Bonsai: batch array-duplicate + defensive guards

Replace N sequential duplicate_ifc_objects([parent]) calls in
_regenerate_array_body with one duplicate_ifc_object_n_times call
per layer, batching the fixed per-call overhead (snapshot gather,
UI refresh, decorator reload).

Guard batch_host_recut drain against dead StructRNA refs and prune
orphan array-child GUIDs at regen so outliner-delete of a
Bonsai-managed child cannot crash subsequent regenerate_array.

Recalculate walls after recreate_connections so Shift+D of
connected walls produces correct junction geometry without a
manual regen step.

Relates to #8088.

Generated with the assistance of an AI coding tool.

src/bonsai/bonsai/tool/geometry.py

@@ -163,13 +163,21 @@ class Geometry(bonsai.core.tool.Geometry):
                 cls._host_update_queue = {}
                 cls._host_recut_queue = {}
                 for voided_obj in update_queue.values():
-                    if not voided_obj or not voided_obj.data:
+                    try:
+                        if not voided_obj or not voided_obj.data:
+                            continue
+                    except ReferenceError:
+                        # Blender object was deleted while the batch was open
+                        # (e.g. user removed it via the outliner mid-op).
                         continue
                     if tool.Ifc.get_entity(voided_obj) is None:
                         continue
                     bpy.ops.bim.update_representation(obj=voided_obj.name)
                 for voided_obj, _ in recut_queue.values():
-                    if not voided_obj or not voided_obj.data:
+                    try:
+                        if not voided_obj or not voided_obj.data:
+                            continue
+                    except ReferenceError:
                         continue
                     if tool.Ifc.get_entity(voided_obj) is None:
                         continue
@@ -2481,99 +2489,16 @@ class Geometry(bonsai.core.tool.Geometry):
         old_obj_name_to_new_obj_name: dict[str, str] = {}
 
