Fixed transformations when deleting second-to-last sub-volume of an object

src/libslic3r/Model.cpp

@@ -661,6 +661,23 @@ void ModelObject::delete_volume(size_t idx)
     ModelVolumePtrs::iterator i = this->volumes.begin() + idx;
     delete *i;
     this->volumes.erase(i);
+
+    if (this->volumes.size() == 1)
+    {
+        // only one volume left
+        // center it and update the instances accordingly
+        // rationale: the volume may be shifted with respect to the object center and this may lead to wrong rotation and scaling 
+        // when modifying the instance matrix of the derived GLVolume
+        ModelVolume* v = this->volumes.front();
+        v->center_geometry();
+        const Vec3d& vol_offset = v->get_offset();
+        for (ModelInstance* inst : this->instances)
+        {
+            inst->set_offset(inst->get_offset() + inst->get_matrix(true) * vol_offset);
+        }
+        v->set_offset(Vec3d::Zero());
+    }
+
     this->invalidate_bounding_box();
 }
 

src/slic3r/GUI/GLCanvas3D.cpp

@@ -1924,9 +1924,17 @@ void GLCanvas3D::Selection::_update_type()
                 unsigned int volumes_count = (unsigned int)model_object->volumes.size();
                 unsigned int instances_count = (unsigned int)model_object->instances.size();
                 if (volumes_count * instances_count == 1)
+                {
                     m_type = SingleFullObject;
+                    // ensures the correct mode is selected
+                    m_mode = Instance;
+                }
                 else if (volumes_count == 1) // instances_count > 1
+                {
                     m_type = SingleFullInstance;
+                    // ensures the correct mode is selected
+                    m_mode = Instance;
+                }
                 else
                 {
                     m_type = SingleVolume;
@@ -1950,11 +1958,19 @@ void GLCanvas3D::Selection::_update_type()
                 unsigned int instances_count = (unsigned int)model_object->instances.size();
                 unsigned int selected_instances_count = (unsigned int)m_cache.content.begin()->second.size();
                 if (volumes_count * instances_count == (unsigned int)m_list.size())
+                {
                     m_type = SingleFullObject;
+                    // ensures the correct mode is selected
+                    m_mode = Instance;
+                }
                 else if (selected_instances_count == 1)
                 {
                     if (volumes_count == (unsigned int)m_list.size())
+                    {
                         m_type = SingleFullInstance;
+                        // ensures the correct mode is selected
+                        m_mode = Instance;
+                    }
                     else
                     {
                         unsigned int modifiers_count = 0;
@@ -1977,7 +1993,11 @@ void GLCanvas3D::Selection::_update_type()
                     }
                 }
                 else if ((selected_instances_count > 1) && (selected_instances_count * volumes_count == (unsigned int)m_list.size()))
+                {
                     m_type = MultipleFullInstance;
+                    // ensures the correct mode is selected
+                    m_mode = Instance;
+                }
             }
             else
             {
@@ -1990,7 +2010,11 @@ void GLCanvas3D::Selection::_update_type()
                         sels_cntr += volumes_count * instances_count;
                 }
                 if (sels_cntr == (unsigned int)m_list.size())
+                {
                     m_type = MultipleFullObject;
+                    // ensures the correct mode is selected
+                    m_mode = Instance;
+                }
             }
         }
     }
@@ -2002,66 +2026,84 @@ void GLCanvas3D::Selection::_update_type()
         v->disabled = requires_disable ? (v->object_idx() != object_idx) || (v->instance_idx() != instance_idx) : false;
     }
 
+    std::cout << "Selection: ";
+    std::cout << "mode: ";
+    switch (m_mode)
+    {
+    case Volume:
+    {
+        std::cout << "Volume";
+        break;
+    }
+    case Instance:
+    {
+        std::cout << "Instance";
+        break;
+    }
+    }
+
+    std::cout << " - type: ";
+
     switch (m_type)
     {
     case Invalid:
     {
-        std::cout << "selection type: Invalid" << std::endl;
+        std::cout << "Invalid" << std::endl;
         break;
     }
     case Empty:
     {
-        std::cout << "selection type: Empty" << std::endl;
+        std::cout << "Empty" << std::endl;
         break;
     }
     case WipeTower:
     {
-        std::cout << "selection type: WipeTower" << std::endl;
+        std::cout << "WipeTower" << std::endl;
         break;
     }
     case SingleModifier:
     {
-        std::cout << "selection type: SingleModifier" << std::endl;
+        std::cout << "SingleModifier" << std::endl;
         break;
     }
     case MultipleModifier:
     {
-        std::cout << "selection type: MultipleModifier" << std::endl;
+        std::cout << "MultipleModifier" << std::endl;
         break;
     }
     case SingleVolume:
     {
-        std::cout << "selection type: SingleVolume" << std::endl;
+        std::cout << "SingleVolume" << std::endl;
         break;
     }
     case MultipleVolume:
     {
-        std::cout << "selection type: MultipleVolume" << std::endl;
+        std::cout << "MultipleVolume" << std::endl;
         break;
     }
     case SingleFullObject:
     {
-        std::cout << "selection type: SingleFullObject" << std::endl;
+        std::cout << "SingleFullObject" << std::endl;
         break;
     }
     case MultipleFullObject:
     {
-        std::cout << "selection type: MultipleFullObject" << std::endl;
+        std::cout << "MultipleFullObject" << std::endl;
         break;
     }
     case SingleFullInstance:
     {
-        std::cout << "selection type: SingleFullInstance" << std::endl;
+        std::cout << "SingleFullInstance" << std::endl;
         break;
     }
     case MultipleFullInstance:
     {
-        std::cout << "selection type: MultipleFullInstance" << std::endl;
+        std::cout << "MultipleFullInstance" << std::endl;
         break;
     }
     case Mixed:
     {
-        std::cout << "selection type: Mixed" << std::endl;
+        std::cout << "Mixed" << std::endl;
         break;
     }
     }
@@ -3942,7 +3984,11 @@ void GLCanvas3D::reload_scene(bool refresh_immediately, bool force_full_scene_re
 					int extruder_id = mvs->model_volume->extruder_id();
 					if (extruder_id != -1)
 						volume->extruder_id = extruder_id;
-				}
+
+                    // updates volumes transformations
+                    volume->set_instance_transformation(mvs->model_volume->get_object()->instances[volume->instance_idx()]->get_transformation());
+                    volume->set_volume_transformation(mvs->model_volume->get_transformation());
+                }
             }
         }
     }