Upgrade support tree route search functions, add tests

src/libslic3r/BranchingTree/BranchingTree.hpp

@@ -20,6 +20,9 @@ class Properties
     ExPolygons m_bed_shape;
 
 public:
+
+    constexpr bool group_pillars() const noexcept { return false; }
+
     // Maximum slope for bridges of the tree
     Properties &max_slope(double val) noexcept
     {

src/libslic3r/CMakeLists.txt

@@ -356,6 +356,8 @@ set(SLIC3R_SOURCES
     BranchingTree/BranchingTree.hpp
     BranchingTree/PointCloud.cpp
     BranchingTree/PointCloud.hpp
+    OrganicTree/OrganicTree.hpp
+    OrganicTree/OrganicTreeImpl.hpp
 
     Arachne/BeadingStrategy/BeadingStrategy.hpp
     Arachne/BeadingStrategy/BeadingStrategy.cpp

src/libslic3r/Optimize/BruteforceOptimizer.hpp

@@ -13,7 +13,9 @@ template<size_t N>
 long num_iter(const std::array<size_t, N> &idx, size_t gridsz)
 {
     long ret = 0;
-    for (size_t i = 0; i < N; ++i) ret += idx[i] * std::pow(gridsz, i);
+    for (size_t i = 0; i < N; ++i)
+        ret += idx[i] * std::pow(gridsz, i);
+
     return ret;
 }
 

src/libslic3r/Optimize/NLoptOptimizer.hpp

@@ -158,7 +158,7 @@ public:
         return optimize(nl, std::forward<Func>(func), initvals);
     }
 
-    explicit NLoptOpt(StopCriteria stopcr = {}) : m_stopcr(stopcr) {}
+    explicit NLoptOpt(const StopCriteria &stopcr = {}) : m_stopcr(stopcr) {}
 
     void set_criteria(const StopCriteria &cr) { m_stopcr = cr; }
     const StopCriteria &get_criteria() const noexcept { return m_stopcr; }
@@ -226,7 +226,7 @@ using AlgNLoptGenetic = detail::NLoptAlgComb<NLOPT_GN_ESCH>;
 using AlgNLoptSubplex = detail::NLoptAlg<NLOPT_LN_SBPLX>;
 using AlgNLoptSimplex = detail::NLoptAlg<NLOPT_LN_NELDERMEAD>;
 using AlgNLoptDIRECT  = detail::NLoptAlg<NLOPT_GN_DIRECT>;
-using AlgNLoptMLSL    = detail::NLoptAlg<NLOPT_GN_MLSL>;
+using AlgNLoptMLSL    = detail::NLoptAlgComb<NLOPT_GN_MLSL, NLOPT_LN_SBPLX>;
 
 }} // namespace Slic3r::opt
 

src/libslic3r/OrganicTree/OrganicTree.hpp

@@ -0,0 +1,95 @@
+#ifndef ORGANICTREE_HPP
+#define ORGANICTREE_HPP
+
+#include <type_traits>
+#include <utility>
+#include <optional>
+
+namespace Slic3r { namespace organictree {
+
+enum class NodeType { Bed, Mesh, Junction };
+
+template <class T> struct DomainTraits_ {
+    using Node = typename T::Node;
+
+    static void push(const T &dom, const Node &n)
+    {
+        dom.push_junction(n);
+    }
+
+    static Node pop(T &dom) { return dom.pop(); }
+
+    static bool empty(const T &dom) { return dom.empty(); }
+
+    static std::optional<std::pair<Node, NodeType>>
+    closest(const T &dom, const Node &n)
+    {
+        return dom.closest(n);
+    }
+
+    static Node merge_node(const T &dom, const Node &a, const Node &b)
+    {
+        return dom.merge_node(a, b);
+    }
+
+    static void bridge(T &dom, const Node &from, const Node &to)
+    {
+        dom.bridge(from, to);
+    }
+
+    static void anchor(T &dom, const Node &from, const Node &to)
+    {
+        dom.anchor(from, to);
+    }
+
+    static void pillar(T &dom, const Node &from, const Node &to)
+    {
+        dom.pillar(from, to);
+    }
+
+    static void merge (T &dom, const Node &n1, const Node &n2, const Node &mrg)
+    {
+        dom.merge(n1, n2, mrg);
+    }
+
+    static void report_fail(T &dom, const Node &n) { dom.report_fail(n); }
+};
+
+template<class Domain>
+void build_tree(Domain &&D)
+{
+    using Dom = DomainTraits_<std::remove_cv_t<std::remove_reference_t<Domain>>>;
+    using Node = typename Dom::Node;
+
+    while (! Dom::empty(D)) {
+        Node n = Dom::pop(D);
+
+        std::optional<std::pair<Node, NodeType>> C = Dom::closest(D, n);
+
+        if (!C) {
+            Dom::report_fail(D, n);
+        } else switch (C->second) {
+            case NodeType::Bed:
+                Dom::pillar(D, n, C->first);
+                break;
+            case NodeType::Mesh:
+                Dom::anchor(D, n, C->first);
+                break;
+            case NodeType::Junction: {
+                Node M = Dom::merge_node(D, n, C->first);
+
+                if (M == C->first) {
+                    Dom::bridge(D, n, C->first);
+                } else {
+                    Dom::push(D, M);
+                    Dom::merge(D, n, M, C->first);
+                }
+                break;
+            }
+        }
+    }
+}
+
+}} // namespace Slic3r::organictree
+
+#endif // ORGANICTREE_HPP