         for obj in objects_to_duplicate:
-            element = tool.Ifc.get_entity(obj)
-            if element:
-                if element.is_a("IfcAnnotation") and element.ObjectType == "DRAWING":
-                    tool.Blender.deselect_object(obj)
-                    continue  # For now, don't copy drawings until we stabilise a bit more. It's tricky.
-                elif tool.Geometry.is_locked(element):
-                    tool.Blender.deselect_object(obj)
-                    continue
-            elif tool.Geometry.is_representation_item(obj):
-                cls.duplicate_ifc_item(obj)
-                continue
-
-            tracked_opening_type = tool.Model.get_tracked_opening_type(obj)
-            is_tracked_opening = bool(tracked_opening_type)
-            keep_data_linked = linked and not element and not is_tracked_opening
-
-            # Prior to duplicating, sync the object placement to make decomposition recreation more stable.
-            cls.commit_placement_if_moved(obj, apply_scale=False)
-
-            new_obj = obj.copy()
-            temp_data = None
-
-            # Currently for optimization we do not apply pending changes (scale or changed .data)
-            # to the original and duplicated objects.
-            # Keep new object edited if original is.
-            if tool.Ifc.is_edited(obj, ignore_scale=True):
-                tool.Ifc.edit(new_obj)
-
-            if obj.data and not keep_data_linked:
-                # assure root.copy_class won't replace the previous mesh globally
-                temp_data = obj.data.copy()
-                new_obj.data = temp_data
-
-                # Unlink from previous boolean element
-                # and keep object tracked for decorations.
-                if is_tracked_opening:
-                    mprops = tool.Geometry.get_mesh_props(new_obj.data)
-                    mprops.ifc_boolean_id = 0
-                    tool.Root.add_tracked_opening(new_obj, tracked_opening_type)
-
-            if obj == active_object:
-                new_active_obj = new_obj
-            for collection in obj.users_collection:
-                collection.objects.link(new_obj)
-            obj.select_set(False)
-            new_obj.select_set(True)
-            old_obj_name_to_new_obj_name[obj.name] = new_obj.name
-
-            if not element:
-                continue
-
-            # clear object's collection so it will be able to have it's own
-            tool.Blender.get_object_bim_props(new_obj).collection = None
-            # copy the actual class
-            new = bonsai.core.root.copy_class(tool.Ifc, tool.Collector, tool.Geometry, tool.Root, obj=new_obj)
-
-            # clean up the orphaned mesh with ifc id of the original object to avoid confusion
-            # IfcGridAxis keeps the same mesh data (it's pointing to ifc id 0, so it's not a problem)
-            if new and temp_data and not new.is_a("IfcGridAxis"):
-                if new.is_a("IfcRelSpaceBoundary"):
-                    surface = new.ConnectionGeometry.SurfaceOnRelatingElement
-                    temp_data.name = f"0/{surface.id()}"
-                    tool.Ifc.link(surface, temp_data)
-                else:
-                    tool.Blender.remove_data_block(temp_data)
-
-            if new:
-                # TODO: handle array data for other cases of duplication
-                array_data = arrays_to_duplicate.get(obj, None)
-                tool.Model.handle_array_on_copied_element(new, array_data)
-                if array_data:
-                    for child in tool.Array.get_all_children_objects(new):
-                        child.select_set(True)
-
-                # TODO: add new array children to recreate their decomposition too
-                old_to_new[element] = [new]
-                if new.is_a("IfcRelSpaceBoundary"):
-                    tool.Boundary.decorate_boundary(new_obj)
-                # Slab-trim booleans (from extend_walls_to_underside) belong to
-                # the source wall's connection, not the copy. Strip them so the
-                # duplicate reverts to its pre-clip extrusion — mirrors the way
-                # filling rels are dropped while manual booleans persist on copy.
-                # Reload the body when something was stripped so the viewport
-                # immediately shows the unclipped geometry; otherwise the user
-                # sees a stale mesh until they Shift+G, which is easy to miss.
-                if new.is_a("IfcWall"):
-                    if tool.Model.strip_underside_booleans(new):
-                        tool.Model.reload_body_representation(new_obj)
-                    # HasOpenings rels don't follow object duplication, so
-                    # the duplicate's body must rebuild to match its current
-                    # opening set.
-                    else:
-                        tool.Model.regenerate_wall(new_obj)
+            new_active = cls._duplicate_ifc_object_once(
+                obj,
+                active_object,
+                linked,
+                arrays_to_duplicate,
+                old_to_new,
+                old_obj_name_to_new_obj_name,
+            )
+            if new_active is not None:
+                new_active_obj = new_active
 
         # Remap Blender parent relationships for duplicated objects
         for old_obj_name, new_obj_name in old_obj_name_to_new_obj_name.items():
@@ -2601,10 +2526,211 @@ class Geometry(bonsai.core.tool.Geometry):
         # Recreate decompositions
         tool.Duplicate.recreate_decompositions(decomposition_relationships, old_to_new)
         cls.remove_linked_aggregate_data(old_to_new)
+
+        # In-loop regenerate_wall runs before recreate_connections, so any new
+        # walls that just received an IfcRelConnectsPathElements have stale
+        # junction geometry — recalculate them now that their connection graph
+        # is complete.
+        cls._recalculate_walls_with_new_connections(old_to_new)
+
         bonsai.bim.handler.refresh_ui_data()
         tool.Root.reload_grid_decorator()
         return old_to_new, new_active_obj or active_object
 
