
+                    latest_avoidance = diff(latest_avoidance, getPlaceableAreas(task.radius, layer_idx));
+                latest_avoidance = polygons_simplify(latest_avoidance, m_min_resolution);
+                data.emplace_back(RadiusLayerPair{task.radius, layer_idx}, latest_avoidance);
+            }
+#ifdef SLIC3R_TREESUPPORTS_PROGRESS
+            {
+                std::lock_guard<std::mutex> critical_section(*m_critical_progress);
+                if (m_precalculated && m_precalculation_progress < TREE_PROGRESS_PRECALC_COLL + TREE_PROGRESS_PRECALC_AVO) {
+                    m_precalculation_progress += to_model ? 
+                        0.4 * TREE_PROGRESS_PRECALC_AVO / (keys.size() * 3) :
+                        m_support_rests_on_model ? 0.4 : 1 * TREE_PROGRESS_PRECALC_AVO / (keys.size() * 3);
+                    Progress::messageProgress(Progress::Stage::SUPPORT, m_precalculation_progress * m_progress_multiplier + m_progress_offset, TREE_PROGRESS_TOTAL);
+                }
+            }
+#endif
+            avoidance_cache(task.type, task.to_model).insert(std::move(data));
+        }
+    });
+}
+
+
+void TreeModelVolumes::calculatePlaceables(const std::vector<RadiusLayerPair> &keys)
+{
+    tbb::parallel_for(tbb::blocked_range<size_t>(0, keys.size()),
+        [&, keys](const tbb::blocked_range<size_t>& range) {
+            for (size_t key_idx = range.begin(); key_idx < range.end(); ++ key_idx)
+                this->calculatePlaceables(keys[key_idx].first, keys[key_idx].second);
+        });
+}
+
+void TreeModelVolumes::calculatePlaceables(const coord_t radius, const LayerIndex max_required_layer)
+{
+    LayerIndex start_layer = 1 + m_placeable_areas_cache.getMaxCalculatedLayer(radius);
+    if (start_layer > max_required_layer) {
+        BOOST_LOG_TRIVIAL(debug) << "Requested calculation for value already calculated ?";
+        return;
+    }
+
+    std::vector<Polygons> data(max_required_layer + 1 - start_layer, Polygons{});
+
+    if (start_layer == 0)
+        data[0] = diff(m_machine_border, getCollision(radius, 0, true));
+
+    tbb::parallel_for(tbb::blocked_range<LayerIndex>(std::max(1, start_layer), max_required_layer + 1),
+        [this, &data, radius, start_layer](const tbb::blocked_range<LayerIndex>& range) {
+            for (size_t layer_idx = range.begin(); layer_idx < range.end(); ++ layer_idx)
+                data[layer_idx - start_layer] = offset(union_ex(getPlaceableAreas(0, layer_idx)), - radius, jtMiter, 1.2);
+        });
+#ifdef SLIC3R_TREESUPPORTS_PROGRESS
+    {
+        std::lock_guard<std::mutex> critical_section(*m_critical_progress);
+        if (m_precalculated && m_precalculation_progress < TREE_PROGRESS_PRECALC_COLL + TREE_PROGRESS_PRECALC_AVO) {
+            m_precalculation_progress += 0.2 * TREE_PROGRESS_PRECALC_AVO / (keys.size());
+            Progress::messageProgress(Progress::Stage::SUPPORT, m_precalculation_progress * m_progress_multiplier + m_progress_offset, TREE_PROGRESS_TOTAL);
+        }
+    }
+#endif
+    m_placeable_areas_cache.insert(std::move(data), start_layer, radius);
+}
+
+void TreeModelVolumes::calculateWallRestrictions(const std::vector<RadiusLayerPair> &keys)
+{
+    // Wall restrictions are mainly important when they represent actual walls that are printed, and not "just" the configured z_distance, because technically valid placement is no excuse for moving through a wall.
+    // As they exist to prevent accidentially moving though a wall at high speed between layers like thie (x = wall,i = influence area,o= empty space,d = blocked area because of z distance) Assume maximum movement distance is two characters and maximum safe movement distance of one character
+
+    /* Potential issue addressed by the wall restrictions: Influence area may lag through a wall
+     *  layer z+1:iiiiiiiiiiioooo
+     *  layer z+0:xxxxxiiiiiiiooo
+     *  layer z-1:ooooixxxxxxxxxx
+     */
+
+    // The radius for the upper collission has to be 0 as otherwise one may not enter areas that may be forbidden on layer_idx but not one below (c = not an influence area even though it should ):
+    /*
+     *  layer z+1:xxxxxiiiiiioo
+     *  layer z+0:dddddiiiiiiio
+     *  layer z-1:dddocdddddddd
+     */
+    // Also there can not just the collision of the lower layer be used because if it were:
+    /*
+     *  layer z+1:dddddiiiiiiiiiio
+     *  layer z+0:xxxxxddddddddddc
+     *  layer z-1:dddddxxxxxxxxxxc
+     */
+    // Or of the upper layer be used because if it were:
+    /*
+     *  layer z+1:dddddiiiiiiiiiio
+     *  layer z+0:xxxxcddddddddddc
+     *  layer z-1:ddddcxxxxxxxxxxc
+     */
+
+    // And just offseting with maximum movement distance (and not in multiple steps) could cause:
+    /*
+     *  layer z:   oxiiiiiiiiioo
+     *  layer z-1: ixiiiiiiiiiii
+     */
+
+    tbb::parallel_for(tbb::blocked_range<size_t>(0, keys.size()),
+        [&, keys](const tbb::blocked_range<size_t> &range) {
+        for (size_t key_idx = range.begin(); key_idx < range.end(); ++ key_idx) {
+            const coord_t    radius             = keys[key_idx].first;
+            const LayerIndex max_required_layer = keys[key_idx].second;
+            const coord_t    min_layer_bottom   = std::max(1, m_wall_restrictions_cache.getMaxCalculatedLayer(radius));
+            const size_t     buffer_size        = max_required_layer + 1 - min_layer_bottom;
+            std::vector<Polygons> data(buffer_size, Polygons{});
+            std::vector<Polygons> data_min;
+            if (m_current_min_xy_dist_delta > 0)
+                data_min.assign(buffer_size, Polygons{});
+            tbb::parallel_for(tbb::blocked_range<LayerIndex>(min_layer_bottom, max_required_layer + 1),
+                [this, &data, &data_min, radius, min_layer_bottom](const tbb::blocked_range<LayerIndex> &range) {
+                for (size_t layer_idx = range.begin(); layer_idx < range.end(); ++ layer_idx) {
+                    data[layer_idx - min_layer_bottom] = polygons_simplify(
+                        // radius contains m_current_min_xy_dist_delta already if required
+                        intersection(getCollision(0, layer_idx, false), getCollision(radius, layer_idx - 1, true)),
+                        m_min_resolution);
+                    if (! data_min.empty())
+                        data_min[layer_idx - min_layer_bottom] = 
+                            polygons_simplify(
+                                intersection(getCollision(0, layer_idx, true), getCollision(radius, layer_idx - 1, true)),
+                                m_min_resolution);
+                }
+            });
+            m_wall_restrictions_cache.insert(std::move(data), min_layer_bottom, radius);
+            if (! data_min.empty())
+                m_wall_restrictions_cache_min.insert(std::move(data_min), min_layer_bottom, radius);
+        }
+    });
+}
+
+coord_t TreeModelVolumes::ceilRadius(const coord_t radius) const
+{
+    if (radius == 0)
+        return 0;
+
+    coord_t out = m_radius_0;
+    if (radius > m_radius_0) {
+        // generate SUPPORT_TREE_PRE_EXPONENTIAL_STEPS of radiis before starting to exponentially increase them.
+        coord_t initial_radius_delta = SUPPORT_TREE_EXPONENTIAL_THRESHOLD - m_radius_0;
+        auto ignore = [this](coord_t r) { return std::binary_search(m_ignorable_radii.begin(), m_ignorable_radii.end(), r); };
+        if (initial_radius_delta > SUPPORT_TREE_COLLISION_RESOLUTION) {
+            const int num_steps = round_up_divide(initial_radius_delta, SUPPORT_TREE_EXPONENTIAL_THRESHOLD);
+            const int stepsize  = initial_radius_delta / num_steps;
+            out += stepsize;
+            for (auto step = 0; step < num_steps; ++ step) {
+                if (out >= radius && ! ignore(out))
+                    return out;
+                out += stepsize;
+            }
+        } else
+            out += SUPPORT_TREE_COLLISION_RESOLUTION;
+        while (out < radius || ignore(out)) {
+            assert(out * SUPPORT_TREE_EXPONENTIAL_FACTOR > out + SUPPORT_TREE_COLLISION_RESOLUTION);
+            out = out * SUPPORT_TREE_EXPONENTIAL_FACTOR;
+        }
+    }
+    return out;
+}
+
+}

