Why is there no way to move the center of gravity to the geometric center of a CollisionShape by code?

ignawesome · November 29, 2025, 11:16pm

Godot Version

4.5.1

Question

I want to be able to scale my procedural collision shapes by code, but if I can’t change the origin by code, the scaling makes it move away from the sprite.

I’ve looked through the documentation but I couldn’t find the way to do it. The origin point is not the transform.origin property as far as I can tell.

mrcdk · November 30, 2025, 9:42am

You can check the source code to see how the editor does it:

github.com/godotengine/godot

editor/scene/2d/abstract_polygon_2d_editor.cpp

7ed0b6167


      
          	_action_set_polygon(p_idx, _get_polygon(p_idx), p_polygon);
          }
          
          bool AbstractPolygon2DEditor::_has_resource() const {
          	return true;
          }
          
          void AbstractPolygon2DEditor::_create_resource() {
          }
          
          Vector2 AbstractPolygon2DEditor::_get_geometric_center() const {
          	int n_polygons = _get_polygon_count();
          
          	double cx = 0.0;
          	double cy = 0.0;
          	int n_subs = 0;
          	for (int i = 0; i < n_polygons; i++) {
          		const Vector<Vector2> &vertices = _get_polygon(i);
          		Vector<Vector<Point2>> decomp = ::Geometry2D::decompose_polygon_in_convex(vertices);
          		if (decomp.is_empty()) {
          			continue;

and

github.com/godotengine/godot

editor/scene/2d/abstract_polygon_2d_editor.cpp

7ed0b6167


      
          			button_edit->set_pressed(true);
          			button_delete->set_pressed(false);
          		} break;
          		case MODE_DELETE: {
          			_wip_close();
          			mode = MODE_DELETE;
          			button_create->set_pressed(false);
          			button_edit->set_pressed(false);
          			button_delete->set_pressed(true);
          		} break;
          		case CENTER_POLY: {
          			_wip_close();
          
          			EditorUndoRedoManager *undo_redo = EditorUndoRedoManager::get_singleton();
          			undo_redo->create_action(TTR("Move Origin to Geometric Center"));
          
          			Vector2 center = _get_geometric_center();
          
          			int n_polygons = _get_polygon_count();
          			for (int i = 0; i < n_polygons; i++) {
          				const Vector<Vector2> &vertices = _get_polygon(i);

ignawesome · December 2, 2025, 3:21am

Ah, yes, I was writing a proposal to expose the function in the scripting API when I saw some issues that linked to the abstract_polygon_2d_editor.cpp. Otherwise I wouldn’t have found it by myself. I implemented my own version in Gdscript but it’s not perfect.

Meanwhile, I made the proposal anyway: https://github.com/issues/created?issue=godotengine|godot-proposals|13761