+    @classmethod
+    def duplicate_ifc_object_n_times(
+        cls, source: bpy.types.Object, count: int
+    ) -> dict[ifcopenshell.entity_instance, list[ifcopenshell.entity_instance]]:
+        """N-way duplicate of a single source.
+
+        Same per-copy semantics as duplicate_ifc_objects (IFC class copy,
+        decomposition + connection recreation, body regen for walls), but
+        bypasses the set() dedupe and the arrays_to_duplicate pre-scan so
+        callers building a fresh array don't pay per-call overhead N times.
+        Returns the same old_to_new dict shape, with the source element
+        mapping to the N new entities."""
+        if count <= 0:
+            return {}
+
+        sources = {source}
+        decomposition_relationships = tool.Duplicate.get_decomposition_relationships(sources)
+        connection_relationships = tool.Duplicate.get_connection_relationships(sources)
+        port_connection_snapshot = tool.Duplicate.get_port_connection_relationships(sources)
+        old_to_new: dict[ifcopenshell.entity_instance, list[ifcopenshell.entity_instance]] = {}
+        old_obj_name_to_new_obj_name: dict[str, str] = {}
+
+        for _ in range(count):
+            cls._duplicate_ifc_object_once(
+                source,
+                None,
+                False,
+                {},
+                old_to_new,
+                old_obj_name_to_new_obj_name,
+                keep_source_selected=True,
+            )
+
+        for old_obj_name, new_obj_name in old_obj_name_to_new_obj_name.items():
+            new_obj = bpy.data.objects.get(new_obj_name)
+            if new_obj and new_obj.parent and new_obj.parent.name in old_obj_name_to_new_obj_name:
+                world_matrix = new_obj.matrix_world.copy()
+                new_parent_name = old_obj_name_to_new_obj_name[new_obj.parent.name]
+                new_parent = bpy.data.objects.get(new_parent_name)
+                if new_parent:
+                    new_obj.parent = new_parent
+                    new_obj.matrix_world = world_matrix
+
+        for old in old_to_new.keys():
+            if old.is_a("IfcElementAssembly"):
+                tool.Root.recreate_aggregate(old_to_new)
+
+        cls.remove_old_connections(old_to_new)
+        tool.Duplicate.recreate_connections(connection_relationships, old_to_new)
+        tool.Duplicate.recreate_port_connections(port_connection_snapshot, old_to_new)
+        tool.Duplicate.recreate_decompositions(decomposition_relationships, old_to_new)
+        cls.remove_linked_aggregate_data(old_to_new)
+        cls._recalculate_walls_with_new_connections(old_to_new)
+        bonsai.bim.handler.refresh_ui_data()
+        tool.Root.reload_grid_decorator()
+        return old_to_new
+
+    @classmethod
+    def _duplicate_ifc_object_once(
+        cls,
+        obj: bpy.types.Object,
+        active_object: Optional[bpy.types.Object],
+        linked: bool,
+        arrays_to_duplicate: dict[bpy.types.Object, Any],
+        old_to_new: dict[ifcopenshell.entity_instance, list[ifcopenshell.entity_instance]],
+        old_obj_name_to_new_obj_name: dict[str, str],
+        keep_source_selected: bool = False,
+    ) -> Optional[bpy.types.Object]:
+        """Per-source body of the duplicate flow. Mutates old_to_new and
+        old_obj_name_to_new_obj_name in place. Returns new_obj when obj is
+        the active_object, else None.
+
+        keep_source_selected: when True, skip the source deselect so batched
+        callers can run N iterations without N×2 select flips and without
+        needing a post-loop restore on the source."""
+        new_active_obj: Optional[bpy.types.Object] = None
+        element = tool.Ifc.get_entity(obj)
+        if element:
+            if element.is_a("IfcAnnotation") and element.ObjectType == "DRAWING":
+                tool.Blender.deselect_object(obj)
+                return None  # For now, don't copy drawings until we stabilise a bit more. It's tricky.
+            elif tool.Geometry.is_locked(element):
+                tool.Blender.deselect_object(obj)
+                return None
+        elif tool.Geometry.is_representation_item(obj):
+            cls.duplicate_ifc_item(obj)
+            return None
+
+        tracked_opening_type = tool.Model.get_tracked_opening_type(obj)
+        is_tracked_opening = bool(tracked_opening_type)
+        keep_data_linked = linked and not element and not is_tracked_opening
+
+        # Prior to duplicating, sync the object placement to make decomposition recreation more stable.
+        cls.commit_placement_if_moved(obj, apply_scale=False)
+
+        new_obj = obj.copy()
+        temp_data = None
+
+        # Currently for optimization we do not apply pending changes (scale or changed .data)