src/libslic3r/TreeModelVolumes.hpp

@@ -0,0 +1,613 @@
+// Tree supports by Thomas Rahm, losely based on Tree Supports by CuraEngine.
+// Original source of Thomas Rahm's tree supports:
+// https://github.com/ThomasRahm/CuraEngine
+//
+// Original CuraEngine copyright:
+// Copyright (c) 2021 Ultimaker B.V.
+// CuraEngine is released under the terms of the AGPLv3 or higher.
+
+#ifndef slic3r_TreeModelVolumes_hpp
+#define slic3r_TreeModelVolumes_hpp
+
+#include <mutex>
+#include <unordered_map>
+#include <unordered_set>
+
+#include <boost/functional/hash.hpp>
+
+#include "Point.hpp"
+#include "Polygon.hpp"
+#include "PrintConfig.hpp"
+
+namespace Slic3r
+{
+
+using LayerIndex = int;
+
+class BuildVolume;
+class PrintObject;
+
+struct TreeSupportMeshGroupSettings {
+    TreeSupportMeshGroupSettings() = default;
+    explicit TreeSupportMeshGroupSettings(const PrintObject &print_object);
+
+/*********************************************************************/
+/* Print parameters, not support specific:                           */
+/*********************************************************************/
+    coord_t                         layer_height                            { scaled<coord_t>(0.15) };
+    // Maximum Deviation (meshfix_maximum_deviation)
+    // The maximum deviation allowed when reducing the resolution for the Maximum Resolution setting. If you increase this, 
+    // the print will be less accurate, but the g-code will be smaller. Maximum Deviation is a limit for Maximum Resolution, 
+    // so if the two conflict the Maximum Deviation will always be held true.
+    coord_t                         resolution                              { scaled<coord_t>(0.025) };
+    // Minimum Feature Size (aka minimum line width)
+    // Minimum thickness of thin features. Model features that are thinner than this value will not be printed, while features thicker 
+    // than the Minimum Feature Size will be widened to the Minimum Wall Line Width.
+    coord_t                         min_feature_size                        { scaled<coord_t>(0.1) };
+
+/*********************************************************************/
+/* General support parameters:                                       */
+/*********************************************************************/
+
+    // Support Overhang Angle
+    // The minimum angle of overhangs for which support is added. At a value of 0° all overhangs are supported, 90° will not provide any support.
+    double                          support_angle                           { 50. * M_PI / 180. };
+    // Support Line Width
+    // Width of a single support structure line.
+    coord_t                         support_line_width                      { scaled<coord_t>(0.4) };
+    // Support Roof Line Width: Width of a single support roof line.
+    coord_t                         support_roof_line_width                 { scaled<coord_t>(0.4) };
+    // Enable Support Floor (aka bottom interfaces)
+    // Generate a dense slab of material between the bottom of the support and the model. This will create a skin between the model and support.
+    bool                            support_bottom_enable                   { false };
+    // Support Floor Thickness
+    // The thickness of the support floors. This controls the number of dense layers that are printed on top of places of a model on which support rests.
+    coord_t                         support_bottom_height                   { scaled<coord_t>(1.) };
+    bool                            support_material_buildplate_only        { false };
+    // Support Distance Priority
+    // Whether the Support X/Y Distance overrides the Support Z Distance or vice versa. When X/Y overrides Z the X/Y distance can push away 
+    // the support from the model, influencing the actual Z distance to the overhang. We can disable this by not applying the X/Y distance around overhangs.
+    bool                            support_xy_overrides_z                  { false };
+    // Support X/Y Distance
+    // Distance of the support structure from the print in the X/Y directions.
+    // minimum: 0, maximum warning: 1.5 * machine_nozzle_tip_outer_diameter
+    coord_t                         support_xy_distance                     { scaled<coord_t>(0.7) };
+    // Minimum Support X/Y Distance
+    // Distance of the support structure from the overhang in the X/Y directions.
+    // minimum_value: 0,  minimum warning": support_xy_distance - support_line_width * 2, maximum warning: support_xy_distance
+    // Used if ! support_xy_overrides_z.
+    coord_t                         support_xy_distance_overhang            { scaled<coord_t>(0.2) };
+    // Support Top Distance
+    // Distance from the top of the support to the print.
+    coord_t                         support_top_distance                    { scaled<coord_t>(0.1) };
+    // Support Bottom Distance
+    // Distance from the print to the bottom of the support.
+    coord_t                         support_bottom_distance                 { scaled<coord_t>(0.1) };
+    //FIXME likely not needed, optimization for clipping of interface layers
+    // When checking where there's model above and below the support, take steps of the given height. Lower values will slice slower, while higher values 
+    // may cause normal support to be printed in some places where there should have been support interface.
+    coord_t                         support_interface_skip_height           { scaled<coord_t>(0.3) };
+    // Support Infill Line Directions
+    // A list of integer line directions to use. Elements from the list are used sequentially as the layers progress and when the end 
+    // of the list is reached, it starts at the beginning again. The list items are separated by commas and the whole list is contained 
+    // in square brackets. Default is an empty list which means use the default angle 0 degrees.
+    std::vector<double>             support_infill_angles                   {};
+    // Enable Support Roof
+    // Generate a dense slab of material between the top of support and the model. This will create a skin between the model and support.
+    bool                            support_roof_enable                     { false };
+    // Support Roof Thickness
+    // The thickness of the support roofs. This controls the amount of dense layers at the top of the support on which the model rests.
+    coord_t                         support_roof_height                     { scaled<coord_t>(1.) };
+    // Minimum Support Roof Area
+    // Minimum area size for the roofs of the support. Polygons which have an area smaller than this value will be printed as normal support.
+    double                          minimum_roof_area                       { scaled<double>(scaled<double>(1.)) };
+    // A list of integer line directions to use. Elements from the list are used sequentially as the layers progress 
+    // and when the end of the list is reached, it starts at the beginning again. The list items are separated
+    // by commas and the whole list is contained in square brackets. Default is an empty list which means
+    // use the default angles (alternates between 45 and 135 degrees if interfaces are quite thick or 90 degrees).
+    std::vector<double>             support_roof_angles                     {};
+    // Support Roof Pattern (aka top interface)
+    // The pattern with which the roofs of the support are printed.
+    SupportMaterialInterfacePattern support_roof_pattern                    { smipAuto };
+    // Support Pattern
+    // The pattern of the support structures of the print. The different options available result in sturdy or easy to remove support.
+    SupportMaterialPattern          support_pattern                         { smpRectilinear };
+    // Support Line Distance
+    // Distance between the printed support structure lines. This setting is calculated by the support density.
+    coord_t                         support_line_spacing                    { scaled<coord_t>(2.66 - 0.4) };
+    // Support Floor Horizontal Expansion
+    // Amount of offset applied to the floors of the support.
+    coord_t                         support_bottom_offset                   { scaled<coord_t>(0.) };
+    // Support Wall Line Count
+    // The number of walls with which to surround support infill. Adding a wall can make support print more reliably 
+    // and can support overhangs better, but increases print time and material used.
+    // tree: 1, zig-zag: 0, concentric: 1
+    int                             support_wall_count                      { 1 };
+    // Support Roof Line Distance
+    // Distance between the printed support roof lines. This setting is calculated by the Support Roof Density, but can be adjusted separately.
+    coord_t                         support_roof_line_distance              { scaled<coord_t>(0.4) };
+    // Minimum Support Area
+    // Minimum area size for support polygons. Polygons which have an area smaller than this value will not be generated.
+    coord_t                         minimum_support_area                    { scaled<coord_t>(0.) };
+    // Minimum Support Floor Area
+    // Minimum area size for the floors of the support. Polygons which have an area smaller than this value will be printed as normal support.
+    coord_t                         minimum_bottom_area                     { scaled<coord_t>(1.0) };
+    // Support Horizontal Expansion
+    // Amount of offset applied to all support polygons in each layer. Positive values can smooth out the support areas and result in more sturdy support.
+    coord_t                         support_offset                          { scaled<coord_t>(0.) };
+
+/*********************************************************************/
+/* Parameters for the Cura tree supports implementation:             */
+/*********************************************************************/
+
+    // Tree Support Maximum Branch Angle
+    // The maximum angle of the branches, when the branches have to avoid the model. Use a lower angle to make them more vertical and more stable. Use a higher angle to be able to have more reach.
+    // minimum: 0, minimum warning: 20, maximum: 89, maximum warning": 85
+    double                          support_tree_angle                      { 60. * M_PI / 180. };
+    // Tree Support Branch Diameter Angle
+    // The angle of the branches' diameter as they gradually become thicker towards the bottom. An angle of 0 will cause the branches to have uniform thickness over their length. 
+    // A bit of an angle can increase stability of the tree support.
+    // minimum: 0, maximum: 89.9999, maximum warning: 15
+    double                          support_tree_branch_diameter_angle      { 5.  * M_PI / 180. };
+    // Tree Support Branch Distance
+    // How far apart the branches need to be when they touch the model. Making this distance small will cause 
+    // the tree support to touch the model at more points, causing better overhang but making support harder to remove.
+    coord_t                         support_tree_branch_distance            { scaled<coord_t>(1.) };
+    // Tree Support Branch Diameter
+    // The diameter of the thinnest branches of tree support. Thicker branches are more sturdy. Branches towards the base will be thicker than this.
+    // minimum: 0.001, minimum warning: support_line_width * 2
+    coord_t                         support_tree_branch_diameter            { scaled<coord_t>(2.) };
+
+/*********************************************************************/
+/* Parameters new to the Thomas Rahm's tree supports implementation: */
+/*********************************************************************/
+
+    // Tree Support Preferred Branch Angle
+    // The preferred angle of the branches, when they do not have to avoid the model. Use a lower angle to make them more vertical and more stable. Use a higher angle for branches to merge faster.
+    // minimum: 0, minimum warning: 10, maximum: support_tree_angle, maximum warning: support_tree_angle-1
+    double                          support_tree_angle_slow                 { 50. * M_PI / 180. };
+    // Tree Support Diameter Increase To Model
+    // The most the diameter of a branch that has to connect to the model may increase by merging with branches that could reach the buildplate.
+    // Increasing this reduces print time, but increases the area of support that rests on model
+    // minimum: 0
+    coord_t                         support_tree_max_diameter_increase_by_merges_when_support_to_model { scaled<coord_t>(1.0) };
+    // Tree Support Minimum Height To Model
+    // How tall a branch has to be if it is placed on the model. Prevents small blobs of support. This setting is ignored when a branch is supporting a support roof.
+    // minimum: 0, maximum warning: 5
+    coord_t                         support_tree_min_height_to_model        { scaled<coord_t>(1.0) };
+    // Tree Support Inital Layer Diameter
+    // Diameter every branch tries to achieve when reaching the buildplate. Improves bed adhesion.
+    // minimum: 0, maximum warning: 20
+    coord_t                         support_tree_bp_diameter                { scaled<coord_t>(7.5) };
+    // Tree Support Branch Density
+    // Adjusts the density of the support structure used to generate the tips of the branches. A higher value results in better overhangs,
+    // but the supports are harder to remove. Use Support Roof for very high values or ensure support density is similarly high at the top.
+    // 5%-35%
+    double                          support_tree_top_rate                   { 15. };
+    // Tree Support Tip Diameter
+    // The diameter of the top of the tip of the branches of tree support."
+    // minimum: min_wall_line_width, minimum warning: min_wall_line_width+0.05, maximum_value: support_tree_branch_diameter, value: support_line_width
+    coord_t                         support_tree_tip_diameter               { scaled<coord_t>(0.4) };
+
+    // Support Interface Priority
+    // How support interface and support will interact when they overlap. Currently only implemented for support roof.
+    //enum                           support_interface_priority { support_lines_overwrite_interface_area };
+};
+
+class TreeModelVolumes
+{
+public:
+    TreeModelVolumes() = default;
+    explicit TreeModelVolumes(const PrintObject &print_object, const BuildVolume &build_volume,
+        coord_t max_move, coord_t max_move_slow, size_t current_mesh_idx, double progress_multiplier, 
+        double progress_offset, const std::vector<Polygons> &additional_excluded_areas = {});
+    TreeModelVolumes(TreeModelVolumes&&) = default;
+    TreeModelVolumes& operator=(TreeModelVolumes&&) = default;
+
+    TreeModelVolumes(const TreeModelVolumes&) = delete;
+    TreeModelVolumes& operator=(const TreeModelVolumes&) = delete;
+
+    enum class AvoidanceType
+    {
+        Slow,
+        FastSafe,
+        Fast,
+        Count
+    };
+
+    /*!
+     * \brief Precalculate avoidances and collisions up to max_layer.
+     *
+     * Knowledge about branch angle is used to only calculate avoidances and collisions that may actually be needed.
+     * Not calling precalculate() will cause the class to lazily calculate avoidances and collisions as needed, which will be a lot slower on systems with more then one or two cores!
+     */
+    void precalculate(const coord_t max_layer);
+
+    /*!
+     * \brief Provides the areas that have to be avoided by the tree's branches to prevent collision with the model on this layer.
+     *
+     * The result is a 2D area that would cause nodes of radius \p radius to
+     * collide with the model.
+     *
+     * \param radius The radius of the node of interest
+     * \param layer_idx The layer of interest
+     * \param min_xy_dist Is the minimum xy distance used.
+     * \return Polygons object
+     */
+    const Polygons& getCollision(const coord_t radius, LayerIndex layer_idx, bool min_xy_dist) const;
+
+    /*!
+     * \brief Provides the areas that have to be avoided by the tree's branches
+     * in order to reach the build plate.
+     *
+     * The result is a 2D area that would cause nodes of radius \p radius to
+     * collide with the model or be unable to reach the build platform.
+     *
+     * The input collision areas are inset by the maximum move distance and
+     * propagated upwards.
+     *
+     * \param radius The radius of the node of interest
+     * \param layer_idx The layer of interest
+     * \param type Is the propagation with the maximum move distance slow required.
+     * \param to_model Does the avoidance allow good connections with the model.
+     * \param min_xy_dist is the minimum xy distance used.
+     * \return Polygons object
+     */
+    const Polygons& getAvoidance(coord_t radius, LayerIndex layer_idx, AvoidanceType type, bool to_model, bool min_xy_dist) const;
+    /*!
+     * \brief Provides the area represents all areas on the model where the branch does completely fit on the given layer.
+     * \param radius The radius of the node of interest
+     * \param layer_idx The layer of interest
+     * \return Polygons object
+     */
+    const Polygons& getPlaceableAreas(coord_t radius, LayerIndex layer_idx) const;
+    /*!
