Shift-click add-opening preserves filling placement

The regular bim.add_opening click on the host-add-opening gizmo
(wall + door/window co-selected) routes through
FilledOpeningGenerator.generate, which snaps the filling to the
wall's reference-line axis, optionally rotates 180° when the
filling sits on the opposite side, and re-applies an rl1 / rl2
Z-elevation default. That is the right default for "drag a fresh
door onto a wall and let the model place it for me", but defeats
the workflow where the user has already positioned the filling
precisely (e.g. snapped to a window in an adjacent wall, copy-
pasted at an exact Z, aligned to a reference object).

Holding SHIFT while clicking the gizmo now opts into a
"preserve placement" mode: the filling stays at its current
matrix_world and the opening is created at the filling's existing
position. The opening / filling rels and representation work are
unchanged — only the snap-to-axis branch is skipped, so the IFC
graph is identical to the regular click; only the spatial
position of the filling differs (user-chosen vs auto-snapped).

Implementation:

* bim/module/void/operator.py: AddOpening gains a hidden
  preserve_placement BoolProperty + an invoke() that sets it from
  event.shift. The call into FilledOpeningGenerator.generate
  forwards the flag. bl_description documents the SHIFT modifier
  so it surfaces in F3 search / hover tooltip.

* bim/module/model/opening.py: FilledOpeningGenerator.generate
  accepts preserve_placement (default False — backwards-compatible
  with the other caller, tool.Model.add_filled_opening). The
  voided_obj.data-gated snap block (raycast + axis projection +
  rl-Z default + filling_obj.matrix_world write) skips entirely
  when the flag is True. The opening's matrix_world reads from
  filling_obj.matrix_world below the gate, so the opening lands
  at the filling's preserved position automatically.

Generated with the assistance of an AI coding tool.

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

@@ -229,9 +229,15 @@ class FilledOpeningGenerator:
         filling_obj: bpy.types.Object,
         voided_obj: bpy.types.Object,
         target: Optional[Vector] = None,
+        preserve_placement: bool = False,
     ) -> Union[None, str]:
         """
         :param target: Target opening position. If ommited, cursor position is used.
+        :param preserve_placement: If True, keep ``filling_obj.matrix_world`` as-is
+            and skip the snap-to-wall-axis / rl1-rl2 Z-default logic. The opening
+            is still created at the filling's current world position. Useful
+            when the caller (e.g. the SHIFT-add-opening gizmo flow) has
+            already positioned the filling intentionally.
         :return: None if there was no errors, otherwise returns a string with error message.
         """
         props = tool.Model.get_model_props()
@@ -253,7 +259,7 @@ class FilledOpeningGenerator:
             should_set_z_level = False
 
         # Sometimes, the voided_obj may be an aggregate, which won't have any representation.
-        if voided_obj.data:
+        if not preserve_placement and voided_obj.data:
             raycast = voided_obj.closest_point_on_mesh(voided_obj.matrix_world.inverted() @ target, distance=0.01)
             if not raycast[0]:
                 target = filling_obj.matrix_world.translation.copy()

src/bonsai/bonsai/bim/module/void/operator.py

@@ -36,9 +36,17 @@ class AddOpening(bpy.types.Operator, tool.Ifc.Operator):
     bl_description = (
         "Apply opening objects to an Element.\n\n"
         "The Element and the openings to be applied should be selected. The order of selection is not important.\n"
-        "Opening can be just a Blender mesh object."
+        "Opening can be just a Blender mesh object.\n\n"
+        "Shift+click: keep the filling at its current matrix_world — skip the wall-axis snap "
+        "and the rl1/rl2 Z-elevation default that the regular click applies."
     )
 
+    # Toggled by ``invoke`` when the user holds SHIFT during a gizmo / hotkey
+    # click. Forwards to ``FilledOpeningGenerator.generate`` which gates the
+    # snap-to-wall-axis block on it. HIDDEN + SKIP_SAVE so it doesn't surface
+    # in the F6 redo panel or persist into saved keymaps.
+    preserve_placement: bpy.props.BoolProperty(default=False, options={"HIDDEN", "SKIP_SAVE"})
+
     @classmethod
     def poll(cls, context):
         if len(context.selected_objects) < 2:
@@ -46,6 +54,10 @@ class AddOpening(bpy.types.Operator, tool.Ifc.Operator):
             return False
         return True
 
+    def invoke(self, context, event):
+        self.preserve_placement = bool(event.shift)
+        return self.execute(context)
+
     def _execute(self, context):
         selected_objects = context.selected_objects
         target_object = selected_objects[0]
@@ -68,7 +80,12 @@ class AddOpening(bpy.types.Operator, tool.Ifc.Operator):
                 elif not element1.is_a("IfcOpeningElement") and not element2.is_a("IfcOpeningElement"):
                     if element1.is_a("IfcWindow") or element1.is_a("IfcDoor"):  # Add a fill to an element.
                         obj1, obj2 = obj2, obj1
-                    FilledOpeningGenerator().generate(obj2, obj1, target=obj2.matrix_world.translation)
+                    FilledOpeningGenerator().generate(
+                        obj2,
+                        obj1,
+                        target=obj2.matrix_world.translation,
+                        preserve_placement=self.preserve_placement,
+                    )
                     continue
                 elif element1.is_a("IfcOpeningElement") or element2.is_a("IfcOpeningElement"):
                     if element1.is_a("IfcOpeningElement"):  # Reassign an opening to another element.