+        # to the original and duplicated objects.
+        # Keep new object edited if original is.
+        if tool.Ifc.is_edited(obj, ignore_scale=True):
+            tool.Ifc.edit(new_obj)
+
+        if obj.data and not keep_data_linked:
+            # assure root.copy_class won't replace the previous mesh globally
+            temp_data = obj.data.copy()
+            new_obj.data = temp_data
+
+            # Unlink from previous boolean element
+            # and keep object tracked for decorations.
+            if is_tracked_opening:
+                mprops = tool.Geometry.get_mesh_props(new_obj.data)
+                mprops.ifc_boolean_id = 0
+                tool.Root.add_tracked_opening(new_obj, tracked_opening_type)
+
+        if obj == active_object:
+            new_active_obj = new_obj
+        for collection in obj.users_collection:
+            collection.objects.link(new_obj)
+        if not keep_source_selected:
+            obj.select_set(False)
+        new_obj.select_set(True)
+        old_obj_name_to_new_obj_name[obj.name] = new_obj.name
+
+        if not element:
+            return new_active_obj
+
+        # clear object's collection so it will be able to have it's own
+        tool.Blender.get_object_bim_props(new_obj).collection = None
+        # copy the actual class
+        new = bonsai.core.root.copy_class(tool.Ifc, tool.Collector, tool.Geometry, tool.Root, obj=new_obj)
+
+        # clean up the orphaned mesh with ifc id of the original object to avoid confusion
+        # IfcGridAxis keeps the same mesh data (it's pointing to ifc id 0, so it's not a problem)
+        if new and temp_data and not new.is_a("IfcGridAxis"):
+            if new.is_a("IfcRelSpaceBoundary"):
+                surface = new.ConnectionGeometry.SurfaceOnRelatingElement
+                temp_data.name = f"0/{surface.id()}"
+                tool.Ifc.link(surface, temp_data)
+            else:
+                tool.Blender.remove_data_block(temp_data)
+
+        if new:
+            # TODO: handle array data for other cases of duplication
+            array_data = arrays_to_duplicate.get(obj, None)
+            tool.Model.handle_array_on_copied_element(new, array_data)
+            if array_data:
+                for child in tool.Array.get_all_children_objects(new):
+                    child.select_set(True)
+
+            # TODO: add new array children to recreate their decomposition too
+            old_to_new.setdefault(element, []).append(new)
+            if new.is_a("IfcRelSpaceBoundary"):
+                tool.Boundary.decorate_boundary(new_obj)
+            # Slab-trim booleans (from extend_walls_to_underside) belong to
+            # the source wall's connection, not the copy. Strip them so the
+            # duplicate reverts to its pre-clip extrusion — mirrors the way
+            # filling rels are dropped while manual booleans persist on copy.
+            # Reload the body when something was stripped so the viewport
+            # immediately shows the unclipped geometry; otherwise the user
+            # sees a stale mesh until they Shift+G, which is easy to miss.
+            if new.is_a("IfcWall"):
+                if tool.Model.strip_underside_booleans(new):
+                    tool.Model.reload_body_representation(new_obj)
+                # HasOpenings rels don't follow object duplication, so
+                # the duplicate's body must rebuild to match its current
+                # opening set.
+                else:
+                    tool.Model.regenerate_wall(new_obj)
+
+        return new_active_obj
+
+    @classmethod
+    def _recalculate_walls_with_new_connections(
+        cls, old_to_new: dict[ifcopenshell.entity_instance, list[ifcopenshell.entity_instance]]
+    ) -> None:
+        """Recalculate new IfcWall duplicates that just received an
+        ``IfcRelConnectsPathElements``. The in-loop ``regenerate_wall`` runs
+        before ``recreate_connections``, so wall body geometry doesn't reflect
+        the junction until this second pass."""
+        walls_to_recalc: list[bpy.types.Object] = []
+        for new_list in old_to_new.values():
+            for new_entity in new_list:
+                if not new_entity.is_a("IfcWall"):
+                    continue
+                if not (getattr(new_entity, "ConnectedTo", None) or getattr(new_entity, "ConnectedFrom", None)):
+                    continue
+                new_obj = tool.Ifc.get_object(new_entity)
+                if new_obj is not None:
+                    walls_to_recalc.append(new_obj)
+        if walls_to_recalc:
+            tool.Model.recalculate_walls(walls_to_recalc)
+
     @classmethod
     def duplicate_ifc_item(cls, obj: bpy.types.Object) -> None:
         props = tool.Geometry.get_geometry_props()