+     * \brief Provides the area that represents the walls, as in the printed area, of the model. This is an abstract representation not equal with the outline. See calculateWallRestrictions for better description.
+     * \param radius The radius of the node of interest.
+     * \param layer_idx The layer of interest.
+     * \param min_xy_dist is the minimum xy distance used.
+     * \return Polygons object
+     */
+    const Polygons& getWallRestriction(coord_t radius, LayerIndex layer_idx, bool min_xy_dist) const;
+    /*!
+     * \brief Round \p radius upwards to either a multiple of m_radius_sample_resolution or a exponentially increasing value
+     *
+     *	It also adds the difference between the minimum xy distance and the regular one.
+     *
+     * \param radius The radius of the node of interest
+     * \param min_xy_dist is the minimum xy distance used.
+     * \return The rounded radius
+     */
+    coord_t ceilRadius(const coord_t radius, const bool min_xy_dist) const {
+        assert(radius >= 0);
+        return min_xy_dist ? 
+            this->ceilRadius(radius) :
+            // special case as if a radius 0 is requested it could be to ensure correct xy distance. As such it is beneficial if the collision is as close to the configured values as possible.
+            radius > 0 ? this->ceilRadius(radius + m_current_min_xy_dist_delta) : m_current_min_xy_dist_delta;
+    }
+    /*!
+     * \brief Round \p radius upwards to the maximum that would still round up to the same value as the provided one.
+     *
+     * \param radius The radius of the node of interest
+     * \param min_xy_dist is the minimum xy distance used.
+     * \return The maximum radius, resulting in the same rounding.
+     */
+    coord_t getRadiusNextCeil(coord_t radius, bool min_xy_dist) const {
+        assert(radius > 0);
+        return min_xy_dist ?
+            this->ceilRadius(radius) :
+            this->ceilRadius(radius + m_current_min_xy_dist_delta) - m_current_min_xy_dist_delta;
+    }
+
+private:
+    /*!
+     * \brief Convenience typedef for the keys to the caches
+     */
+    using RadiusLayerPair             = std::pair<coord_t, LayerIndex>;
+    using RadiusLayerPolygonCacheData = std::unordered_map<RadiusLayerPair, Polygons, boost::hash<RadiusLayerPair>>;
+    class RadiusLayerPolygonCache {
+    public:
+        RadiusLayerPolygonCache() = default;
+        RadiusLayerPolygonCache(RadiusLayerPolygonCache &&rhs) : data(std::move(rhs.data)) {}
+        RadiusLayerPolygonCache& operator=(RadiusLayerPolygonCache &&rhs) { data = std::move(rhs.data); return *this; }
+
+        RadiusLayerPolygonCache(const RadiusLayerPolygonCache&) = delete;
+        RadiusLayerPolygonCache& operator=(const RadiusLayerPolygonCache&) = delete;
+
+        void insert(RadiusLayerPolygonCacheData &&in) {
+            std::lock_guard<std::mutex> guard(this->mutex);
+            for (auto& d : in)
+                this->data.emplace(d.first, std::move(d.second));
+        }
+        void insert(std::vector<std::pair<RadiusLayerPair, Polygons>> &&in) {
+            std::lock_guard<std::mutex> guard(this->mutex);
+            for (auto& d : in)
+                this->data.emplace(d.first, std::move(d.second));
+        }
+        // by layer
+        void insert(std::vector<std::pair<coord_t, Polygons>> &&in, coord_t radius) {
+            std::lock_guard<std::mutex> guard(this->mutex);
+            for (auto &d : in)
+                this->data.emplace(RadiusLayerPair{ radius, d.first }, std::move(d.second));
+        }
+        void insert(std::vector<Polygons> &&in, coord_t first_layer_idx, coord_t radius) {
+            std::lock_guard<std::mutex> guard(this->mutex);
+            for (auto &d : in)
+                this->data.emplace(RadiusLayerPair{ radius, first_layer_idx ++ }, std::move(d));
+        }
+        /*!
+         * \brief Checks a cache for a given RadiusLayerPair and returns it if it is found
+         * \param key RadiusLayerPair of the requested areas. The radius will be calculated up to the provided layer.
+         * \return A wrapped optional reference of the requested area (if it was found, an empty optional if nothing was found)
+         */
+        std::optional<std::reference_wrapper<const Polygons>> getArea(const TreeModelVolumes::RadiusLayerPair &key) const {
+            std::lock_guard<std::mutex> guard(this->mutex);
+            const auto it = this->data.find(key);
+            return it == this->data.end() ?
+                std::optional<std::reference_wrapper<const Polygons>>{} : std::optional<std::reference_wrapper<const Polygons>>{ it->second };
+        }
+        /*!
+         * \brief Get the highest already calculated layer in the cache.
+         * \param radius The radius for which the highest already calculated layer has to be found.
+         * \param map The cache in which the lookup is performed.
+         *
+         * \return A wrapped optional reference of the requested area (if it was found, an empty optional if nothing was found)
+         */
+        LayerIndex getMaxCalculatedLayer(coord_t radius) const {
+            std::lock_guard<std::mutex> guard(this->mutex);
+            int max_layer = -1;
+            // the placeable on model areas do not exist on layer 0, as there can not be model below it. As such it may be possible that layer 1 is available, but layer 0 does not exist.
+            if (this->data.find({ radius, 1 }) != this->data.end())
+                max_layer = 1;
+            while (this->data.count(TreeModelVolumes::RadiusLayerPair(radius, max_layer + 1)) > 0)
+                ++ max_layer;
+            return max_layer;
+        }
+
+    private:
+        RadiusLayerPolygonCacheData data;
+        mutable std::mutex          mutex;
+    };
+
+
+    /*!
+     * \brief Provides the areas that have to be avoided by the tree's branches to prevent collision with the model on this layer. Holes are removed.
+     *
+     * The result is a 2D area that would cause nodes of given radius to
+     * collide with the model or be inside a hole.
+     * A Hole is defined as an area, in which a branch with m_increase_until_radius radius would collide with the wall.
+     * minimum xy distance is always used.
+     * \param radius The radius of the node of interest
+     * \param layer_idx The layer of interest
+     * \param min_xy_dist Is the minimum xy distance used.
+     * \return Polygons object
+     */
+    const Polygons& getCollisionHolefree(coord_t radius, LayerIndex layer_idx) const;
+
+    /*!
+     * \brief Round \p radius upwards to either a multiple of m_radius_sample_resolution or a exponentially increasing value
+     *
+     * \param radius The radius of the node of interest
+     */
+    coord_t ceilRadius(const coord_t radius) const;
+
+    /*!
+     * \brief Creates the areas that have to be avoided by the tree's branches to prevent collision with the model on this layer.
+     *
+     * The result is a 2D area that would cause nodes of given radius to
+     * collide with the model. Result is saved in the cache.
+     * \param keys RadiusLayerPairs of all requested areas. Every radius will be calculated up to the provided layer.
+     */
+    void calculateCollision(const std::vector<RadiusLayerPair> &keys);
+    void calculateCollision(const coord_t radius, const LayerIndex max_layer_idx);
+    /*!
+     * \brief Creates the areas that have to be avoided by the tree's branches to prevent collision with the model on this layer. Holes are removed.
+     *
+     * The result is a 2D area that would cause nodes of given radius to
+     * collide with the model or be inside a hole. Result is saved in the cache.
+     * A Hole is defined as an area, in which a branch with m_increase_until_radius radius would collide with the wall.
+     * \param keys RadiusLayerPairs of all requested areas. Every radius will be calculated up to the provided layer.
+     */
+    void calculateCollisionHolefree(const std::vector<RadiusLayerPair> &keys);
+
+    /*!
+     * \brief Creates the areas that have to be avoided by the tree's branches to prevent collision with the model on this layer. Holes are removed.
+     *
+     * The result is a 2D area that would cause nodes of given radius to
+     * collide with the model or be inside a hole. Result is saved in the cache.
+     * A Hole is defined as an area, in which a branch with m_increase_until_radius radius would collide with the wall.
+     * \param key RadiusLayerPairs the requested areas. The radius will be calculated up to the provided layer.
+     */
+    void calculateCollisionHolefree(RadiusLayerPair key)
+    {
+        calculateCollisionHolefree(std::vector<RadiusLayerPair>{ RadiusLayerPair(key) });
+    }
+
+    /*!
+     * \brief Creates the areas that have to be avoided by the tree's branches to prevent collision with the model.
+     *
+     * The result is a 2D area that would cause nodes of radius \p radius to
+     * collide with the model. Result is saved in the cache.
+     * \param keys RadiusLayerPairs of all requested areas. Every radius will be calculated up to the provided layer.
+     */
+    void calculateAvoidance(const std::vector<RadiusLayerPair> &keys, bool to_build_plate, bool to_model);
+
+    /*!
+     * \brief Creates the areas that have to be avoided by the tree's branches to prevent collision with the model.
+     *
+     * The result is a 2D area that would cause nodes of radius \p radius to
+     * collide with the model. Result is saved in the cache.
+     * \param key RadiusLayerPair of the requested areas. It will be calculated up to the provided layer.
+     */
+    void calculateAvoidance(RadiusLayerPair key, bool to_build_plate, bool to_model)
+    {
+        calculateAvoidance(std::vector<RadiusLayerPair>{ RadiusLayerPair(key) }, to_build_plate, to_model);
+    }
+
+    /*!
+     * \brief Creates the areas where a branch of a given radius can be place on the model.
+     * Result is saved in the cache.
+     * \param key RadiusLayerPair of the requested areas. It will be calculated up to the provided layer.
+     */
+    void calculatePlaceables(const coord_t radius, const LayerIndex max_required_layer);
+
+
+    /*!
+     * \brief Creates the areas where a branch of a given radius can be placed on the model.
+     * Result is saved in the cache.
+     * \param keys RadiusLayerPair of the requested areas. The radius will be calculated up to the provided layer.
+     */
+    void calculatePlaceables(const std::vector<RadiusLayerPair> &keys);
+
+    /*!
+     * \brief Creates the areas that can not be passed when expanding an area downwards. As such these areas are an somewhat abstract representation of a wall (as in a printed object).
+     *
+     * These areas are at least xy_min_dist wide. When calculating it is always assumed that every wall is printed on top of another (as in has an overlap with the wall a layer below). Result is saved in the corresponding cache.
+     *
+     * \param keys RadiusLayerPairs of all requested areas. Every radius will be calculated up to the provided layer.
+     */
+    void calculateWallRestrictions(const std::vector<RadiusLayerPair> &keys);
+
+    /*!
+     * \brief Creates the areas that can not be passed when expanding an area downwards. As such these areas are an somewhat abstract representation of a wall (as in a printed object).
+     * These areas are at least xy_min_dist wide. When calculating it is always assumed that every wall is printed on top of another (as in has an overlap with the wall a layer below). Result is saved in the corresponding cache.
+     * \param key RadiusLayerPair of the requested area. It well be will be calculated up to the provided layer.
+     */
+    void calculateWallRestrictions(RadiusLayerPair key)
+    {
+        calculateWallRestrictions(std::vector<RadiusLayerPair>{ RadiusLayerPair(key) });
+    }
+
+    /*!
+     * \brief The maximum distance that the center point of a tree branch may move in consecutive layers if it has to avoid the model.
+     */
+    coord_t m_max_move;
+    /*!
+     * \brief The maximum distance that the centre-point of a tree branch may
+     * move in consecutive layers if it does not have to avoid the model
+     */
+    coord_t m_max_move_slow;
+    /*!
+     * \brief The smallest maximum resolution for simplify
+     */
+    coord_t m_min_resolution;
+
+    bool m_precalculated = false;
+    /*!
+     * \brief The index to access the outline corresponding with the currently processing mesh
+     */
+    size_t m_current_outline_idx;
+    /*!
+     * \brief The minimum required clearance between the model and the tree branches
+     */
+    coord_t m_current_min_xy_dist;
+    /*!
+     * \brief The difference between the minimum required clearance between the model and the tree branches and the regular one.
+     */
+    coord_t m_current_min_xy_dist_delta;
+    /*!
+     * \brief Does at least one mesh allow support to rest on a model.
+     */
+    bool m_support_rests_on_model;
+    /*!
+     * \brief The progress of the precalculate function for communicating it to the progress bar.
+     */
+    coord_t m_precalculation_progress = 0;
+    /*!
+     * \brief The progress multiplier of all values added progress bar.
+     * Required for the progress bar the behave as expected when areas have to be calculated multiple times
+     */
+    double m_progress_multiplier;
+    /*!
+     * \brief The progress offset added to all values communicated to the progress bar.
+     * Required for the progress bar the behave as expected when areas have to be calculated multiple times
+     */
+    double m_progress_offset;
+    /*!
+     * \brief Increase radius in the resulting drawn branches, even if the avoidance does not allow it. Will be cut later to still fit.
+     */
+    coord_t m_increase_until_radius;
+
+    /*!
+     * \brief Polygons representing the limits of the printable area of the
+     * machine
+     */
+    Polygons m_machine_border;
+    /*!
+     * \brief Storage for layer outlines and the corresponding settings of the meshes grouped by meshes with identical setting.
+     */
+    std::vector<std::pair<TreeSupportMeshGroupSettings, std::vector<Polygons>>> m_layer_outlines;
+    /*!
+     * \brief Storage for areas that should be avoided, like support blocker or previous generated trees.
+     */
+    std::vector<Polygons> m_anti_overhang;
+    /*!
+     * \brief Radii that can be ignored by ceilRadius as they will never be requested, sorted.
+     */
+    std::vector<coord_t> m_ignorable_radii;
+
+    /*!
+     * \brief Smallest radius a branch can have. This is the radius of a SupportElement with DTT=0.
+     */
+    coord_t m_radius_0;
+
+    /*!
+     * \brief Caches for the collision, avoidance and areas on the model where support can be placed safely
+     * at given radius and layer indices.
+     */
+    RadiusLayerPolygonCache     m_collision_cache;
+    RadiusLayerPolygonCache     m_collision_cache_holefree;
+    RadiusLayerPolygonCache     m_avoidance_cache;
+    RadiusLayerPolygonCache     m_avoidance_cache_slow;
+    RadiusLayerPolygonCache     m_avoidance_cache_to_model;
+    RadiusLayerPolygonCache     m_avoidance_cache_to_model_slow;
+    RadiusLayerPolygonCache     m_placeable_areas_cache;
+
+    /*!
+     * \brief Caches to avoid holes smaller than the radius until which the radius is always increased, as they are free of holes. 
+     * Also called safe avoidances, as they are safe regarding not running into holes.
+     */
+    RadiusLayerPolygonCache     m_avoidance_cache_holefree;
+    RadiusLayerPolygonCache     m_avoidance_cache_holefree_to_model;
+
+    RadiusLayerPolygonCache& avoidance_cache(const AvoidanceType type, const bool to_model) {
+        if (to_model) {
+            switch (type) {
+            case AvoidanceType::Fast:       return m_avoidance_cache_to_model;
+            case AvoidanceType::Slow:       return m_avoidance_cache_to_model_slow;
+            case AvoidanceType::Count:      assert(false);
+            case AvoidanceType::FastSafe:   return m_avoidance_cache_holefree_to_model;
+            }
+        } else {
+            switch (type) {
+            case AvoidanceType::Fast:       return m_avoidance_cache;
+            case AvoidanceType::Slow:       return m_avoidance_cache_slow;
+            case AvoidanceType::Count:      assert(false);
+            case AvoidanceType::FastSafe:   return m_avoidance_cache_holefree;
+            }
+        }
+        assert(false);
+        return m_avoidance_cache;
+    }
+    const RadiusLayerPolygonCache& avoidance_cache(const AvoidanceType type, const bool to_model) const {
+        return const_cast<TreeModelVolumes*>(this)->avoidance_cache(type, to_model);
+    }
+
+    /*!
+     * \brief Caches to represent walls not allowed to be passed over.
+     */
+    RadiusLayerPolygonCache     m_wall_restrictions_cache;
+
+    // A different cache for min_xy_dist as the maximal safe distance an influence area can be increased(guaranteed overlap of two walls in consecutive layer) 
+    // is much smaller when min_xy_dist is used. This causes the area of the wall restriction to be thinner and as such just using the min_xy_dist wall 
+    // restriction would be slower.    
+    RadiusLayerPolygonCache     m_wall_restrictions_cache_min;
+
+#ifdef SLIC3R_TREESUPPORTS_PROGRESS
+    std::unique_ptr<std::mutex> m_critical_progress { std::make_unique<std::mutex>() };
+#endif // SLIC3R_TREESUPPORTS_PROGRESS
+};
+
+}
+
+#endif //slic3r_TreeModelVolumes_hpp

