Reworked connection of infill lines to perimeter lines.

Added a new "infill_anchor" parameter.

src/libslic3r/Fill/Fill.cpp

@@ -37,6 +37,8 @@ struct SurfaceFillParams
     bool        	dont_connect = false;
     // Don't adjust spacing to fill the space evenly.
     bool        	dont_adjust = false;
+    // Length of the infill anchor along the perimeter line.
+    float 			anchor_length = std::numeric_limits<float>::max();
 
     // width, height of extrusion, nozzle diameter, is bridge
     // For the output, for fill generator.
@@ -67,6 +69,7 @@ struct SurfaceFillParams
 		RETURN_COMPARE_NON_EQUAL(density);
 		RETURN_COMPARE_NON_EQUAL_TYPED(unsigned, dont_connect);
 		RETURN_COMPARE_NON_EQUAL_TYPED(unsigned, dont_adjust);
+		RETURN_COMPARE_NON_EQUAL(anchor_length);
 		RETURN_COMPARE_NON_EQUAL(flow.width);
 		RETURN_COMPARE_NON_EQUAL(flow.height);
 		RETURN_COMPARE_NON_EQUAL(flow.nozzle_diameter);
@@ -85,6 +88,7 @@ struct SurfaceFillParams
 				this->density   		== rhs.density   		&&
 				this->dont_connect  	== rhs.dont_connect 	&&
 				this->dont_adjust   	== rhs.dont_adjust 		&&
+				this->anchor_length		== rhs.anchor_length    &&
 				this->flow 				== rhs.flow 			&&
 				this->extrusion_role	== rhs.extrusion_role;
 	}
@@ -115,16 +119,17 @@ std::vector<SurfaceFill> group_fills(const Layer &layer)
 	        if (surface.surface_type == stInternalVoid)
 	        	has_internal_voids = true;
 	        else {
+		        const PrintRegionConfig &region_config = layerm.region()->config();
 		        FlowRole extrusion_role = surface.is_top() ? frTopSolidInfill : (surface.is_solid() ? frSolidInfill : frInfill);
 		        bool     is_bridge 	    = layer.id() > 0 && surface.is_bridge();
 		        params.extruder 	 = layerm.region()->extruder(extrusion_role);
-		        params.pattern 		 = layerm.region()->config().fill_pattern.value;
+		        params.pattern 		 = region_config.fill_pattern.value;
-		        params.density       = float(layerm.region()->config().fill_density);
+		        params.density       = float(region_config.fill_density);
 
 		        if (surface.is_solid()) {
 		            params.density = 100.f;
 		            params.pattern = (surface.is_external() && ! is_bridge) ? 
-						(surface.is_top() ? layerm.region()->config().top_fill_pattern.value : layerm.region()->config().bottom_fill_pattern.value) :
+						(surface.is_top() ? region_config.top_fill_pattern.value : region_config.bottom_fill_pattern.value) :
 		                ipRectilinear;
 		        } else if (params.density <= 0)
 		            continue;
@@ -136,7 +141,7 @@ std::vector<SurfaceFill> group_fills(const Layer &layer)
 		                    (surface.is_top() ? erTopSolidInfill : erSolidInfill) :
 		                    erInternalInfill);
 		        params.bridge_angle = float(surface.bridge_angle);
-		        params.angle 		= float(Geometry::deg2rad(layerm.region()->config().fill_angle.value));
+		        params.angle 		= float(Geometry::deg2rad(region_config.fill_angle.value));
 		        
 		        // calculate the actual flow we'll be using for this infill
 		        params.flow = layerm.region()->flow(
@@ -165,6 +170,10 @@ std::vector<SurfaceFill> group_fills(const Layer &layer)
 		        } else
 		            params.spacing = params.flow.spacing();
 
+		        params.anchor_length = float(region_config.infill_anchor);
+		        if (region_config.infill_anchor.percent)
+		        	params.anchor_length *= 0.01 * params.spacing;
+
 		        auto it_params = set_surface_params.find(params);
 		        if (it_params == set_surface_params.end())
 		        	it_params = set_surface_params.insert(it_params, params);
@@ -369,6 +378,7 @@ void Layer::make_fills(FillAdaptive::Octree* adaptive_fill_octree, FillAdaptive:
         FillParams params;
         params.density 		 = float(0.01 * surface_fill.params.density);
         params.dont_adjust 	 = surface_fill.params.dont_adjust; // false
+        params.anchor_length = surface_fill.params.anchor_length;
 
         for (ExPolygon &expoly : surface_fill.expolygons) {
 			// Spacing is modified by the filler to indicate adjustments. Reset it for each expolygon.

