Consider ifc2x3 in a358cff1b7 #6255

In ifc2x3 position is not optional, so we should reset it's coordinates instead.

src/bonsai/bonsai/bim/module/model/slab.py

@@ -331,9 +331,7 @@ class DumbSlabPlaner:
                 ifc_position = extrusion.Position
                 if perpendicular_offset == 0.0:
                     # Clean up possible previous offset.
-                    if ifc_position:
-                        extrusion.Position = None
-                        ifcopenshell.util.element.remove_deep2(ifc_file, ifc_position)
+                    tool.Model.reset_extrusion_position(extrusion)
                 else:
                     position = offset_direction * perpendicular_offset
                     if ifc_position:

src/bonsai/bonsai/tool/model.py

@@ -2064,6 +2064,21 @@ class Model(bonsai.core.tool.Model):
 
         extrusion.Position = new_position
 
+    @classmethod
+    def reset_extrusion_position(cls, extrusion: ifcopenshell.entity_instance) -> None:
+        ifc_file = extrusion.file
+
+        if ifc_file.schema == "IFC2X3":
+            # Position is not optional.
+            extrusion.Position.Location.Coordinates = (0.0, 0.0, 0.0)
+            return
+
+        position = extrusion.Position
+        if position is None:
+            return
+        extrusion.Position = None
+        ifcopenshell.util.element.remove_deep2(ifc_file, position)
+
     @classmethod
     def get_existing_x_angle(cls, extrusion: ifcopenshell.entity_instance) -> float:
         x, y, z = extrusion.ExtrudedDirection.DirectionRatios