src/libslic3r/TreeSupport.hpp

@@ -0,0 +1,906 @@
+// Tree supports by Thomas Rahm, losely based on Tree Supports by CuraEngine.
+// Original source of Thomas Rahm's tree supports:
+// https://github.com/ThomasRahm/CuraEngine
+//
+// Original CuraEngine copyright:
+// Copyright (c) 2021 Ultimaker B.V.
+// CuraEngine is released under the terms of the AGPLv3 or higher.
+
+#ifndef slic3r_TreeSupport_hpp
+#define slic3r_TreeSupport_hpp
+
+#include "TreeModelVolumes.hpp"
+#include "Point.hpp"
+
+#include <boost/functional/hash.hpp> // For combining hashes
+
+#include "BoundingBox.hpp"
+#include "Utils.hpp"
+
+ #define TREE_SUPPORT_SHOW_ERRORS
+
+#define SUPPORT_TREE_CIRCLE_RESOLUTION 25 // The number of vertices in each circle.
+
+#ifdef SLIC3R_TREESUPPORTS_PROGRESS
+    // The various stages of the process can be weighted differently in the progress bar.
+    // These weights are obtained experimentally using a small sample size. Sensible weights can differ drastically based on the assumed default settings and model.
+    #define TREE_PROGRESS_TOTAL 10000
+    #define TREE_PROGRESS_PRECALC_COLL TREE_PROGRESS_TOTAL * 0.1
+    #define TREE_PROGRESS_PRECALC_AVO TREE_PROGRESS_TOTAL * 0.4
+    #define TREE_PROGRESS_GENERATE_NODES TREE_PROGRESS_TOTAL * 0.1
+    #define TREE_PROGRESS_AREA_CALC TREE_PROGRESS_TOTAL * 0.3
+    #define TREE_PROGRESS_DRAW_AREAS TREE_PROGRESS_TOTAL * 0.1
+    #define TREE_PROGRESS_GENERATE_BRANCH_AREAS TREE_PROGRESS_DRAW_AREAS / 3
+    #define TREE_PROGRESS_SMOOTH_BRANCH_AREAS TREE_PROGRESS_DRAW_AREAS / 3
+    #define TREE_PROGRESS_FINALIZE_BRANCH_AREAS TREE_PROGRESS_DRAW_AREAS / 3
+#endif // SLIC3R_TREESUPPORTS_PROGRESS
+
+#define SUPPORT_TREE_ONLY_GRACIOUS_TO_MODEL false
+#define SUPPORT_TREE_AVOID_SUPPORT_BLOCKER true
+
+namespace Slic3r
+{
+
+using LayerIndex = int;
+
+static constexpr const double  SUPPORT_TREE_EXPONENTIAL_FACTOR = 1.5;
+static constexpr const coord_t SUPPORT_TREE_EXPONENTIAL_THRESHOLD = scaled<coord_t>(1. * SUPPORT_TREE_EXPONENTIAL_FACTOR);
+static constexpr const coord_t SUPPORT_TREE_COLLISION_RESOLUTION = scaled<coord_t>(0.5);
+
+//FIXME
+class Print;
+class PrintObject;
+class SupportGeneratorLayer;
+using SupportGeneratorLayerStorage	= std::deque<SupportGeneratorLayer>;
+using SupportGeneratorLayersPtr		= std::vector<SupportGeneratorLayer*>;
+/*!
+ * \brief Generates a tree structure to support your models.
+ */
+
+class TreeSupport
+{
+public:
+    using AvoidanceType = TreeModelVolumes::AvoidanceType;
+    enum class InterfacePreference
+    {
+        INTERFACE_AREA_OVERWRITES_SUPPORT,
+        SUPPORT_AREA_OVERWRITES_INTERFACE,
+        INTERFACE_LINES_OVERWRITE_SUPPORT,
+        SUPPORT_LINES_OVERWRITE_INTERFACE,
+        NOTHING
+    };
+
+    /*!
+     * \brief Creates an instance of the tree support generator.
+     */
+    TreeSupport() = default;
+
+    /*!
+     * \brief Create the areas that need support.
+     *
+     * These areas are stored inside the given SliceDataStorage object.
+     * \param storage The data storage where the mesh data is gotten from and
+     * where the resulting support areas are stored.
+     */
+    void generateSupportAreas(Print &print, const BuildVolume &build_volume, const std::vector<size_t>& print_object_ids);
+    void generateSupportAreas(PrintObject &print_object);
+
+
+    //todo Remove! Only relevant for public BETA!
+    static bool inline showed_critical=false;
+    static bool inline showed_performance=false;
+    static void showError(std::string message,bool critical);
+
+    struct TreeSupportSettings; // forward declaration as we need some config values in the merge case
+
+    struct AreaIncreaseSettings
+    {
+        AvoidanceType   type                { AvoidanceType::Fast };
+        coord_t         increase_speed      { 0 };
+        bool            increase_radius     { false };
+        bool            no_error            { false };
+        bool            use_min_distance    { false };
+        bool            move                { false };
+        bool operator==(const AreaIncreaseSettings& other) const
+        {
+            return increase_radius == other.increase_radius && increase_speed == other.increase_speed && type == other.type && 
+                   no_error == other.no_error && use_min_distance == other.use_min_distance && move == other.move;
+        }
+    };
+
+    struct SupportElement
+    {
+        explicit SupportElement(
+            coord_t distance_to_top, size_t target_height, Point target_position, bool to_buildplate, bool to_model_gracious, bool use_min_xy_dist, size_t dont_move_until, 
+            bool supports_roof, bool can_use_safe_radius, bool force_tips_to_roof, bool skip_ovalisation) : 
+            target_height(target_height), target_position(target_position), next_position(target_position), next_height(target_height), effective_radius_height(distance_to_top), 
+            to_buildplate(to_buildplate), distance_to_top(distance_to_top), area(nullptr), result_on_layer(target_position), increased_to_model_radius(0), to_model_gracious(to_model_gracious), 
+            elephant_foot_increases(0), use_min_xy_dist(use_min_xy_dist), supports_roof(supports_roof), dont_move_until(dont_move_until), can_use_safe_radius(can_use_safe_radius), 
+            last_area_increase(AreaIncreaseSettings{ AvoidanceType::Fast, 0, false, false, false, false }), missing_roof_layers(force_tips_to_roof ? dont_move_until : 0), skip_ovalisation(skip_ovalisation)
+        {
+        }
+
+
+        explicit SupportElement(const SupportElement& elem, Polygons* newArea = nullptr)
+            : // copy constructor with possibility to set a new area
+              target_height(elem.target_height),
+              target_position(elem.target_position),
+              next_position(elem.next_position),
+              next_height(elem.next_height),
+              effective_radius_height(elem.effective_radius_height),
+              to_buildplate(elem.to_buildplate),
+              distance_to_top(elem.distance_to_top),
+              area(newArea != nullptr ? newArea : elem.area),
+              result_on_layer(elem.result_on_layer),
+              increased_to_model_radius(elem.increased_to_model_radius),
+              to_model_gracious(elem.to_model_gracious),
+              elephant_foot_increases(elem.elephant_foot_increases),
+              use_min_xy_dist(elem.use_min_xy_dist),
+              supports_roof(elem.supports_roof),
+              dont_move_until(elem.dont_move_until),
+              can_use_safe_radius(elem.can_use_safe_radius),
+              last_area_increase(elem.last_area_increase),
+              missing_roof_layers(elem.missing_roof_layers),
+              skip_ovalisation(elem.skip_ovalisation)
+
+        {
+            parents.insert(parents.begin(), elem.parents.begin(), elem.parents.end());
+        }
+
+        /*!
+         * \brief Create a new Element for one layer below the element of the pointer supplied.
+         */
+
+        explicit SupportElement(SupportElement* element_above)
+            : target_height(element_above->target_height),
+              target_position(element_above->target_position),
+              next_position(element_above->next_position),
+              next_height(element_above->next_height),
+              effective_radius_height(element_above->effective_radius_height),
+              to_buildplate(element_above->to_buildplate),
+              distance_to_top(element_above->distance_to_top + 1),
+              area(element_above->area),
+              result_on_layer(Point(-1, -1)), // set to invalid as we are a new node on a new layer
+              increased_to_model_radius(element_above->increased_to_model_radius),
+              to_model_gracious(element_above->to_model_gracious),
+              elephant_foot_increases(element_above->elephant_foot_increases),
+              use_min_xy_dist(element_above->use_min_xy_dist),
+              supports_roof(element_above->supports_roof),
+              dont_move_until(element_above->dont_move_until),
+              can_use_safe_radius(element_above->can_use_safe_radius),
+              last_area_increase(element_above->last_area_increase),
+              missing_roof_layers(element_above->missing_roof_layers),
+              skip_ovalisation(false)
+        {
+            parents = { element_above };
+        }
+
+        // ONLY to be called in merge as it assumes a few assurances made by it.
+        explicit SupportElement(
+            const SupportElement& first, const SupportElement& second, size_t next_height, Point next_position, 
+            coord_t increased_to_model_radius, const TreeSupportSettings& config) : 
+            next_position(next_position), next_height(next_height), area(nullptr), increased_to_model_radius(increased_to_model_radius), 
+            use_min_xy_dist(first.use_min_xy_dist || second.use_min_xy_dist), supports_roof(first.supports_roof || second.supports_roof), 
+            dont_move_until(std::max(first.dont_move_until, second.dont_move_until)), can_use_safe_radius(first.can_use_safe_radius || second.can_use_safe_radius), 
+            missing_roof_layers(std::min(first.missing_roof_layers, second.missing_roof_layers)), skip_ovalisation(false)
+
+        {
+            if (first.target_height > second.target_height) {
+                target_height = first.target_height;
+                target_position = first.target_position;
+            } else {
+                target_height = second.target_height;
+                target_position = second.target_position;
+            }
+            effective_radius_height = std::max(first.effective_radius_height, second.effective_radius_height);
+            distance_to_top = std::max(first.distance_to_top, second.distance_to_top);
+
+            to_buildplate = first.to_buildplate && second.to_buildplate;
+            to_model_gracious = first.to_model_gracious && second.to_model_gracious; // valid as we do not merge non-gracious with gracious
+
+            AddParents(first.parents);
+            AddParents(second.parents);
+
+            elephant_foot_increases = 0;
+            if (config.diameter_scale_bp_radius > 0) {
+                coord_t foot_increase_radius = std::abs(std::max(config.getCollisionRadius(second), config.getCollisionRadius(first)) - config.getCollisionRadius(*this));
+                // elephant_foot_increases has to be recalculated, as when a smaller tree with a larger elephant_foot_increases merge with a larger branch 
+                // the elephant_foot_increases may have to be lower as otherwise the radius suddenly increases. This results often in a non integer value.
+                elephant_foot_increases = foot_increase_radius / (config.branch_radius * (config.diameter_scale_bp_radius - config.diameter_angle_scale_factor));
+            }
+
+            // set last settings to the best out of both parents. If this is wrong, it will only cause a small performance penalty instead of weird behavior.
+            last_area_increase = {
+                std::min(first.last_area_increase.type, second.last_area_increase.type),
+                std::min(first.last_area_increase.increase_speed, second.last_area_increase.increase_speed),
+                first.last_area_increase.increase_radius || second.last_area_increase.increase_radius,
+                first.last_area_increase.no_error || second.last_area_increase.no_error,
+                first.last_area_increase.use_min_distance && second.last_area_increase.use_min_distance,
+                first.last_area_increase.move || second.last_area_increase.move };
+        }
+
+        /*!
+         * \brief The layer this support elements wants reach
+         */
+        LayerIndex target_height;
+
+        /*!
+         * \brief The position this support elements wants to support on layer=target_height
+         */
+        Point target_position;
+
+        /*!
+         * \brief The next position this support elements wants to reach. NOTE: This is mainly a suggestion regarding direction inside the influence area.
+         */
+        Point next_position;
+
+
+        /*!
+         * \brief The next height this support elements wants to reach
+         */
+        LayerIndex next_height;
+
+        /*!
+         * \brief The Effective distance to top of this element regarding radius increases and collision calculations.
+         */
+
+        size_t effective_radius_height;
+
+        /*!
+         * \brief The element trys to reach the buildplate
+         */
+
+        bool to_buildplate;
+
+        /*!
+         * \brief All elements in the layer above the current one that are supported by this element
+         */
+        std::vector<SupportElement*> parents;
+
+        /*!