src/libslic3r/Fill/FillAdaptive.cpp

@@ -639,7 +639,6 @@ static inline Intersection* get_nearest_intersection(std::vector<std::pair<Inter
 // translated in the direction of the intersection line (intersection.intersect_line).
 static Line create_offset_line(Line offset_line, const Intersection &intersection, const double scaled_offset)
 {
-    // 50% overlap of the extrusion lines to achieve strong bonding.
     offset_line.translate((perp(intersection.closest_line->vector().cast<double>().normalized()) * (intersection.left ? scaled_offset : - scaled_offset)).cast<coord_t>());
     // Extend the line by a small value to guarantee a collision with adjacent lines
     offset_line.extend(coord_t(scaled_offset * 1.16)); // / cos(PI/6)
@@ -767,8 +766,10 @@ static Polylines connect_lines_using_hooks(Polylines &&lines, const ExPolygon &b
     lines_src.reserve(lines.size());
     std::transform(lines.begin(), lines.end(), std::back_inserter(lines_src), [](const Line& l) { return Polyline{ l.a, l.b }; });
 
-    const float scaled_offset           = float(scale_(spacing) * 0.7); // 30% overlap
+    // 19% overlap, slightly lower than the allowed overlap in Fill::connect_infill()
-    const float scaled_trim_distance    = float(scale_(spacing) * 0.5 * 0.75); // 25% overlap
+    const float scaled_offset           = float(scale_(spacing) * 0.81);
+    // 25% overlap
+    const float scaled_trim_distance    = float(scale_(spacing) * 0.5 * 0.75);
 
     // Keeping the vector of closest points outside the loop, so the vector does not need to be reallocated.
     std::vector<std::pair<rtree_segment_t, size_t>> closest;
@@ -1199,9 +1200,6 @@ static Polylines connect_lines_using_hooks(Polylines &&lines, const ExPolygon &b
     return polylines_out;
 }
 
-//coord_t get_hook_length(const double spacing) { return coord_t(scale_(spacing)) * 2; }
-coord_t get_hook_length(const double spacing) { return coord_t(scale_(spacing)) * 5; }
-
 #ifndef NDEBUG
 bool has_no_collinear_lines(const Polylines &polylines)
 {
@@ -1323,7 +1321,8 @@ void Filler::_fill_surface_single(
     }
 #endif /* ADAPTIVE_CUBIC_INFILL_DEBUG_OUTPUT */
 
-    coord_t   hook_length = get_hook_length(this->spacing);
+    const auto hook_length = coord_t(std::min(scale_(this->spacing * 5), scale_(params.anchor_length)));
+
     Polylines all_polylines_with_hooks = all_polylines.size() > 1 ? connect_lines_using_hooks(std::move(all_polylines), expolygon, this->spacing, hook_length) : std::move(all_polylines);
 
 #ifdef ADAPTIVE_CUBIC_INFILL_DEBUG_OUTPUT
@@ -1336,7 +1335,7 @@ void Filler::_fill_surface_single(
     if (params.dont_connect || all_polylines_with_hooks.size() <= 1)
         append(polylines_out, std::move(all_polylines_with_hooks));
     else
-        connect_infill(chain_polylines(std::move(all_polylines_with_hooks)), expolygon, polylines_out, this->spacing, params, hook_length);
+        connect_infill(chain_polylines(std::move(all_polylines_with_hooks)), expolygon, polylines_out, this->spacing, params);
 
 #ifdef ADAPTIVE_CUBIC_INFILL_DEBUG_OUTPUT
     {

src/libslic3r/Fill/FillBase.hpp

@@ -37,6 +37,9 @@ struct FillParams
     // Fill density, fraction in <0, 1>
     float       density 		{ 0.f };
 
+    // Length of an infill anchor along the perimeter.
+    float       anchor_length   { std::numeric_limits<float>::max() };
+
     // Don't connect the fill lines around the inner perimeter.
     bool        dont_connect 	{ false };
 