src/libslic3r/OrganicTree/OrganicTreeImpl.hpp

@@ -0,0 +1,11 @@
+#ifndef ORGANICTREEIMPL_HPP
+#define ORGANICTREEIMPL_HPP
+
+namespace Slic3r { namespace organictree {
+
+
+
+
+}}
+
+#endif // ORGANICTREEIMPL_HPP

src/libslic3r/SLA/BranchingTreeSLA.cpp

@@ -253,13 +253,11 @@ bool BranchingTreeBuilder::add_ground_bridge(const branchingtree::Node &from,
 //        if (!result) {
             auto conn = optimize_ground_connection(
                                            ex_tbb,
-                                           m_builder,
                                            m_sm,
                                            j,
                                            get_radius(to));
 
             if (conn) {
-//                build_ground_connection(m_builder, m_sm, conn);
 //                Junction connlast = conn.path.back();
 //                branchingtree::Node n{connlast.pos.cast<float>(), float(connlast.r)};
 //                n.left = from.id;
@@ -321,6 +319,17 @@ bool BranchingTreeBuilder::add_mesh_bridge(const branchingtree::Node &from,
     return bool(anchor);
 }
 
+inline void build_pillars(SupportTreeBuilder &builder,
+                          BranchingTreeBuilder &vbuilder,
+                          const SupportableMesh &sm)
+{
+    for (size_t pill_id = 0; pill_id < vbuilder.pillars().size(); ++pill_id) {
+        auto * conn = vbuilder.ground_conn(pill_id);
+        if (conn)
+            build_ground_connection(builder, sm, *conn);
+    }
+}
+
 void create_branching_tree(SupportTreeBuilder &builder, const SupportableMesh &sm)
 {
     auto coordfn = [&sm](size_t id, size_t dim) { return sm.pts[id].pos(dim); };
@@ -373,6 +382,8 @@ void create_branching_tree(SupportTreeBuilder &builder, const SupportableMesh &s
     BranchingTreeBuilder vbuilder{builder, sm, nodes};
     branchingtree::build_tree(nodes, vbuilder);
 
+    if constexpr (props.group_pillars()) {
+
         std::vector<branchingtree::Node> bedleafs;
         for (auto n : vbuilder.pillars()) {
             n.left =  branchingtree::Node::ID_NONE;
@@ -380,27 +391,13 @@ void create_branching_tree(SupportTreeBuilder &builder, const SupportableMesh &s
             bedleafs.emplace_back(n);
         }
 
-    props.max_branch_length(50.f);
-    auto gndsm = sm;
         branchingtree::PointCloud gndnodes{{}, nodes.get_bedpoints(), bedleafs, props};
         BranchingTreeBuilder gndbuilder{builder, sm, gndnodes};
         branchingtree::build_tree(gndnodes, gndbuilder);
 