+         * \brief The amount of layers this element is below the topmost layer of this branch.
+         */
+        size_t distance_to_top;
+
+        /*!
+         * \brief The resulting influence area.
+         * Will only be set in the results of createLayerPathing, and will be nullptr inside!
+         */
+        Polygons* area;
+
+        /*!
+         * \brief The resulting center point around which a circle will be drawn later.
+         * Will be set by setPointsOnAreas
+         */
+        Point result_on_layer = Point(-1, -1);
+        /*!
+         * \brief The amount of extra radius we got from merging branches that could have reached the buildplate, but merged with ones that can not.
+         */
+        coord_t increased_to_model_radius; // how much to model we increased only relevant for merging
+        /*!
+         * \brief Will the branch be able to rest completely on a flat surface, be it buildplate or model ?
+         */
+        bool to_model_gracious;
+
+        /*!
+         * \brief Counter about the times the elephant foot was increased. Can be fractions for merge reasons.
+         */
+        double elephant_foot_increases;
+
+        /*!
+         * \brief Whether the min_xy_distance can be used to get avoidance or similar. Will only be true if support_xy_overrides_z=Z overrides X/Y.
+         */
+        bool use_min_xy_dist;
+
+        /*!
+         * \brief True if this Element or any parent provides support to a support roof.
+         */
+        bool supports_roof;
+
+        /*!
+         * \brief The element trys not to move until this dtt is reached, is set to 0 if the element had to move.
+         */
+        size_t dont_move_until;
+
+        /*!
+         * \brief An influence area is considered safe when it can use the holefree avoidance <=> It will not have to encounter holes on its way downward.
+         */
+        bool can_use_safe_radius;
+
+        /*!
+         * \brief Settings used to increase the influence area to its current state.
+         */
+        AreaIncreaseSettings last_area_increase;
+
+        /*!
+         * \brief Amount of roof layers that were not yet added, because the branch needed to move.
+         */
+        size_t missing_roof_layers;
+
+        /*!
+         * \brief Skip the ovalisation to parent and children when generating the final circles.
+         */
+        bool skip_ovalisation;
+
+        bool operator==(const SupportElement& other) const
+        {
+            return target_position == other.target_position && target_height == other.target_height;
+        }
+
+        bool operator<(const SupportElement& other) const // true if me < other
+        {
+            return !(*this == other) && !(*this > other);
+        }
+        bool operator>(const SupportElement& other) const
+        {
+            // Doesn't really have to make sense, only required for ordering in maps to ensure deterministic behavior.
+            if (*this == other)
+                return false;
+            if (other.target_height != target_height)
+                return other.target_height < target_height;
+            return other.target_position.x() == target_position.x() ? other.target_position.y() < target_position.y() : other.target_position.x() < target_position.x();
+        }
+
+        void AddParents(const std::vector<SupportElement*>& adding)
+        {
+            for (SupportElement* ptr : adding)
+            {
+                parents.emplace_back(ptr);
+            }
+        }
+    };
+
+    /*!
+     * \brief This struct contains settings used in the tree support. Thanks to this most functions do not need to know of meshes etc. Also makes the code shorter.
+     */
+    struct TreeSupportSettings
+    {
+        TreeSupportSettings() = default; // required for the definition of the config variable in the TreeSupport class.
+
+        explicit TreeSupportSettings(const TreeSupportMeshGroupSettings& mesh_group_settings)
+            : angle(mesh_group_settings.support_tree_angle),
+              angle_slow(mesh_group_settings.support_tree_angle_slow),
+              support_line_width(mesh_group_settings.support_line_width),
+              layer_height(mesh_group_settings.layer_height),
+              branch_radius(mesh_group_settings.support_tree_branch_diameter / 2),
+              min_radius(mesh_group_settings.support_tree_tip_diameter / 2), // The actual radius is 50 microns larger as the resulting branches will be increased by 50 microns to avoid rounding errors effectively increasing the xydistance
+              maximum_move_distance((angle < M_PI / 2.) ? (coord_t)(tan(angle) * layer_height) : std::numeric_limits<coord_t>::max()),
+              maximum_move_distance_slow((angle_slow < M_PI / 2.) ? (coord_t)(tan(angle_slow) * layer_height) : std::numeric_limits<coord_t>::max()),
+              support_bottom_layers(mesh_group_settings.support_bottom_enable ? (mesh_group_settings.support_bottom_height + layer_height / 2) / layer_height : 0),
+              tip_layers(std::max((branch_radius - min_radius) / (support_line_width / 3), branch_radius / layer_height)), // Ensure lines always stack nicely even if layer height is large
+              diameter_angle_scale_factor(sin(mesh_group_settings.support_tree_branch_diameter_angle) * layer_height / branch_radius),
+              max_to_model_radius_increase(mesh_group_settings.support_tree_max_diameter_increase_by_merges_when_support_to_model / 2),
+              min_dtt_to_model(round_up_divide(mesh_group_settings.support_tree_min_height_to_model, layer_height)),
+              increase_radius_until_radius(mesh_group_settings.support_tree_branch_diameter / 2),
+              increase_radius_until_layer(increase_radius_until_radius <= branch_radius ? tip_layers * (increase_radius_until_radius / branch_radius) : (increase_radius_until_radius - branch_radius) / (branch_radius * diameter_angle_scale_factor)),
+              support_rests_on_model(! mesh_group_settings.support_material_buildplate_only),
+              xy_distance(mesh_group_settings.support_xy_distance),
+              bp_radius(mesh_group_settings.support_tree_bp_diameter / 2),
+              diameter_scale_bp_radius(std::min(sin(0.7) * layer_height / branch_radius, 1.0 / (branch_radius / (support_line_width / 2.0)))), // Either 40? or as much as possible so that 2 lines will overlap by at least 50%, whichever is smaller.
+              support_xy_overrides_z(mesh_group_settings.support_xy_overrides_z),
+              xy_min_distance(support_xy_overrides_z ? xy_distance : mesh_group_settings.support_xy_distance_overhang),
+              z_distance_top_layers(round_up_divide(mesh_group_settings.support_top_distance, layer_height)),
+              z_distance_bottom_layers(round_up_divide(mesh_group_settings.support_bottom_distance, layer_height)),
+              performance_interface_skip_layers(round_up_divide(mesh_group_settings.support_interface_skip_height, layer_height)),
+              support_infill_angles(mesh_group_settings.support_infill_angles),
+              support_roof_angles(mesh_group_settings.support_roof_angles),
+              roof_pattern(mesh_group_settings.support_roof_pattern),
+              support_pattern(mesh_group_settings.support_pattern),
+              support_roof_line_width(mesh_group_settings.support_roof_line_width),
+              support_line_spacing(mesh_group_settings.support_line_spacing),
+              support_bottom_offset(mesh_group_settings.support_bottom_offset),
+              support_wall_count(mesh_group_settings.support_wall_count),
+              resolution(mesh_group_settings.resolution),
+              support_roof_line_distance(mesh_group_settings.support_roof_line_distance), // in the end the actual infill has to be calculated to subtract interface from support areas according to interface_preference.
+              settings(mesh_group_settings),
+              min_feature_size(mesh_group_settings.min_feature_size)
+
+
+        {
+            layer_start_bp_radius = (bp_radius - branch_radius) / (branch_radius * diameter_scale_bp_radius);
+
+            // safeOffsetInc can only work in steps of the size xy_min_distance in the worst case => xy_min_distance has to be a bit larger than 0 in this worst case and should be large enough for performance to not suffer extremely
+            // When for all meshes the z bottom and top distance is more than one layer though the worst case is xy_min_distance + min_feature_size
+            // This is not the best solution, but the only one to ensure areas can not lag though walls at high maximum_move_distance.
+            if (has_to_rely_on_min_xy_dist_only)
+                xy_min_distance = std::max(coord_t(100), xy_min_distance); // If set to low rounding errors WILL cause errors. Best to keep it above 25.
+
+            xy_distance = std::max(xy_distance, xy_min_distance);
+
+            // (logic) from getInterfaceAngles in FFFGcodeWriter.
+            auto getInterfaceAngles = [&](std::vector<double>& angles, SupportMaterialInterfacePattern pattern) {
+                if (angles.empty())
+                {
+                    if (pattern == SupportMaterialInterfacePattern::smipConcentric)
+                        angles.push_back(0); // Concentric has no rotation.
+                    /*
+                    else if (pattern == SupportMaterialInterfacePattern::TRIANGLES)
+                        angles.push_back(90); // Triangular support interface shouldn't alternate every layer.
+                    */
+                    else {
+                        if (TreeSupportSettings::some_model_contains_thick_roof) {
+                            // Some roofs are quite thick.
+                            // Alternate between the two kinds of diagonal: / and \ .
+                            angles.push_back(M_PI / 4.);
+                            angles.push_back(3. * M_PI / 4.);
+                        }
+                        if (angles.empty())
+                            angles.push_back(M_PI / 2.); // Perpendicular to support lines.
+                    }
+                }
+            };
+
+            //getInterfaceAngles(support_infill_angles, support_pattern);
+            support_infill_angles = { M_PI / 2. };
+            getInterfaceAngles(support_roof_angles, roof_pattern);
+//            const std::unordered_map<std::string, InterfacePreference> interface_map = { { "support_area_overwrite_interface_area", InterfacePreference::SUPPORT_AREA_OVERWRITES_INTERFACE }, { "interface_area_overwrite_support_area", InterfacePreference::INTERFACE_AREA_OVERWRITES_SUPPORT }, { "support_lines_overwrite_interface_area", InterfacePreference::SUPPORT_LINES_OVERWRITE_INTERFACE }, { "interface_lines_overwrite_support_area", InterfacePreference::INTERFACE_LINES_OVERWRITE_SUPPORT }, { "nothing", InterfacePreference::NOTHING } };
+//            interface_preference = interface_map.at(mesh_group_settings.get<std::string>("support_interface_priority"));
+//FIXME this was the default
+//            interface_preference = InterfacePreference::SUPPORT_LINES_OVERWRITE_INTERFACE;
+            interface_preference = InterfacePreference::SUPPORT_AREA_OVERWRITES_INTERFACE;
+        }
+
+    private:
+        double angle;
+        double angle_slow;
+        std::vector<coord_t> known_z;
+
+    public:
+        // some static variables dependent on other meshes that are not currently processed.
+        // Has to be static because TreeSupportConfig will be used in TreeModelVolumes as this reduces redundancy.
+        inline static bool some_model_contains_thick_roof = false;
+        inline static bool has_to_rely_on_min_xy_dist_only = false;
+        /*!
+         * \brief Width of a single line of support.
+         */
+        coord_t support_line_width;
+        /*!
+         * \brief Height of a single layer
+         */
+        coord_t layer_height;
+        /*!
+         * \brief Radius of a branch when it has left the tip.
+         */
+        coord_t branch_radius;
+        /*!
+         * \brief smallest allowed radius, required to ensure that even at DTT 0 every circle will still be printed
+         */
+        coord_t min_radius;
+        /*!
+         * \brief How far an influence area may move outward every layer at most.
+         */
+        coord_t maximum_move_distance;
+        /*!
+         * \brief How far every influence area will move outward every layer if possible.
+         */
+        coord_t maximum_move_distance_slow;
+        /*!
+         * \brief Amount of bottom layers. 0 if disabled.
+         */
+        size_t support_bottom_layers;
+        /*!
+         * \brief Amount of effectiveDTT increases are required to reach branch radius.
+         */