@@ -124,9 +127,9 @@ protected:
     virtual std::pair<float, Point> _infill_direction(const Surface *surface) const;
 
 public:
-    static void connect_infill(Polylines &&infill_ordered, const ExPolygon &boundary, Polylines &polylines_out, const double spacing, const FillParams &params, const int hook_length = 0);
+    static void connect_infill(Polylines &&infill_ordered, const ExPolygon &boundary, Polylines &polylines_out, const double spacing, const FillParams &params);
-    static void connect_infill(Polylines &&infill_ordered, const Polygons &boundary, const BoundingBox& bbox, Polylines &polylines_out, const double spacing, const FillParams &params, const int hook_length = 0);
+    static void connect_infill(Polylines &&infill_ordered, const Polygons &boundary, const BoundingBox& bbox, Polylines &polylines_out, const double spacing, const FillParams &params);
-    static void connect_infill(Polylines &&infill_ordered, const std::vector<const Polygon*> &boundary, const BoundingBox &bbox, Polylines &polylines_out, double spacing, const FillParams &params, const int hook_length = 0);
+    static void connect_infill(Polylines &&infill_ordered, const std::vector<const Polygon*> &boundary, const BoundingBox &bbox, Polylines &polylines_out, double spacing, const FillParams &params);
 
     static coord_t  _adjust_solid_spacing(const coord_t width, const coord_t distance);
 

src/libslic3r/Fill/FillRectilinear2.cpp

@@ -2778,6 +2778,7 @@ bool FillRectilinear2::fill_surface_by_multilines(const Surface *surface, FillPa
         return true;
 
     Polylines fill_lines;
+    coord_t line_width   = coord_t(scale_(this->spacing));
     coord_t line_spacing = coord_t(scale_(this->spacing) / params.density);
     std::pair<float, Point> rotate_vector = this->_infill_direction(surface);
     for (const SweepParams &sweep : sweep_params) {
@@ -2787,6 +2788,9 @@ bool FillRectilinear2::fill_surface_by_multilines(const Surface *surface, FillPa
         double angle = rotate_vector.first + sweep.angle_base;
         ExPolygonWithOffset poly_with_offset(poly_with_offset_base, - angle);
         BoundingBox bounding_box = poly_with_offset.bounding_box_src();
+        // Don't produce infill lines, which fully overlap with the infill perimeter.
+        coord_t     x_min = bounding_box.min.x() + line_width + coord_t(SCALED_EPSILON);
+        coord_t     x_max = bounding_box.max.x() - line_width - coord_t(SCALED_EPSILON);
         // extend bounding box so that our pattern will be aligned with other layers
         // Transform the reference point to the rotated coordinate system.
         Point refpt = rotate_vector.second.rotated(- angle);
@@ -2800,7 +2804,10 @@ bool FillRectilinear2::fill_surface_by_multilines(const Surface *surface, FillPa
         const size_t n_vlines = (bounding_box.max.x() - bounding_box.min.x() + line_spacing - 1) / line_spacing;
         const double cos_a    = cos(angle);
         const double sin_a    = sin(angle);
-        for (const SegmentedIntersectionLine &vline : slice_region_by_vertical_lines(poly_with_offset, n_vlines, bounding_box.min.x(), line_spacing)) {
+        for (const SegmentedIntersectionLine &vline : slice_region_by_vertical_lines(poly_with_offset, n_vlines, bounding_box.min.x(), line_spacing))
+            if (vline.pos > x_min) {
+                if (vline.pos >= x_max)
+                    break;
                 for (auto it = vline.intersections.begin(); it != vline.intersections.end();) {
                     auto it_low  = it ++;
                     assert(it_low->type == SegmentIntersection::OUTER_LOW);
@@ -2821,11 +2828,8 @@ bool FillRectilinear2::fill_surface_by_multilines(const Surface *surface, FillPa
 
     if (params.dont_connect || fill_lines.size() <= 1)
         append(polylines_out, std::move(fill_lines));
-    else {
+    else
-//        coord_t hook_length = 0;
+        connect_infill(std::move(fill_lines), poly_with_offset_base.polygons_outer, get_extents(surface->expolygon.contour), polylines_out, this->spacing, params);
-        coord_t hook_length = coord_t(scale_(this->spacing)) * 5;
-        connect_infill(std::move(fill_lines), poly_with_offset_base.polygons_outer, get_extents(surface->expolygon.contour), polylines_out, this->spacing, params, hook_length);
-    }
 