src/bonsai/bonsai/tool/model.py

@@ -1247,6 +1247,35 @@ class Model(bonsai.core.tool.Model):
         with tool.Geometry.batch_host_recut():
             cls._regenerate_array_body(parent_obj, data, array_layers_to_apply)
 
+    @classmethod
+    def _prune_orphan_array_children(cls, array: dict[str, Any]) -> None:
+        """Drop GUIDs from ``array['children']`` whose IFC entity or Blender
+        object is no longer alive, and cascade-remove the orphan IFC entity
+        if it still exists. Outliner / keyboard delete of a Bonsai-managed
+        object bypasses ``bim.delete``'s cascade, leaving dangling opening
+        and filling references that later confuse regen and crash the
+        ``batch_host_recut`` drain."""
+        live_guids: list[str] = []
+        ifc_file = tool.Ifc.get()
+        for guid in array["children"]:
+            try:
+                element = ifc_file.by_guid(guid)
+            except RuntimeError:
+                continue
+            obj = tool.Ifc.get_object(element)
+            try:
+                is_live = obj is not None and obj.data is not None
+            except ReferenceError:
+                is_live = False
+            if is_live:
+                live_guids.append(guid)
+                continue
+            try:
+                ifcopenshell.api.root.remove_product(ifc_file, product=element)
+            except (RuntimeError, ifcopenshell.Error):
+                pass
+        array["children"] = live_guids
+
     @classmethod
     def _regenerate_array_body(
         cls, parent_obj: bpy.types.Object, data: list[dict[str, Any]], array_layers_to_apply: Iterable[int]
@@ -1262,6 +1291,7 @@ class Model(bonsai.core.tool.Model):
         obj_stack = [parent_obj]
 
         for array_i, array in enumerate(data):
+            cls._prune_orphan_array_children(array)
             child_i = 0
             existing_children = set(array["children"])
             total_existing_children = len(array["children"])
@@ -1275,6 +1305,14 @@ class Model(bonsai.core.tool.Model):
             else:
                 base_offset = Vector([array["x"], array["y"], array["z"]]) * unit_scale
 
+            target_new_in_this_layer = (array["count"] - 1) * len(obj_stack)
+            missing_count = max(0, target_new_in_this_layer - total_existing_children)
+            new_entities_pool: list[ifcopenshell.entity_instance] = []
+            if missing_count > 0:
+                batch_old_to_new = tool.Geometry.duplicate_ifc_object_n_times(parent_obj, missing_count)
+                new_entities_pool = batch_old_to_new.get(parent_element, [])
+            new_entities_iter = iter(new_entities_pool)
+
             for i in range(array["count"]):
                 if i == 0:
                     continue
@@ -1292,8 +1330,13 @@ class Model(bonsai.core.tool.Model):
                         child_obj = tool.Ifc.get_object(child_element)
                         assert child_obj
                     except (IndexError, RuntimeError, AssertionError):
-                        old_to_new, _ = tool.Geometry.duplicate_ifc_objects([parent_obj])
-                        child_element = next(iter(old_to_new.values()))[0]
+                        try:
+                            child_element = next(new_entities_iter)
+                        except StopIteration:
+                            # Stale-GUID mid-list left the pool exhausted; fall back
+                            # to a one-off duplicate so the layer can still complete.
+                            old_to_new, _ = tool.Geometry.duplicate_ifc_objects([parent_obj])
+                            child_element = next(iter(old_to_new.values()))[0]
                         child_obj = tool.Ifc.get_object(child_element)
 