+        size_t tip_layers;
+        /*!
+         * \brief Factor by which to increase the branch radius.
+         */
+        double diameter_angle_scale_factor;
+        /*!
+         * \brief How much a branch resting on the model may grow in radius by merging with branches that can reach the buildplate.
+         */
+        coord_t max_to_model_radius_increase;
+        /*!
+         * \brief If smaller (in layers) than that, all branches to model will be deleted
+         */
+        size_t min_dtt_to_model;
+        /*!
+         * \brief Increase radius in the resulting drawn branches, even if the avoidance does not allow it. Will be cut later to still fit.
+         */
+        coord_t increase_radius_until_radius;
+        /*!
+         * \brief Same as increase_radius_until_radius, but contains the DTT at which the radius will be reached.
+         */
+        size_t increase_radius_until_layer;
+        /*!
+         * \brief True if the branches may connect to the model.
+         */
+        bool support_rests_on_model;
+        /*!
+         * \brief How far should support be from the model.
+         */
+        coord_t xy_distance;
+        /*!
+         * \brief Radius a branch should have when reaching the buildplate.
+         */
+        coord_t bp_radius;
+        /*!
+         * \brief The layer index at which an increase in radius may be required to reach the bp_radius.
+         */
+        coord_t layer_start_bp_radius;
+        /*!
+         * \brief Factor by which to increase the branch radius to reach the required bp_radius at layer 0. Note that this radius increase will not happen in the tip, to ensure the tip is structurally sound.
+         */
+        double diameter_scale_bp_radius;
+        /*!
+         * \brief Should Z distance override X/Y distance, or the other way around.
+         */
+        bool support_xy_overrides_z;
+        /*!
+         * \brief minimum xy_distance. Only relevant when Z overrides XY, otherwise equal to xy_distance-
+         */
+        coord_t xy_min_distance;
+        /*!
+         * \brief Amount of layers distance required the top of the support to the model
+         */
+        size_t z_distance_top_layers;
+        /*!
+         * \brief Amount of layers distance required from the top of the model to the bottom of a support structure.
+         */
+        size_t z_distance_bottom_layers;
+        /*!
+         * \brief used for performance optimization at the support floor. Should have no impact on the resulting tree.
+         */
+        size_t performance_interface_skip_layers;
+        /*!
+         * \brief User specified angles for the support infill.
+         */
+        std::vector<double> support_infill_angles;
+        /*!
+         * \brief User specified angles for the support roof infill.
+         */
+        std::vector<double> support_roof_angles;
+        /*!
+         * \brief Pattern used in the support roof. May contain non relevant data if support roof is disabled.
+         */
+        SupportMaterialInterfacePattern roof_pattern;
+        /*!
+         * \brief Pattern used in the support infill.
+         */
+        SupportMaterialPattern support_pattern;
+        /*!
+         * \brief Line width of the support roof.
+         */
+        coord_t support_roof_line_width;
+        /*!
+         * \brief Distance between support infill lines.
+         */
+        coord_t support_line_spacing;
+        /*!
+         * \brief Offset applied to the support floor area.
+         */
+        coord_t support_bottom_offset;
+        /*
+         * \brief Amount of walls the support area will have.
+         */
+        int support_wall_count;
+        /*
+         * \brief Maximum allowed deviation when simplifying.
+         */
+        coord_t resolution;
+        /*
+         * \brief Distance between the lines of the roof.
+         */
+        coord_t support_roof_line_distance;
+        /*
+         * \brief How overlaps of an interface area with a support area should be handled.
+         */
+        InterfacePreference interface_preference;
+
+        /*
+         * \brief The infill class wants a settings object. This one will be the correct one for all settings it uses.
+         */
+        TreeSupportMeshGroupSettings settings;
+
+        /*
+         * \brief Minimum thickness of any model features.
+         */
+        coord_t min_feature_size;
+
+      public:
+        bool operator==(const TreeSupportSettings& other) const
+        {
+            return branch_radius == other.branch_radius && tip_layers == other.tip_layers && diameter_angle_scale_factor == other.diameter_angle_scale_factor && layer_start_bp_radius == other.layer_start_bp_radius && bp_radius == other.bp_radius && diameter_scale_bp_radius == other.diameter_scale_bp_radius && min_radius == other.min_radius && xy_min_distance == other.xy_min_distance && // as a recalculation of the collision areas is required to set a new min_radius.
+                   xy_distance - xy_min_distance == other.xy_distance - other.xy_min_distance && // if the delta of xy_min_distance and xy_distance is different the collision areas have to be recalculated.
+                   support_rests_on_model == other.support_rests_on_model && increase_radius_until_layer == other.increase_radius_until_layer && min_dtt_to_model == other.min_dtt_to_model && max_to_model_radius_increase == other.max_to_model_radius_increase && maximum_move_distance == other.maximum_move_distance && maximum_move_distance_slow == other.maximum_move_distance_slow && z_distance_bottom_layers == other.z_distance_bottom_layers && support_line_width == other.support_line_width && 
+                   support_xy_overrides_z == other.support_xy_overrides_z && support_line_spacing == other.support_line_spacing && support_roof_line_width == other.support_roof_line_width && // can not be set on a per-mesh basis currently, so code to enable processing different roof line width in the same iteration seems useless.
+                   support_bottom_offset == other.support_bottom_offset && support_wall_count == other.support_wall_count && support_pattern == other.support_pattern && roof_pattern == other.roof_pattern && // can not be set on a per-mesh basis currently, so code to enable processing different roof patterns in the same iteration seems useless.
+                   support_roof_angles == other.support_roof_angles && support_infill_angles == other.support_infill_angles && increase_radius_until_radius == other.increase_radius_until_radius && support_bottom_layers == other.support_bottom_layers && layer_height == other.layer_height && z_distance_top_layers == other.z_distance_top_layers && resolution == other.resolution && // Infill generation depends on deviation and resolution.
+                   support_roof_line_distance == other.support_roof_line_distance && interface_preference == other.interface_preference
+                   && min_feature_size == other.min_feature_size // interface_preference should be identical to ensure the tree will correctly interact with the roof.
+                   // The infill class now wants the settings object and reads a lot of settings, and as the infill class is used to calculate support roof lines for interface-preference. Not all of these may be required to be identical, but as I am not sure, better safe than sorry
+#if 0
+                    && (interface_preference == InterfacePreference::INTERFACE_AREA_OVERWRITES_SUPPORT || interface_preference == InterfacePreference::SUPPORT_AREA_OVERWRITES_INTERFACE
+                    // Perimeter generator parameters
+                       || 
+                            (settings.get<bool>("fill_outline_gaps") == other.settings.get<bool>("fill_outline_gaps") && 
+                             settings.get<coord_t>("min_bead_width") == other.settings.get<coord_t>("min_bead_width") && 
+                             settings.get<double>("wall_transition_angle") == other.settings.get<double>("wall_transition_angle") && 
+                             settings.get<coord_t>("wall_transition_length") == other.settings.get<coord_t>("wall_transition_length") && 
+                             settings.get<Ratio>("wall_split_middle_threshold") == other.settings.get<Ratio>("wall_split_middle_threshold") && 
+                             settings.get<Ratio>("wall_add_middle_threshold") == other.settings.get<Ratio>("wall_add_middle_threshold") && 
+                             settings.get<int>("wall_distribution_count") == other.settings.get<int>("wall_distribution_count") && 
+                             settings.get<coord_t>("wall_transition_filter_distance") == other.settings.get<coord_t>("wall_transition_filter_distance") && 
+                             settings.get<coord_t>("wall_transition_filter_deviation") == other.settings.get<coord_t>("wall_transition_filter_deviation") && 
+                             settings.get<coord_t>("wall_line_width_x") == other.settings.get<coord_t>("wall_line_width_x") && 
+                             settings.get<int>("meshfix_maximum_extrusion_area_deviation") == other.settings.get<int>("meshfix_maximum_extrusion_area_deviation"))
+                        )
+#endif
+                ;
+        }
+
+
+        /*!
+         * \brief Get the Distance to top regarding the real radius this part will have. This is different from distance_to_top, which is can be used to calculate the top most layer of the branch.
+         * \param elem[in] The SupportElement one wants to know the effectiveDTT
+         * \return The Effective DTT.
+         */
+        [[nodiscard]] inline size_t getEffectiveDTT(const TreeSupport::SupportElement& elem) const
+        {
+            return elem.effective_radius_height < increase_radius_until_layer ? (elem.distance_to_top < increase_radius_until_layer ? elem.distance_to_top : increase_radius_until_layer) : elem.effective_radius_height;
+        }
+
+        /*!
+         * \brief Get the Radius part will have based on numeric values.
+         * \param distance_to_top[in] The effective distance_to_top of the element
+         * \param elephant_foot_increases[in] The elephant_foot_increases of the element.
+         * \return The radius an element with these attributes would have.
+         */
+        [[nodiscard]] inline coord_t getRadius(size_t distance_to_top, const double elephant_foot_increases = 0) const
+        {
+            return (distance_to_top <= tip_layers ? min_radius + (branch_radius - min_radius) * distance_to_top / tip_layers : // tip
+                           branch_radius + // base
+                               branch_radius * (distance_to_top - tip_layers) * diameter_angle_scale_factor)
+                   + // gradual increase
+                   branch_radius * elephant_foot_increases * (std::max(diameter_scale_bp_radius - diameter_angle_scale_factor, 0.0));
+        }
+
+        /*!
+         * \brief Get the Radius, that this element will have.
+         * \param elem[in] The Element.
+         * \return The radius the element has.
+         */
+        [[nodiscard]] inline coord_t getRadius(const TreeSupport::SupportElement& elem) const
+        {
+            return getRadius(getEffectiveDTT(elem), elem.elephant_foot_increases);
+        }
+
+        /*!
+         * \brief Get the collision Radius of this Element. This can be smaller then the actual radius, as the drawAreas will cut off areas that may collide with the model.
+         * \param elem[in] The Element.
+         * \return The collision radius the element has.
+         */
+        [[nodiscard]] inline coord_t getCollisionRadius(const TreeSupport::SupportElement& elem) const
+        {
+            return getRadius(elem.effective_radius_height, elem.elephant_foot_increases);
+        }
+
+        /*!
+         * \brief Get the Radius an element should at least have at a given layer.
+         * \param layer_idx[in] The layer.
+         * \return The radius every element should aim to achieve.
+         */
+        [[nodiscard]] inline coord_t recommendedMinRadius(LayerIndex layer_idx) const
+        {
+            double scale = (layer_start_bp_radius - int(layer_idx)) * diameter_scale_bp_radius;
+            return scale > 0 ? branch_radius + branch_radius * scale : 0;
+        }
+
+        /*!
+         * \brief Return on which z in microns the layer will be printed. Used only for support infill line generation.
+         * \param layer_idx[in] The layer.
+         * \return The radius every element should aim to achieve.
+         */
+        [[nodiscard]] inline coord_t getActualZ(LayerIndex layer_idx)
+        {
+            return layer_idx < coord_t(known_z.size()) ? known_z[layer_idx] : (layer_idx - known_z.size()) * layer_height + known_z.size() ? known_z.back() : 0;