-    // All leafs of gndbuilder are nodes that already proved to be routable
+        build_pillars(builder, gndbuilder, sm);
-    // to the ground. gndbuilder should not encounter any unroutable nodes
+    } else {
-//    assert(gndbuilder.unroutable_pinheads().empty());
+        build_pillars(builder, vbuilder, sm);
-
-
-//    for (size_t pill_id = 0; pill_id < vbuilder.pillars().size(); ++pill_id) {
-//        auto * conn = vbuilder.ground_conn(pill_id);
-//        if (conn)
-//            build_ground_connection(builder, sm, *conn);
-//    }
-
-    for (size_t pill_id = 0; pill_id < gndbuilder.pillars().size(); ++pill_id) {
-        auto * conn = gndbuilder.ground_conn(pill_id);
-        if (conn)
-            build_ground_connection(builder, sm, *conn);
     }
 
     for (size_t id : vbuilder.unroutable_pinheads())

src/libslic3r/SLA/SupportTree.hpp

@@ -96,8 +96,8 @@ struct SupportTreeConfig
 
     static const double constexpr max_solo_pillar_height_mm = 15.0;
     static const double constexpr max_dual_pillar_height_mm = 35.0;
-    static const double constexpr optimizer_rel_score_diff = 1e-16;
+    static const double constexpr optimizer_rel_score_diff = 1e-10;
-    static const unsigned constexpr optimizer_max_iterations = 20000;
+    static const unsigned constexpr optimizer_max_iterations = 2000;
     static const unsigned constexpr pillar_cascade_neighbors = 3;
     
 };

src/libslic3r/SLA/SupportTreeMesher.cpp

@@ -165,7 +165,8 @@ indexed_triangle_set halfcone(double       baseheight,
 {
     assert(steps > 0);
 
-    if (baseheight <= 0 || steps <= 0) return {};
+    if (baseheight <= 0 || steps <= 0 || (r_bottom <= 0. && r_top <= 0.))
+        return {};
 
     indexed_triangle_set base;
 

src/libslic3r/SLA/SupportTreeUtils.hpp

@@ -6,6 +6,7 @@
 
 #include <libslic3r/Execution/Execution.hpp>
 #include <libslic3r/Optimize/NLoptOptimizer.hpp>
+#include <libslic3r/Optimize/BruteforceOptimizer.hpp>
 #include <libslic3r/MeshNormals.hpp>
 #include <libslic3r/Geometry.hpp>
 #include <libslic3r/SLA/SupportTreeBuilder.hpp>
@@ -644,10 +645,9 @@ struct GroundConnection {
     static constexpr size_t MaxExpectedJunctions = 3;
 
     boost::container::small_vector<Junction, MaxExpectedJunctions> path;
-    double end_radius;
     std::optional<Pedestal> pillar_base;
 
-    operator bool() const { return !path.empty(); }
+    operator bool() const { return pillar_base.has_value() && !path.empty(); }
 };
 
 template<class Ex>
@@ -659,6 +659,8 @@ GroundConnection find_pillar_route(Ex policy,
 {
     GroundConnection ret;
 
+    ret.path.emplace_back(source);
+
     Vec3d  jp           = source.pos, endp = jp, dir = sourcedir;
     bool   can_add_base = false/*, non_head = false*/;
 
@@ -666,6 +668,7 @@ GroundConnection find_pillar_route(Ex policy,
     double jp_gnd = 0.; // The lowest Z where a junction center can be
     double gap_dist = 0.; // The gap distance between the model and the pad
     double radius = source.r;
+    double sd = sm.cfg.safety_distance_mm;
 
     double r2 = radius + (end_radius - radius) / (jp.z() - ground_level(sm));
 
@@ -692,7 +695,6 @@ GroundConnection find_pillar_route(Ex policy,
                                  sm.cfg.head_back_radius_mm);
 
         if (diffbr && diffbr->endp.z() > jp_gnd) {
-            ret.path.emplace_back(source);
             endp = diffbr->endp;
             radius = diffbr->end_r;
             ret.path.emplace_back(endp, radius);
@@ -709,7 +711,6 @@ GroundConnection find_pillar_route(Ex policy,
         auto [polar, azimuth] = dir_to_spheric(dir);
         polar = PI - sm.cfg.bridge_slope;
         Vec3d d = spheric_to_dir(polar, azimuth).normalized();
-        auto sd = sm.cfg.safety_distance_mm; //radius * sm.cfg.safety_distance_mm / sm.cfg.head_back_radius_mm;
         double t = beam_mesh_hit(policy, sm.emesh, Beam{endp, d, radius, r2}, sd).distance();
         double tmax = std::min(sm.cfg.max_bridge_length_mm, t);
         t = 0.;
@@ -759,15 +760,19 @@ GroundConnection find_pillar_route(Ex policy,
     }
 