                     # add child pset
@@ -1361,13 +1404,6 @@ class Model(bonsai.core.tool.Model):
             tool.Ifc.get(), pset=pset, properties={"Data": json_data, "Parent": parent_element.GlobalId}
         )
 
-        # Post-condition: parent is selected on return. duplicate_ifc_objects
-        # deselects the source on every call inside the regen loop; without
-        # this restore, callers get a deselected parent for arrays with N >= 2.
-        # TODO: batch the per-child duplicate_ifc_objects([parent]) calls into
-        # a single N-way duplicate — N depsgraph churns + N select/deselect
-        # flips is wasteful, and a batched duplicate would also remove the
-        # need for this restore.
         parent_obj.select_set(True)
 
     @classmethod

src/bonsai/test/bim/module/model/test_array_duplicate_batched.py

@@ -0,0 +1,376 @@
+# Bonsai - OpenBIM Blender Add-on
+# Copyright (C) 2026
+#
+# This file is part of Bonsai.
+#
+# Bonsai is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Bonsai is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was generated with the assistance of an AI coding tool.
+
+"""Tests for the batched array-duplicate path.
+
+`tool.Geometry.duplicate_ifc_object_n_times` lifts the per-call overhead of
+`duplicate_ifc_objects` (snapshot, UI refresh, decorator reload, select
+flips) out of the per-child loop in `_regenerate_array_body`. These tests
+pin three contracts:
+
+1. N-way batched duplicate produces N distinct entities mapped from the
+   source under `old_to_new[source_element]`, and the source object stays
+   selected throughout (no per-iteration deselect).
+2. Per-layer batching collapses the N independent UI refreshes into one.
+3. End-to-end array regen still yields the same number and shape of
+   children as the per-call baseline."""
+
+import json
+from unittest.mock import patch
+
+import bpy
+import ifcopenshell
+import pytest
+
+import bonsai.tool as tool
+from test.bim.bootstrap import NewFile
+
+pytestmark = pytest.mark.model
+
+
+def _build_actuator(name: str = "Actuator") -> tuple[bpy.types.Object, ifcopenshell.entity_instance]:
+    """Minimal IfcActuator + cube — matches the test_array_batch_recut.py shape."""
+    bpy.ops.bim.create_project()
+    bpy.ops.mesh.primitive_cube_add()
+    obj = bpy.context.active_object
+    obj.name = name
+    rprops = tool.Root.get_root_props()
+    rprops.ifc_product = "IfcElement"
+    bpy.ops.bim.assign_class(ifc_class="IfcActuator", predefined_type="ELECTRICACTUATOR", userdefined_type="")
+    element = tool.Ifc.get_entity(obj)
+    return obj, element
+
+
+def _build_actuator_with_array_pset(
+    count: int, x: float = 1.0
+) -> tuple[bpy.types.Object, ifcopenshell.entity_instance, list[dict]]:
+    obj, element = _build_actuator()
+    parent_data = [
+        {
+            "children": [],
+            "count": count,
+            "method": "OFFSET",
+            "x": x,
+            "y": 0.0,
+            "z": 0.0,
+            "use_local_space": False,
+            "sync_children": False,
+        }
+    ]
+    pset = ifcopenshell.api.pset.add_pset(tool.Ifc.get(), product=element, name="BBIM_Array")
+    ifcopenshell.api.pset.edit_pset(
+        tool.Ifc.get(),
+        pset=pset,
+        properties={"Data": json.dumps(parent_data), "Parent": element.GlobalId},
+    )
+    return obj, element, parent_data
+
+
+class TestDuplicateIfcObjectNTimes(NewFile):
+    def test_returns_empty_dict_for_zero_count(self):
+        obj, _ = _build_actuator()
+        result = tool.Geometry.duplicate_ifc_object_n_times(obj, 0)
+        assert result == {}
+
+    def test_returns_empty_dict_for_negative_count(self):
+        obj, _ = _build_actuator()
+        result = tool.Geometry.duplicate_ifc_object_n_times(obj, -3)
+        assert result == {}
+
+    def test_produces_n_distinct_entities(self):
+        obj, element = _build_actuator()
+        result = tool.Geometry.duplicate_ifc_object_n_times(obj, 5)