     return true;
 }

src/libslic3r/Preset.cpp

@@ -427,7 +427,7 @@ const std::vector<std::string>& Preset::print_options()
         "infill_extruder", "solid_infill_extruder", "support_material_extruder", "support_material_interface_extruder",
         "ooze_prevention", "standby_temperature_delta", "interface_shells", "extrusion_width", "first_layer_extrusion_width",
         "perimeter_extrusion_width", "external_perimeter_extrusion_width", "infill_extrusion_width", "solid_infill_extrusion_width",
-        "top_infill_extrusion_width", "support_material_extrusion_width", "infill_overlap", "bridge_flow_ratio", "clip_multipart_objects",
+        "top_infill_extrusion_width", "support_material_extrusion_width", "infill_overlap", "infill_anchor", "bridge_flow_ratio", "clip_multipart_objects",
         "elefant_foot_compensation", "xy_size_compensation", "threads", "resolution", "wipe_tower", "wipe_tower_x", "wipe_tower_y",
         "wipe_tower_width", "wipe_tower_rotation_angle", "wipe_tower_bridging", "single_extruder_multi_material_priming",
         "wipe_tower_no_sparse_layers", "compatible_printers", "compatible_printers_condition", "inherits"

src/libslic3r/PrintConfig.cpp

@@ -1050,6 +1050,16 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionInt(1));
 
+    def = this->add("infill_anchor", coFloatOrPercent);
+    def->label = L("Length of the infill anchor");
+    def->category = L("Advanced");
+    def->tooltip = L("Connect an infill line to an internal perimeter with a short segment of an additional perimeter. "
+                     "If expressed as percentage (example: 15%) it is calculated over infill extrusion width.");
+    def->sidetext = L("mm or %");
+    def->ratio_over = "infill_extrusion_width";
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloatOrPercent(300, true));
+
     def = this->add("infill_extruder", coInt);
     def->label = L("Infill extruder");
     def->category = L("Extruders");

src/libslic3r/PrintConfig.hpp

@@ -530,6 +530,7 @@ public:
     ConfigOptionPercent             fill_density;
     ConfigOptionEnum<InfillPattern> fill_pattern;
     ConfigOptionFloat               gap_fill_speed;
+    ConfigOptionFloatOrPercent      infill_anchor;
     ConfigOptionInt                 infill_extruder;
     ConfigOptionFloatOrPercent      infill_extrusion_width;
     ConfigOptionInt                 infill_every_layers;
@@ -581,6 +582,7 @@ protected:
         OPT_PTR(fill_density);
         OPT_PTR(fill_pattern);
         OPT_PTR(gap_fill_speed);
+        OPT_PTR(infill_anchor);
         OPT_PTR(infill_extruder);
         OPT_PTR(infill_extrusion_width);
         OPT_PTR(infill_every_layers);

src/libslic3r/PrintObject.cpp

@@ -590,7 +590,7 @@ bool PrintObject::invalidate_state_by_config_options(const std::vector<t_config_
             || opt_key == "external_fill_link_max_length"
             || opt_key == "fill_angle"
             || opt_key == "fill_pattern"
-            || opt_key == "fill_link_max_length"
+            || opt_key == "infill_anchor"
             || opt_key == "top_infill_extrusion_width"
             || opt_key == "first_layer_extrusion_width") {
             steps.emplace_back(posInfill);

src/slic3r/GUI/Tab.cpp

@@ -1424,6 +1424,7 @@ void TabPrint::build()
         optgroup->append_single_option_line("fill_pattern", category_path + "fill-pattern");
         optgroup->append_single_option_line("top_fill_pattern", category_path + "top-fill-pattern");
         optgroup->append_single_option_line("bottom_fill_pattern", category_path + "bottom-fill-pattern");
+        optgroup->append_single_option_line("infill_anchor", category_path + "fill-pattern");
 
         optgroup = page->new_optgroup(L("Ironing"));
         optgroup->append_single_option_line("ironing");

xs/lib/Slic3r/XS.pm

@@ -145,7 +145,6 @@ package Slic3r::Filler;
 sub fill_surface {
     my ($self, $surface, %args) = @_;
     $self->set_density($args{density}) if defined($args{density});
-    $self->set_dont_connect($args{dont_connect}) if defined($args{dont_connect});
     $self->set_dont_adjust($args{dont_adjust}) if defined($args{dont_adjust});
     $self->set_complete($args{complete}) if defined($args{complete});
     return $self->_fill_surface($surface);

xs/xsp/Filler.xsp

@@ -34,8 +34,6 @@
 
     void set_density(float density)
         %code{% THIS->params.density = density; %};
-    void set_dont_connect(bool dont_connect)
-        %code{% THIS->params.dont_connect = dont_connect; %};
     void set_dont_adjust(bool dont_adjust)
         %code{% THIS->params.dont_adjust = dont_adjust; %};
     void set_complete(bool complete)