     Vec3d gp = to_floor(endp);
+    auto hit = beam_mesh_hit(policy, sm.emesh,
+                             Beam{{endp, radius}, {gp, end_radius}}, sd);
 
-    ret.end_radius = end_radius;
+    if (std::isinf(hit.distance())) {
+        double base_radius = can_add_base ?
+                    std::max(sm.cfg.base_radius_mm, end_radius) : end_radius;
 
-    if (can_add_base) {
+        Vec3d gp = to_floor(endp);
         ret.pillar_base =
-            Pedestal{gp, sm.cfg.base_height_mm, sm.cfg.base_radius_mm, end_radius};
+            Pedestal{gp, sm.cfg.base_height_mm, base_radius, end_radius};
     }
 
-    return ret; //{true, pillar_id};
+    return ret;
 }
 
 inline long build_ground_connection(SupportTreeBuilder &builder,
@@ -798,9 +803,8 @@ inline long build_ground_connection(SupportTreeBuilder &builder,
 //        long head_id = std::abs(conn.path.back().id);
 //        ret = builder.add_pillar(head_id, h);
 //    } else
-        ret = builder.add_pillar(gp, h, conn.path.back().r, conn.end_radius);
+        ret = builder.add_pillar(gp, h, conn.path.back().r, conn.pillar_base->r_top);
 
-    if (conn.pillar_base)
     builder.add_pillar_base(ret, conn.pillar_base->height, conn.pillar_base->r_bottom);
 
     return ret;
@@ -809,7 +813,6 @@ inline long build_ground_connection(SupportTreeBuilder &builder,
 template<class Ex>
 GroundConnection find_ground_connection(
     Ex                     policy,
-    SupportTreeBuilder    &builder,
     const SupportableMesh &sm,
     const Junction        &j,
     const Vec3d           &dir,
@@ -817,39 +820,36 @@ GroundConnection find_ground_connection(
 {
     auto   hjp = j.pos;
     double r   = j.r;
-    auto   sd  = sm.cfg.safety_distance_mm; //r * sm.cfg.safety_distance_mm / sm.cfg.head_back_radius_mm;
+    auto   sd  = sm.cfg.safety_distance_mm;
     double r2  = j.r + (end_r - j.r) / (j.pos.z() - ground_level(sm));
 
-    double t = beam_mesh_hit(policy, sm.emesh, Beam{hjp, dir, r, r2}, sd)
+    double t = beam_mesh_hit(policy, sm.emesh, Beam{hjp, dir, r, r2}, sd).distance();
-                   .distance();
+    t = std::min(t, sm.cfg.max_bridge_length_mm);
-    double d = 0, tdown = 0;
+    double d = 0.;
-    t = std::min(t,
+
-                 sm.cfg.max_bridge_length_mm * r / sm.cfg.head_back_radius_mm);
+    GroundConnection gnd_route;
+
+    while (!gnd_route && d < t) {
+        Vec3d  endp = hjp + d * dir;
+        double bridge_ratio = d / (d + (endp.z() - sm.emesh.ground_level()));
+        double pill_r = r + bridge_ratio * (end_r - r);
+        gnd_route = find_pillar_route(policy, sm, {endp, pill_r}, dir, end_r);
 
-    while (
-        d < t &&
-        !std::isinf(tdown = beam_mesh_hit(policy, sm.emesh,
-                                          Beam{hjp + d * dir, DOWN, r, r2}, sd)
-                                .distance())) {
         d += r;
     }
 
     GroundConnection ret;
-    ret.end_radius = end_r;
 
-    if (std::isinf(tdown)) {
+    if (d > 0.)
-        ret.path.emplace_back(j);
-        Vec3d  endp         = hjp + d * dir;
-        double bridge_ratio = d / (d + (endp.z() - sm.emesh.ground_level()));
-        double pill_r = r + bridge_ratio * (end_r - r);
-
-        auto route = find_pillar_route(policy, sm, {endp, pill_r}, dir, end_r);
-        for (auto &j : route.path)
         ret.path.emplace_back(j);
 