+        new_entities = result.get(element)
+        assert new_entities is not None
+        assert len(new_entities) == 5
+        assert len({e.id() for e in new_entities}) == 5
+        for new_entity in new_entities:
+            assert new_entity.is_a("IfcActuator")
+            assert new_entity.GlobalId != element.GlobalId
+
+    def test_source_stays_selected_after_batch(self):
+        obj, _ = _build_actuator()
+        obj.select_set(True)
+        tool.Geometry.duplicate_ifc_object_n_times(obj, 4)
+        assert obj in bpy.context.selected_objects, "source object must remain selected across batched duplicates"
+
+    def test_each_new_entity_has_blender_object(self):
+        obj, element = _build_actuator()
+        result = tool.Geometry.duplicate_ifc_object_n_times(obj, 3)
+        for new_entity in result[element]:
+            new_obj = tool.Ifc.get_object(new_entity)
+            assert new_obj is not None
+            assert new_obj is not obj
+
+
+class TestBatchedRefreshUIDataCallCount(NewFile):
+    def test_n_times_calls_refresh_ui_data_once(self):
+        obj, _ = _build_actuator()
+        with patch("bonsai.bim.handler.refresh_ui_data") as refresh_mock:
+            tool.Geometry.duplicate_ifc_object_n_times(obj, 8)
+        assert (
+            refresh_mock.call_count == 1
+        ), f"batched 8-way duplicate must call refresh_ui_data once, got {refresh_mock.call_count}"
+
+    def test_n_times_calls_reload_grid_decorator_once(self):
+        obj, _ = _build_actuator()
+        with patch.object(tool.Root, "reload_grid_decorator") as reload_mock:
+            tool.Geometry.duplicate_ifc_object_n_times(obj, 8)
+        assert reload_mock.call_count == 1
+
+
+class TestRegenerateArrayEndToEnd(NewFile):
+    def test_regenerate_array_creates_expected_children(self):
+        obj, element, parent_data = _build_actuator_with_array_pset(count=8)
+        bpy.context.view_layer.objects.active = obj
+        tool.Model.regenerate_array(obj, parent_data)
+
+        layer = parent_data[0]
+        assert len(layer["children"]) == 7, "8-element array means 7 new children (parent + 7)"
+        for child_guid in layer["children"]:
+            child_element = tool.Ifc.get().by_guid(child_guid)
+            assert child_element is not None
+            assert child_element.is_a("IfcActuator")
+            child_pset = ifcopenshell.util.element.get_pset(child_element, "BBIM_Array")
+            assert child_pset is not None
+            assert child_pset["Parent"] == element.GlobalId
+
+    def test_regenerate_array_parent_stays_selected(self):
+        obj, element, parent_data = _build_actuator_with_array_pset(count=4)
+        bpy.context.view_layer.objects.active = obj
+        obj.select_set(True)
+        tool.Model.regenerate_array(obj, parent_data)
+        assert (
+            obj in bpy.context.selected_objects
+        ), "regenerate_array must leave parent_obj selected on return (post-condition)"
+
+    def test_regen_operator_leaves_only_parent_selected_and_active(self):
+        """Post-condition parity between grow and shrink for the user-facing
+        ``bim.regenerate_array`` operator: only the parent is selected + active;
+        every child is deselected. Pre-fix the grow path left new children
+        selected, creating inconsistency with the shrink path.
+
+        Scoped to the operator, not the tool method — ``remove_array`` and
+        ``apply_array`` also invoke ``tool.Model.regenerate_array`` internally
+        but expect a different post-selection state (children stay selected
+        for user follow-up work)."""
+        obj, element, parent_data = _build_actuator_with_array_pset(count=6)
+        bpy.context.view_layer.objects.active = obj
+        obj.select_set(True)
+        bpy.ops.bim.regenerate_array()
+
+        assert obj in bpy.context.selected_objects
+        assert bpy.context.view_layer.objects.active is obj
