Fix NaN when adding negative part (#3423) (#3431)

(cherry picked from commit 1ea33f0)

src/slic3r/GUI/GUI_ObjectList.cpp

@@ -2149,8 +2149,8 @@ void ObjectList::load_generic_subobject(const std::string& type_name, const Mode
     // First (any) GLVolume of the selected instance. They all share the same instance matrix.
     const GLVolume* v = selection.get_first_volume();
     // Transform the new modifier to be aligned with the print bed.
-	const BoundingBoxf3 mesh_bb = new_volume->mesh().bounding_box();
-    new_volume->set_transformation(Geometry::Transformation::volume_to_bed_transformation(v->get_instance_transformation(), mesh_bb));
+    new_volume->set_transformation(v->get_instance_transformation().get_matrix_no_offset().inverse());
+    const BoundingBoxf3 mesh_bb = new_volume->mesh().bounding_box();
     // Set the modifier position.
     auto offset = (type_name == "Slab") ?
         // Slab: Lift to print bed