FIX:"split to parts" should consider scale_det

jira: STUDIO-8789
Change-Id: Id1b224f9e5dc2666fc4364fccde0cd79eb164f05

src/libslic3r/Model.cpp

@@ -3241,10 +3241,10 @@ std::string ModelVolume::type_to_string(const ModelVolumeType t)
 // Split this volume, append the result to the object owning this volume.
 // Return the number of volumes created from this one.
 // This is useful to assign different materials to different volumes of an object.
-size_t ModelVolume::split(unsigned int max_extruders)
+size_t ModelVolume::split(unsigned int max_extruders, float scale_det)
 {
     std::vector<std::unordered_map<int, int>> ships;
-    std::vector<TriangleMesh>  meshes = this->mesh().split_and_save_relationship(ships);
+    std::vector<TriangleMesh>  meshes = this->mesh().split_and_save_relationship(ships, scale_det);
     if (meshes.size() <= 1)
         return 1;
     if (meshes.size() != ships.size())

src/libslic3r/Model.hpp

@@ -959,7 +959,7 @@ public:
     // Split this volume, append the result to the object owning this volume.
     // Return the number of volumes created from this one.
     // This is useful to assign different materials to different volumes of an object.
-    size_t              split(unsigned int max_extruders);
+    size_t              split(unsigned int max_extruders, float scale_det = 1.f);
     void                translate(double x, double y, double z) { translate(Vec3d(x, y, z)); }
     void                translate(const Vec3d& displacement);
     void                scale(const Vec3d& scaling_factors);

src/libslic3r/TriangleMesh.cpp

@@ -386,8 +386,8 @@ bool TriangleMesh::is_splittable() const
 {
     return its_is_splittable(this->its);
 }
-
+const float  MIN_MESH_VOLUME = 1e-2f;
-std::vector<TriangleMesh> TriangleMesh::split() const
+std::vector<TriangleMesh> TriangleMesh::split(float scale_det) const
 {
     std::vector<indexed_triangle_set> itss = its_split(this->its);
     std::vector<TriangleMesh> out;
@@ -395,7 +395,7 @@ std::vector<TriangleMesh> TriangleMesh::split() const
     for (indexed_triangle_set &m : itss) {
         // The TriangleMesh constructor shall fill in the mesh statistics including volume.
         TriangleMesh temp_triangle_mesh(std::move(m));
-        if (abs(temp_triangle_mesh.volume()< 0.01)) {//0.01mm^3
+        if (abs(temp_triangle_mesh.volume() * scale_det) < MIN_MESH_VOLUME) {
             continue;
         }
         if (temp_triangle_mesh.volume() < 0) {// Some source mesh parts may be incorrectly oriented. Correct them.
@@ -406,7 +406,8 @@ std::vector<TriangleMesh> TriangleMesh::split() const
     return out;
 }
 
-std::vector<TriangleMesh> TriangleMesh::split_and_save_relationship(std::vector<std::unordered_map<int, int>> &result) const {
+std::vector<TriangleMesh> TriangleMesh::split_and_save_relationship(std::vector<std::unordered_map<int, int>> &result, float scale_det) const
+{
     auto   itss_and_ships = its_split_and_save_relationship<>(this->its);
     std::vector<TriangleMesh>         out;
     out.reserve(itss_and_ships.itses.size());
@@ -415,7 +416,7 @@ std::vector<TriangleMesh> TriangleMesh::split_and_save_relationship(std::vector<
     for (indexed_triangle_set &m : itss_and_ships.itses) {
         // The TriangleMesh constructor shall fill in the mesh statistics including volume.
         TriangleMesh temp_triangle_mesh(std::move(m));
-        if (abs(temp_triangle_mesh.volume() < 0.01)) { // 0.01mm^3
+        if (abs(temp_triangle_mesh.volume() * scale_det) < MIN_MESH_VOLUME) {
             index++;
             continue;
         }

src/libslic3r/TriangleMesh.hpp

@@ -118,8 +118,8 @@ public:
     void flip_triangles();
     void align_to_origin();
     void rotate(double angle, Point* center);
-    std::vector<TriangleMesh> split() const;
+    std::vector<TriangleMesh> split(float scale_det = 1.f) const;
-    std::vector<TriangleMesh> split_and_save_relationship(std::vector<std::unordered_map<int, int>> &result) const;
+    std::vector<TriangleMesh> split_and_save_relationship(std::vector<std::unordered_map<int, int>> &result, float scale_det = 1.f) const;
     void merge(const TriangleMesh &mesh);
     ExPolygons horizontal_projection() const;
     // 2D convex hull of a 3D mesh projected into the Z=0 plane.

src/slic3r/GUI/GUI_ObjectList.cpp

@@ -2695,12 +2695,13 @@ void ObjectList::split()
     }
 
     take_snapshot("Split to parts");
-
-    volume->split(filament_cnt);
-
     wxBusyCursor wait;
+    auto      model_object = (*m_objects)[obj_idx];
+    auto world_tran = model_object->instances[0]->get_transformation().get_matrix() * volume->get_matrix();
+    float scale_det = std::fabs(world_tran.matrix().block(0, 0, 3, 3).determinant());
+    volume->split(filament_cnt, scale_det);
+
 
-    auto model_object = (*m_objects)[obj_idx];
 
     auto parent = m_objects_model->GetObject(item);
     if (parent)