+        }
+
+        /*!
+         * \brief Set the z every Layer is printed at. Required for getActualZ to work
+         * \param z[in] The z every LayerIndex is printed. Vector is used as a map<LayerIndex,coord_t> with the index of each element being the corresponding LayerIndex
+         * \return The radius every element should aim to achieve.
+         */
+        void setActualZ(std::vector<coord_t>& z)
+        {
+            known_z = z;
+        }
+    };
+
+private:
+    /*!
+     * \brief Creates the initial influence areas (that can later be propagated down) by placing them below the overhang.
+     *
+     * Generates Points where the Model should be supported and creates the areas where these points have to be placed.
+     *
+     * \param mesh[in] The mesh that is currently processed.
+     * \param move_bounds[out] Storage for the influence areas.
+     * \param storage[in] Background storage, required for adding roofs.
+     */
+    void generateInitialAreas(const PrintObject &print_object, 
+        const std::vector<Polygons>             &overhangs, 
+        std::vector<std::set<SupportElement*>>  &move_bounds,
+        SupportGeneratorLayersPtr               &top_contacts,
+        SupportGeneratorLayersPtr               &top_interface_layers,
+        SupportGeneratorLayerStorage            &layer_storage);
+
+    /*!
+     * \brief Checks if an influence area contains a valid subsection and returns the corresponding metadata and the new Influence area.
+     *
+     * Calculates an influence areas of the layer below, based on the influence area of one element on the current layer.
+     * Increases every influence area by maximum_move_distance_slow. If this is not enough, as in we would change our gracious or to_buildplate status the influence areas are instead increased by maximum_move_distance_slow.
+     * Also ensures that increasing the radius of a branch, does not cause it to change its status (like to_buildplate ). If this were the case, the radius is not increased instead.
+     *
+     * Warning: The used format inside this is different as the SupportElement does not have a valid area member. Instead this area is saved as value of the dictionary. This was done to avoid not needed heap allocations.
+     *
+     * \param settings[in] Which settings have to be used to check validity.
+     * \param layer_idx[in] Number of the current layer.
+     * \param parent[in] The metadata of the parents influence area.
+     * \param relevant_offset[in] The maximal possible influence area. No guarantee regarding validity with current layer collision required, as it is ensured in-function!
+     * \param to_bp_data[out] The part of the Influence area that can reach the buildplate.
+     * \param to_model_data[out] The part of the Influence area that do not have to reach the buildplate. This has overlap with new_layer_data.
+     * \param increased[out]  Area than can reach all further up support points. No assurance is made that the buildplate or the model can be reached in accordance to the user-supplied settings.
+     * \param overspeed[in] How much should the already offset area be offset again. Usually this is 0.
+     * \param mergelayer[in] Will the merge method be called on this layer. This information is required as some calculation can be avoided if they are not required for merging.
+     * \return A valid support element for the next layer regarding the calculated influence areas. Empty if no influence are can be created using the supplied influence area and settings.
+     */
+    std::optional<TreeSupport::SupportElement> increaseSingleArea(AreaIncreaseSettings settings, LayerIndex layer_idx, SupportElement* parent, const Polygons& relevant_offset, Polygons& to_bp_data, Polygons& to_model_data, Polygons& increased, const coord_t overspeed, const bool mergelayer);
+    /*!
+     * \brief Increases influence areas as far as required.
+     *
+     * Calculates influence areas of the layer below, based on the influence areas of the current layer.
+     * Increases every influence area by maximum_move_distance_slow. If this is not enough, as in it would change the gracious or to_buildplate status, the influence areas are instead increased by maximum_move_distance.
+     * Also ensures that increasing the radius of a branch, does not cause it to change its status (like to_buildplate ). If this were the case, the radius is not increased instead.
+     *
+     * Warning: The used format inside this is different as the SupportElement does not have a valid area member. Instead this area is saved as value of the dictionary. This was done to avoid not needed heap allocations.
+     *
+     * \param to_bp_areas[out] Influence areas that can reach the buildplate
+     * \param to_model_areas[out] Influence areas that do not have to reach the buildplate. This has overlap with new_layer_data, as areas that can reach the buildplate are also considered valid areas to the model.
+     * This redundancy is required if a to_buildplate influence area is allowed to merge with a to model influence area.
+     * \param influence_areas[out] Area than can reach all further up support points. No assurance is made that the buildplate or the model can be reached in accordance to the user-supplied settings.
+     * \param bypass_merge_areas[out] Influence areas ready to be added to the layer below that do not need merging.
+     * \param last_layer[in] Influence areas of the current layer.
+     * \param layer_idx[in] Number of the current layer.
+     * \param mergelayer[in] Will the merge method be called on this layer. This information is required as some calculation can be avoided if they are not required for merging.
+     */
+    void increaseAreas(std::unordered_map<SupportElement, Polygons>& to_bp_areas, std::unordered_map<SupportElement, Polygons>& to_model_areas, std::map<SupportElement, Polygons>& influence_areas, std::vector<SupportElement*>& bypass_merge_areas, const std::vector<SupportElement*>& last_layer, const LayerIndex layer_idx, const bool mergelayer);
+
+    /*!
+     * \brief Propagates influence downwards, and merges overlapping ones.
+     *
+     * \param move_bounds[in,out] All currently existing influence areas
+     */
+    void createLayerPathing(std::vector<std::set<SupportElement*>>& move_bounds);
+
+
+    /*!
+     * \brief Sets the result_on_layer for all parents based on the SupportElement supplied.
+     *
+     * \param elem[in] The SupportElements, which parent's position should be determined.
+     */
+    void setPointsOnAreas(const SupportElement* elem);
+    /*!
+     * \brief Get the best point to connect to the model and set the result_on_layer of the relevant SupportElement accordingly.
+     *
+     * \param move_bounds[in,out] All currently existing influence areas
+     * \param first_elem[in,out] SupportElement that did not have its result_on_layer set meaning that it does not have a child element.
+     * \param layer_idx[in] The current layer.
+     * \return Should elem be deleted.
+     */
+    bool setToModelContact(std::vector<std::set<SupportElement*>>& move_bounds, SupportElement* first_elem, const LayerIndex layer_idx);
+
+    /*!
+     * \brief Set the result_on_layer point for all influence areas
+     *
+     * \param move_bounds[in,out] All currently existing influence areas
+     */
+    void createNodesFromArea(std::vector<std::set<SupportElement*>>& move_bounds);
+
+    /*!
+     * \brief Draws circles around result_on_layer points of the influence areas
+     *
+     * \param linear_data[in] All currently existing influence areas with the layer they are on
+     * \param layer_tree_polygons[out] Resulting branch areas with the layerindex they appear on. layer_tree_polygons.size() has to be at least linear_data.size() as each Influence area in linear_data will save have at least one (that's why it's a vector<vector>) corresponding branch area in layer_tree_polygons.
+     * \param inverse_tree_order[in] A mapping that returns the child of every influence area.
+     */
+    void generateBranchAreas(std::vector<std::pair<LayerIndex, SupportElement*>>& linear_data, std::vector<std::unordered_map<SupportElement*, Polygons>>& layer_tree_polygons, const std::map<SupportElement*, SupportElement*>& inverse_tree_order);
+
+    /*!
+     * \brief Applies some smoothing to the outer wall, intended to smooth out sudden jumps as they can happen when a branch moves though a hole.
+     *
+     * \param layer_tree_polygons[in,out] Resulting branch areas with the layerindex they appear on.
+     */
+    void smoothBranchAreas(std::vector<std::unordered_map<SupportElement*, Polygons>>& layer_tree_polygons);
+
+    /*!
+     * \brief Drop down areas that do rest non-gracefully on the model to ensure the branch actually rests on something.
+     *
+     * \param layer_tree_polygons[in] Resulting branch areas with the layerindex they appear on.
+     * \param linear_data[in] All currently existing influence areas with the layer they are on
+     * \param dropped_down_areas[out] Areas that have to be added to support all non-graceful areas.
+     * \param inverse_tree_order[in] A mapping that returns the child of every influence area.
+     */
+    void dropNonGraciousAreas(std::vector<std::unordered_map<SupportElement*, Polygons>>& layer_tree_polygons, const std::vector<std::pair<LayerIndex, SupportElement*>>& linear_data, std::vector<std::vector<std::pair<LayerIndex, Polygons>>>& dropped_down_areas, const std::map<SupportElement*, SupportElement*>& inverse_tree_order);
+
+    /*!
+     * \brief Generates Support Floor, ensures Support Roof can not cut of branches, and saves the branches as support to storage
+     *
+     * \param support_layer_storage[in] Areas where support should be generated.
+     * \param support_roof_storage[in] Areas where support was replaced with roof.
+     * \param storage[in,out] The storage where the support should be stored.
+     */
+    void finalizeInterfaceAndSupportAreas(
+        const PrintObject               &print_object,
+        const std::vector<Polygons>     &overhangs,
+        std::vector<Polygons>           &support_layer_storage,
+        std::vector<Polygons>           &support_roof_storage,
+
+        SupportGeneratorLayersPtr   	&bottom_contacts,
+        SupportGeneratorLayersPtr   	&top_contacts,
+        SupportGeneratorLayersPtr       &intermediate_layers,
+        SupportGeneratorLayerStorage    &layer_storage);
+
+    /*!
+     * \brief Draws circles around result_on_layer points of the influence areas and applies some post processing.
+     *
+     * \param move_bounds[in] All currently existing influence areas
+     * \param storage[in,out] The storage where the support should be stored.
+     */
+    void drawAreas(
+        PrintObject                             &print_object, 
+        const std::vector<Polygons>             &overhangs,
+        std::vector<std::set<SupportElement*>>  &move_bounds,
+
+        SupportGeneratorLayersPtr            	&bottom_contacts,
+        SupportGeneratorLayersPtr   	        &top_contacts,
+        SupportGeneratorLayersPtr               &intermediate_layers,
+        SupportGeneratorLayerStorage            &layer_storage);
+
+    /*!
+     * \brief Settings with the indexes of meshes that use these settings.
+     *
+     */
+    std::vector<std::pair<TreeSupportSettings, std::vector<size_t>>> m_grouped_meshes;
+
+    /*!
+     * \brief Generator for model collision, avoidance and internal guide volumes.
+     *
+     */
+    TreeModelVolumes m_volumes;
+
+    /*!
+     * \brief Contains config settings to avoid loading them in every function. This was done to improve readability of the code.
+     */
+    TreeSupportSettings m_config;
+
+    /*!
+     * \brief The progress multiplier of all values added progress bar.
+     * Required for the progress bar the behave as expected when areas have to be calculated multiple times
+     */
+    double m_progress_multiplier = 1;
+
+    /*!
+     * \brief The progress offset added to all values communicated to the progress bar.
+     * Required for the progress bar the behave as expected when areas have to be calculated multiple times
+     */
+    double m_progress_offset = 0;
+};
+
+
+} // namespace Slic3r
+
+namespace std
+{
+template <>
+struct hash<Slic3r::TreeSupport::SupportElement>
+{
+    size_t operator()(const Slic3r::TreeSupport::SupportElement& node) const
+    {
+        size_t hash_node = Slic3r::PointHash{}(node.target_position);
+        boost::hash_combine(hash_node, size_t(node.target_height));
+        return hash_node;
+    }
+};
+} // namespace std
+
+#endif /* slic3r_TreeSupport_hpp */