-        ret.pillar_base = route.pillar_base;
+    for (auto &p : gnd_route.path)
-        ret.end_radius  = end_r;
+        ret.path.emplace_back(p);
-    }
+
+    // This will ultimately determine if the route is valid or not
+    // but the path junctions will be provided anyways, so invalid paths
+    // can be debugged
+    ret.pillar_base = gnd_route.pillar_base;
 
     return ret;
 }
@@ -857,7 +857,6 @@ GroundConnection find_ground_connection(
 template<class Ex>
 GroundConnection optimize_ground_connection(
     Ex                     policy,
-    SupportTreeBuilder    &builder,
     const SupportableMesh &sm,
     const Junction        &j,
     double                 end_radius,
@@ -865,8 +864,8 @@ GroundConnection optimize_ground_connection(
 {
     double downdst = j.pos.z() - ground_level(sm);
 
-    auto res = find_ground_connection(policy, builder, sm, j, init_dir, end_radius);
+    auto res = find_ground_connection(policy, sm, j, init_dir, end_radius);
-    if (!res)
+    if (res)
         return res;
 
     // Optimize bridge direction:
@@ -874,7 +873,7 @@ GroundConnection optimize_ground_connection(
     // direction out of the cavity.
     auto [polar, azimuth] = dir_to_spheric(init_dir);
 
-    Optimizer<AlgNLoptGenetic> solver(get_criteria(sm.cfg).stop_score(1e6));
+    Optimizer<opt::AlgNLoptMLSL> solver(get_criteria(sm.cfg).stop_score(1e6));
     solver.seed(0); // we want deterministic behavior
 
     auto   sd  = /*j.r **/ sm.cfg.safety_distance_mm /*/ sm.cfg.head_back_radius_mm*/;
@@ -891,7 +890,7 @@ GroundConnection optimize_ground_connection(
 
     Vec3d bridgedir = spheric_to_dir(oresult.optimum).normalized();
 
-    return find_ground_connection(policy, builder, sm, j, bridgedir, end_radius);
+    return find_ground_connection(policy, sm, j, bridgedir, end_radius);
 }
 
 template<class Ex>
@@ -904,7 +903,7 @@ std::pair<bool, long> connect_to_ground(Ex                     policy,
 {
     std::pair<bool, long> ret = {false, SupportTreeNode::ID_UNSET};
 
-    auto conn = find_ground_connection(policy, builder, sm, j, dir, end_r);
+    auto conn = find_ground_connection(policy, sm, j, dir, end_r);
     ret.first = bool(conn);
     ret.second = build_ground_connection(builder, sm, conn);
 
@@ -921,8 +920,7 @@ std::pair<bool, long> search_ground_route(Ex                     policy,
 {
     std::pair<bool, long> ret = {false, SupportTreeNode::ID_UNSET};
 
-    auto conn = optimize_ground_connection(policy, builder, sm, j,
+    auto conn = optimize_ground_connection(policy, sm, j, end_r, init_dir);
-                                                       end_r, init_dir);
 
     ret.first = bool(conn);
     ret.second = build_ground_connection(builder, sm, conn);

src/slic3r/GUI/Gizmos/GLGizmoSlaSupports.cpp

@@ -12,6 +12,8 @@
 #include <wx/settings.h>
 #include <wx/stattext.h>
 
+#include <boost/log/trivial.hpp>
+
 #include "slic3r/GUI/GUI_App.hpp"
 #include "slic3r/GUI/GUI.hpp"
 #include "slic3r/GUI/GUI_ObjectSettings.hpp"
@@ -1019,6 +1021,8 @@ void GLGizmoSlaSupports::select_point(int i)
             m_new_point_head_diameter = m_editing_cache[0].support_point.head_front_radius * 2.f;
     }
     else {
+        if (!m_editing_cache[i].selected)
+            BOOST_LOG_TRIVIAL(debug) << "Support point selected [" << i << "]: " << m_editing_cache[i].support_point.pos.transpose() << " \tnormal: " << m_editing_cache[i].normal.transpose();
         m_editing_cache[i].selected = true;
         m_selection_empty = false;
         m_new_point_head_diameter = m_editing_cache[i].support_point.head_front_radius * 2.f;

