Follow-up 1b451cd: Fixed #11415 - Connectors disappear when slicing =…

…> only when using multiple cut planes AND excluding parts

Note: With this issue was related crash on perform a cut (SPE-1938),
because a variable with ended lifetime was used

src/libslic3r/CutUtils.cpp

@@ -464,6 +464,12 @@ const ModelObjectPtrs& Cut::perform_by_contour(std::vector<Part> parts, int dowe
 
         // Just add Upper and Lower objects to cut_object_ptrs
         post_process(upper, lower, cut_object_ptrs);
+
+        // Now merge all model parts together:
+        merge_solid_parts_inside_object(cut_object_ptrs);
+
+        // replace initial objects in model with cut object 
+        finalize(cut_object_ptrs);
     }
     else if (volumes.size() > cut_parts_cnt) {
         // Means that object is cut with connectors
@@ -490,17 +496,18 @@ const ModelObjectPtrs& Cut::perform_by_contour(std::vector<Part> parts, int dowe
         // Add Upper and Lower objects to cut_object_ptrs
         post_process(upper, lower, cut_object_ptrs);
 
-        // Add Dowel-connectors as separate objects to cut_object_ptrs
+        // Now merge all model parts together:
+        merge_solid_parts_inside_object(cut_object_ptrs);
+
+        // replace initial objects in model with cut object
+        finalize(cut_object_ptrs);
+
+        // Add Dowel-connectors as separate objects to model
         if (cut_connectors_obj.size() >= 3)
             for (size_t id = 2; id < cut_connectors_obj.size(); id++)
-                cut_object_ptrs.push_back(cut_connectors_obj[id]);
+                m_model.add_object(*cut_connectors_obj[id]);
     }
 
-    // Now merge all model parts together:
-    merge_solid_parts_inside_object(cut_object_ptrs);
-
-    finalize(cut_object_ptrs);
-
     return m_model.objects;
 }