src/libslic3r/Utils.hpp

@@ -192,6 +192,14 @@ inline INDEX_TYPE next_idx_modulo(INDEX_TYPE idx, const INDEX_TYPE count)
 	return idx;
 }
 
+
+// Return dividend divided by divisor rounded to the nearest integer
+template<typename INDEX_TYPE>
+inline INDEX_TYPE round_up_divide(const INDEX_TYPE dividend, const INDEX_TYPE divisor)
+{
+    return (dividend + divisor - 1) / divisor;
+}
+
 template<typename CONTAINER_TYPE>
 inline typename CONTAINER_TYPE::size_type prev_idx_modulo(typename CONTAINER_TYPE::size_type idx, const CONTAINER_TYPE &container) 
 { 

src/libslic3r/libslic3r.h

@@ -345,6 +345,25 @@ constexpr T NaN = std::numeric_limits<T>::quiet_NaN();
 constexpr float NaNf = NaN<float>;
 constexpr double NaNd = NaN<double>;
 
+// Rounding up.
+// 1.5 is rounded to 2
+// 1.49 is rounded to 1
+// 0.5 is rounded to 1,
+// 0.49 is rounded to 0
+// -0.5 is rounded to 0,
+// -0.51 is rounded to -1,
+// -1.5 is rounded to -1.
+// -1.51 is rounded to -2.
+// If input is not a valid float (it is infinity NaN or if it does not fit)
+// the float to int conversion produces a max int on Intel and +-max int on ARM.
+template<typename I>
+inline IntegerOnly<I, I> fast_round_up(double a)
+{
+    // Why does Java Math.round(0.49999999999999994) return 1?
+    // https://stackoverflow.com/questions/9902968/why-does-math-round0-49999999999999994-return-1
+    return a == 0.49999999999999994 ? I(0) : I(floor(a + 0.5));
+}
+
 } // namespace Slic3r
 
 #endif

src/libslic3r/utils.cpp

@@ -129,7 +129,9 @@ void disable_multi_threading()
 {
     // Disable parallelization so the Shiny profiler works
 #ifdef TBB_HAS_GLOBAL_CONTROL
-    tbb::global_control(tbb::global_control::max_allowed_parallelism, 1);
+	{
+		static tbb::global_control gc(tbb::global_control::max_allowed_parallelism, 1);
+	}
 #else // TBB_HAS_GLOBAL_CONTROL
     static tbb::task_scheduler_init *tbb_init = new tbb::task_scheduler_init(1);
     UNUSED(tbb_init);

src/slic3r/GUI/3DScene.cpp

@@ -1648,6 +1648,13 @@ static void thick_lines_to_geometry(
     double width_initial = 0.0;
     double bottom_z_initial = 0.0;
 
+    // Reserve for a smooth path. Likley the path will not be that smooth, but better than nothing.
+    // Allocated 1.5x more data than minimum.
+    // Number of indices, not triangles.
+    geometry.reserve_more_indices((lines.size() * 8 * 3) * 3 / 2);
+    // Number of vertices, not floats.
+    geometry.reserve_more_vertices(((lines.size() + 1) * 4) * 3 / 2);
+
     // loop once more in case of closed loops
     const size_t lines_end = closed ? (lines.size() + 1) : lines.size();
     for (size_t ii = 0; ii < lines_end; ++ii) {

src/slic3r/GUI/GCodeViewer.cpp

@@ -51,7 +51,7 @@ static EMoveType buffer_type(unsigned char id) {
 // Equivalent to conversion to string with sprintf(buf, "%.2g", value) and conversion back to float, but faster.
 static float round_to_bin(const float value)
 {
-//    assert(value > 0);
+//    assert(value >= 0);
     constexpr float const scale    [5] = { 100.f,  1000.f,  10000.f,  100000.f,  1000000.f };
     constexpr float const invscale [5] = { 0.01f,  0.001f,  0.0001f,  0.00001f,  0.000001f };
     constexpr float const threshold[5] = { 0.095f, 0.0095f, 0.00095f, 0.000095f, 0.0000095f };
@@ -59,7 +59,12 @@ static float round_to_bin(const float value)
     int                   i            = 0;
     // While the scaling factor is not yet large enough to get two integer digits after scaling and rounding:
     for (; value < threshold[i] && i < 4; ++ i) ;
-    return std::round(value * scale[i]) * invscale[i];
+    // At least on MSVC std::round() calls a complex function, which is pretty expensive.
+    // our fast_round_up is much cheaper and it could be inlined.
+//    return std::round(value * scale[i]) * invscale[i];
+    double a = value * scale[i];
+    assert(std::abs(a) < double(std::numeric_limits<int64_t>::max()));
+    return fast_round_up<int64_t>(a) * invscale[i];
 }
 
 void GCodeViewer::VBuffer::reset()

src/slic3r/GUI/GLCanvas3D.cpp

@@ -7135,6 +7135,11 @@ void GLCanvas3D::_load_print_object_toolpaths(const PrintObject& print_object, c
         return volume;
     };
     const size_t    volumes_cnt_initial = m_volumes.volumes.size();
+    // Limit the number of threads as the code below does not scale well due to memory pressure.
+    // (most of the time is spent in malloc / free / memmove)
+    // Not using all the threads leaves some of the threads to G-code generator.
+    tbb::task_arena limited_arena(std::min(tbb::this_task_arena::max_concurrency(), 4));
+    limited_arena.execute([&ctxt, grain_size, &new_volume, is_selected_separate_extruder, this]{
     tbb::parallel_for(
         tbb::blocked_range<size_t>(0, ctxt.layers.size(), grain_size),
         [&ctxt, &new_volume, is_selected_separate_extruder, this](const tbb::blocked_range<size_t>& range) {
@@ -7309,6 +7314,7 @@ void GLCanvas3D::_load_print_object_toolpaths(const PrintObject& print_object, c
             vol->indexed_vertex_array.shrink_to_fit();
 #endif // ENABLE_LEGACY_OPENGL_REMOVAL
     });
+    }); // task arena
 
     BOOST_LOG_TRIVIAL(debug) << "Loading print object toolpaths in parallel - finalizing results" << m_volumes.log_memory_info() << log_memory_info();
     // Remove empty volumes from the newly added volumes.

src/slic3r/GUI/GLModel.cpp

@@ -94,22 +94,8 @@ void GLModel::Geometry::add_vertex(const Vec3f& position)
 void GLModel::Geometry::add_vertex(const Vec3f& position, const Vec2f& tex_coord)
 {
     assert(format.vertex_layout == EVertexLayout::P3T2);
-    vertices.emplace_back(position.x());
+    vertices.insert(vertices.end(), position.data(), position.data() + 3);
-    vertices.emplace_back(position.y());
+    vertices.insert(vertices.end(), tex_coord.data(), tex_coord.data() + 2);
-    vertices.emplace_back(position.z());
-    vertices.emplace_back(tex_coord.x());
-    vertices.emplace_back(tex_coord.y());
-}
-
-void GLModel::Geometry::add_vertex(const Vec3f& position, const Vec3f& normal)
-{
-    assert(format.vertex_layout == EVertexLayout::P3N3);
-    vertices.emplace_back(position.x());
-    vertices.emplace_back(position.y());
-    vertices.emplace_back(position.z());
-    vertices.emplace_back(normal.x());
-    vertices.emplace_back(normal.y());
-    vertices.emplace_back(normal.z());
 }
 
 void GLModel::Geometry::add_vertex(const Vec3f& position, const Vec3f& normal, const Vec2f& tex_coord)
@@ -161,13 +147,6 @@ void GLModel::Geometry::add_line(unsigned int id1, unsigned int id2)
     indices.emplace_back(id2);
 }
 
-void GLModel::Geometry::add_triangle(unsigned int id1, unsigned int id2, unsigned int id3)
-{
-    indices.emplace_back(id1);
-    indices.emplace_back(id2);
-    indices.emplace_back(id3);
-}
-
 Vec2f GLModel::Geometry::extract_position_2(size_t id) const
 {
     const size_t p_stride = position_stride_floats(format);

src/slic3r/GUI/GLModel.hpp

@@ -4,6 +4,7 @@
 #include "libslic3r/Point.hpp"
 #include "libslic3r/BoundingBox.hpp"
 #include "libslic3r/Color.hpp"
+#include "libslic3r/Utils.hpp"
 #include <vector>
 #include <string>
 
@@ -90,13 +91,19 @@ namespace GUI {
             ColorRGBA color{ ColorRGBA::BLACK() };
 
             void reserve_vertices(size_t vertices_count) { vertices.reserve(vertices_count * vertex_stride_floats(format)); }
+            void reserve_more_vertices(size_t vertices_count) { vertices.reserve(next_highest_power_of_2(vertices.size() + vertices_count * vertex_stride_floats(format))); }
             void reserve_indices(size_t indices_count) { indices.reserve(indices_count); }
+            void reserve_more_indices(size_t indices_count) { indices.reserve(next_highest_power_of_2(indices.size() + indices_count)); }
 
             void add_vertex(const Vec2f& position);                                              // EVertexLayout::P2
             void add_vertex(const Vec2f& position, const Vec2f& tex_coord);                      // EVertexLayout::P2T2
             void add_vertex(const Vec3f& position);                                              // EVertexLayout::P3
             void add_vertex(const Vec3f& position, const Vec2f& tex_coord);                      // EVertexLayout::P3T2
-            void add_vertex(const Vec3f& position, const Vec3f& normal);                         // EVertexLayout::P3N3
+            void add_vertex(const Vec3f& position, const Vec3f& normal) {                        // EVertexLayout::P3N3
+                assert(format.vertex_layout == EVertexLayout::P3N3);
+                vertices.insert(vertices.end(), position.data(), position.data() + 3);
+                vertices.insert(vertices.end(), normal.data(), normal.data() + 3);
+            }
             void add_vertex(const Vec3f& position, const Vec3f& normal, const Vec2f& tex_coord); // EVertexLayout::P3N3T2
 #if ENABLE_OPENGL_ES
             void add_vertex(const Vec3f& position, const Vec3f& normal, const Vec3f& extra);     // EVertexLayout::P3N3E3
@@ -109,7 +116,11 @@ namespace GUI {
 
             void add_index(unsigned int id);
             void add_line(unsigned int id1, unsigned int id2);
-            void add_triangle(unsigned int id1, unsigned int id2, unsigned int id3);
+            void add_triangle(unsigned int id1, unsigned int id2, unsigned int id3){
+                indices.emplace_back(id1);
+                indices.emplace_back(id2);
+                indices.emplace_back(id3);
+            }
 
             Vec2f extract_position_2(size_t id) const;
             Vec3f extract_position_3(size_t id) const;

tests/libslic3r/CMakeLists.txt

@@ -22,6 +22,7 @@ add_executable(${_TEST_NAME}_tests
 	test_meshboolean.cpp
 	test_marchingsquares.cpp
 	test_timeutils.cpp
+	test_utils.cpp
 	test_voronoi.cpp
     test_optimizers.cpp
     test_png_io.cpp

tests/libslic3r/test_clipper_utils.cpp

@@ -294,7 +294,7 @@ SCENARIO("Various Clipper operations - t/clipper.t", "[ClipperUtils]") {
     
         WHEN("clipping a line") {
             auto line = Polyline::new_scale({ { 152.742,288.086671142818 }, { 152.742,34.166466971035 } });    
-            Polylines intersection = intersection_pl(line, Polygons{ circle_with_hole });
+            Polylines intersection = intersection_pl(line, to_polygons(circle_with_hole));
             THEN("clipped to two pieces") {
                 REQUIRE(intersection.front().length() == Approx((Vec2d(152742000, 215178843) - Vec2d(152742000, 288086661)).norm()));
                 REQUIRE(intersection[1].length() == Approx((Vec2d(152742000, 35166477) - Vec2d(152742000, 108087507)).norm()));

tests/libslic3r/test_utils.cpp

@@ -0,0 +1,35 @@
+#include <catch2/catch.hpp>
+
+#include "libslic3r/libslic3r.h"
+
+SCENARIO("Test fast_round_up()") {
+    using namespace Slic3r;
+
+    THEN("fast_round_up<int>(1.5) is 2") {
+        REQUIRE(fast_round_up<int>(1.5) == 2);
+    }
+    THEN("fast_round_up<int>(1.499999999999999) is 1") {
+        REQUIRE(fast_round_up<int>(1.499999999999999) == 1);
+    }
+    THEN("fast_round_up<int>(0.5) is 1") {
+        REQUIRE(fast_round_up<int>(0.5) == 1);
+    }
+    THEN("fast_round_up<int>(0.49999999999999994) is 0") {
+        REQUIRE(fast_round_up<int>(0.49999999999999994) == 0);
+    }
+    THEN("fast_round_up<int>(-0.5) is 0") {
+        REQUIRE(fast_round_up<int>(-0.5) == 0);
+    }
+    THEN("fast_round_up<int>(-0.51) is -1") {
+        REQUIRE(fast_round_up<int>(-0.51) == -1);
+    }
+    THEN("fast_round_up<int>(-0.51) is -1") {
+        REQUIRE(fast_round_up<int>(-0.51) == -1);
+    }
+    THEN("fast_round_up<int>(-1.5) is -1") {
+        REQUIRE(fast_round_up<int>(-1.5) == -1);
+    }
+    THEN("fast_round_up<int>(-1.51) is -2") {
+        REQUIRE(fast_round_up<int>(-1.51) == -2);
+    }
+}