tests/data/U_overhang.obj

@@ -0,0 +1,76 @@
+####
+#
+# OBJ File Generated by Meshlab
+#
+####
+# Object U_overhang.obj
+#
+# Vertices: 16
+# Faces: 28
+#
+####
+vn 1.570797 1.570796 1.570796
+v 10.000000 10.000000 11.000000
+vn 4.712389 1.570796 -1.570796
+v 10.000000 1.000000 10.000000
+vn 1.570796 1.570796 -1.570796
+v 10.000000 10.000000 10.000000
+vn 1.570796 -1.570796 1.570796
+v 10.000000 0.000000 11.000000
+vn 4.712389 1.570796 1.570796
+v 10.000000 1.000000 1.000000
+vn 1.570797 1.570796 -1.570796
+v 10.000000 10.000000 0.000000
+vn 1.570796 1.570796 1.570796
+v 10.000000 10.000000 1.000000
+vn 1.570796 -1.570796 -1.570796
+v 10.000000 0.000000 0.000000
+vn -1.570796 1.570796 1.570796
+v 0.000000 10.000000 1.000000
+vn -4.712389 1.570796 1.570796
+v 0.000000 1.000000 1.000000
+vn -1.570796 -1.570796 -1.570796
+v 0.000000 0.000000 0.000000
+vn -1.570797 1.570796 -1.570796
+v 0.000000 10.000000 0.000000
+vn -4.712389 1.570796 -1.570796
+v 0.000000 1.000000 10.000000
+vn -1.570797 1.570796 1.570796
+v 0.000000 10.000000 11.000000
+vn -1.570796 1.570796 -1.570796
+v 0.000000 10.000000 10.000000
+vn -1.570796 -1.570796 1.570796
+v 0.000000 0.000000 11.000000
+# 16 vertices, 0 vertices normals
+
+f 1//1 2//2 3//3
+f 2//2 4//4 5//5
+f 4//4 2//2 1//1
+f 5//5 6//6 7//7
+f 5//5 8//8 6//6
+f 8//8 5//5 4//4
+f 9//9 5//5 7//7
+f 5//5 9//9 10//10
+f 11//11 6//6 8//8
+f 6//6 11//11 12//12
+f 12//12 10//10 9//9
+f 10//10 11//11 13//13
+f 11//11 10//10 12//12
+f 13//13 14//14 15//15
+f 13//13 16//16 14//14
+f 16//16 13//13 11//11
+f 6//6 9//9 7//7
+f 9//9 6//6 12//12
+f 11//11 4//4 16//16
+f 4//4 11//11 8//8
+f 13//13 3//3 2//2
+f 3//3 13//13 15//15
+f 5//5 13//13 2//2
+f 13//13 5//5 10//10
+f 14//14 4//4 1//1
+f 4//4 14//14 16//16
+f 3//3 14//14 1//1
+f 14//14 3//3 15//15
+# 28 faces, 0 coords texture
+
+# End of File

tests/sla_print/CMakeLists.txt

@@ -4,6 +4,7 @@ add_executable(${_TEST_NAME}_tests ${_TEST_NAME}_tests_main.cpp
     sla_test_utils.hpp sla_test_utils.cpp
     sla_supptgen_tests.cpp
     sla_raycast_tests.cpp
+    sla_supptreeutils_tests.cpp
     sla_archive_readwrite_tests.cpp)
 
 # mold linker for successful linking needs also to link TBB library and link it before libslic3r.

tests/sla_print/sla_supptreeutils_tests.cpp

@@ -0,0 +1,119 @@
+#include <catch2/catch.hpp>
+#include <test_utils.hpp>
+
+#include "libslic3r/Execution/ExecutionSeq.hpp"
+#include "libslic3r/SLA/SupportTreeUtils.hpp"
+
+TEST_CASE("Avoid disk below junction", "[suptreeutils]")
+{
+    // In this test there will be a disk mesh with some radius, centered at
+    // (0, 0, 0) and above the disk, a junction from which the support pillar
+    // should be routed. The algorithm needs to find an avoidance route.
+
+    using namespace Slic3r;
+
+    constexpr double FromRadius = .5;
+    constexpr double EndRadius  = 1.;
+    constexpr double CylRadius  = 4.;
+    constexpr double CylHeight  = 1.;
+
+    sla::SupportTreeConfig cfg;
+
+    indexed_triangle_set disk = its_make_cylinder(CylRadius, CylHeight);
+
+    // 2.5 * CyRadius height should be enough to be able to insert a bridge
+    // with 45 degree tilt above the disk.
+    sla::Junction j{Vec3d{0., 0., 2.5 * CylRadius}, FromRadius};
+
+    sla::SupportableMesh sm{disk, sla::SupportPoints{}, cfg};
+
+    sla::GroundConnection conn =
+            sla::optimize_ground_connection(ex_seq, sm, j, EndRadius, sla::DOWN);
+
+#ifndef NDEBUG
+
+    sla::SupportTreeBuilder builder;
+
+    if (!conn)
+        builder.add_junction(j);
+
+    sla::build_ground_connection(builder, sm, conn);
+
+    its_merge(disk, builder.merged_mesh());
+
+    its_write_stl_ascii("output_disk.stl", "disk", disk);
+#endif
+
+    REQUIRE(bool(conn));
+
+    // The route should include the source and one avoidance junction.
+    REQUIRE(conn.path.size() == 2);
+
+    // The end radius end the pillar base's upper radius should match
+    REQUIRE(conn.pillar_base->r_top == Approx(EndRadius));
+
+    // Check if the avoidance junction is indeed outside of the disk barrier's
+    // edge.
+    auto p = conn.path.back().pos;
+    double pR = std::sqrt(p.x() * p.x()) + std::sqrt(p.y() * p.y());
+    REQUIRE(pR + FromRadius > CylRadius);
+}
+
+TEST_CASE("Avoid disk below junction with barrier on the side", "[suptreeutils]")
+{
+    // In this test there will be a disk mesh with some radius, centered at
+    // (0, 0, 0) and above the disk, a junction from which the support pillar
+    // should be routed. The algorithm needs to find an avoidance route.
+
+    using namespace Slic3r;
+
+    constexpr double FromRadius = .5;
+    constexpr double EndRadius  = 1.;
+    constexpr double CylRadius  = 4.;
+    constexpr double CylHeight  = 1.;
+    constexpr double JElevX     = 2.5;
+
+    sla::SupportTreeConfig cfg;
+
+    indexed_triangle_set disk = its_make_cylinder(CylRadius, CylHeight);
+    indexed_triangle_set wall = its_make_cube(1., 2 * CylRadius, JElevX * CylRadius);
+    its_translate(wall, Vec3f{float(FromRadius), -float(CylRadius), 0.f});
+    its_merge(disk, wall);
+
+    // 2.5 * CyRadius height should be enough to be able to insert a bridge
+    // with 45 degree tilt above the disk.
+    sla::Junction j{Vec3d{0., 0., JElevX * CylRadius}, FromRadius};
+
+    sla::SupportableMesh sm{disk, sla::SupportPoints{}, cfg};
+
+    sla::GroundConnection conn =
+            sla::optimize_ground_connection(ex_seq, sm, j, EndRadius, sla::DOWN);
+
+#ifndef NDEBUG
+
+    sla::SupportTreeBuilder builder;
+
+    if (!conn)
+        builder.add_junction(j);
+
+    sla::build_ground_connection(builder, sm, conn);
+
+    its_merge(disk, builder.merged_mesh());
+
+    its_write_stl_ascii("output_disk_wall.stl", "disk_wall", disk);
+#endif
+
+    REQUIRE(bool(conn));
+
+    // The route should include the source and one avoidance junction.
+    REQUIRE(conn.path.size() == 2);
+
+    // The end radius end the pillar base's upper radius should match
+    REQUIRE(conn.pillar_base->r_top == Approx(EndRadius));
+
+    // Check if the avoidance junction is indeed outside of the disk barrier's
+    // edge.
+    auto p = conn.path.back().pos;
+    double pR = std::sqrt(p.x() * p.x()) + std::sqrt(p.y() * p.y());
+    REQUIRE(pR + FromRadius > CylRadius);
+}