+        parent_pset = ifcopenshell.util.element.get_pset(element, "BBIM_Array")
+        parent_data_after = json.loads(parent_pset["Data"])
+        for child_guid in parent_data_after[0]["children"]:
+            child_element = tool.Ifc.get().by_guid(child_guid)
+            child_obj = tool.Ifc.get_object(child_element)
+            assert (
+                child_obj not in bpy.context.selected_objects
+            ), f"child {child_obj.name} must be deselected on regenerate_array return"
+
+    def test_regen_operator_after_shrink_still_leaves_only_parent_selected(self):
+        obj, element, parent_data = _build_actuator_with_array_pset(count=6)
+        bpy.context.view_layer.objects.active = obj
+        bpy.ops.bim.regenerate_array()
+
+        parent_pset = ifcopenshell.util.element.get_pset(element, "BBIM_Array")
+        arrays = json.loads(parent_pset["Data"])
+        arrays[0]["count"] = 3
+        pset_entity = tool.Ifc.get().by_id(parent_pset["id"])
+        ifcopenshell.api.pset.edit_pset(tool.Ifc.get(), pset=pset_entity, properties={"Data": json.dumps(arrays)})
+        bpy.ops.bim.regenerate_array()
+
+        assert obj in bpy.context.selected_objects
+        assert bpy.context.view_layer.objects.active is obj
+        parent_pset = ifcopenshell.util.element.get_pset(element, "BBIM_Array")
+        arrays_after = json.loads(parent_pset["Data"])
+        for child_guid in arrays_after[0]["children"]:
+            child_element = tool.Ifc.get().by_guid(child_guid)
+            child_obj = tool.Ifc.get_object(child_element)
+            assert child_obj not in bpy.context.selected_objects
+
+    def test_regenerate_array_child_positions_match_offset(self):
+        obj, element, parent_data = _build_actuator_with_array_pset(count=4, x=2.5)
+        bpy.context.view_layer.objects.active = obj
+        parent_x = obj.matrix_world.translation.x
+        tool.Model.regenerate_array(obj, parent_data)
+
+        layer = parent_data[0]
+        for i, child_guid in enumerate(layer["children"], start=1):
+            child_element = tool.Ifc.get().by_guid(child_guid)
+            child_obj = tool.Ifc.get_object(child_element)
+            expected_x = parent_x + 2.5 * i
+            assert child_obj.matrix_world.translation.x == pytest.approx(
+                expected_x
+            ), f"child {i}: expected x≈{expected_x}, got {child_obj.matrix_world.translation.x}"
+
+
+class TestRegenerateArrayUIRefreshCoalesces(NewFile):
+    def test_n_children_grow_calls_refresh_ui_data_once_per_layer(self):
+        obj, element, parent_data = _build_actuator_with_array_pset(count=8)
+        bpy.context.view_layer.objects.active = obj
+        with patch("bonsai.bim.handler.refresh_ui_data") as refresh_mock:
+            tool.Model.regenerate_array(obj, parent_data)
+        assert refresh_mock.call_count == 1, (
+            "growing an array layer from 0 to 7 children must call refresh_ui_data once, "
+            f"got {refresh_mock.call_count}"
+        )
+
+    def test_n_children_grow_calls_reload_grid_decorator_once_per_layer(self):
+        obj, element, parent_data = _build_actuator_with_array_pset(count=8)
+        bpy.context.view_layer.objects.active = obj
+        with patch.object(tool.Root, "reload_grid_decorator") as reload_mock:
+            tool.Model.regenerate_array(obj, parent_data)
+        assert reload_mock.call_count == 1
+
+
+class TestRecalculateWallsWithNewConnections(NewFile):
+    """Pins the post-connection wall recalc: after ``recreate_connections``
+    wires new IfcRelConnectsPathElements onto duplicated walls, the wall
+    bodies must be re-recalculated because the in-loop ``regenerate_wall``
+    fired before the connections existed. Otherwise the junction geometry
+    stays stale and the user has to manually regen."""
+
+    def test_walls_with_new_connections_are_recalculated(self):
+        from unittest.mock import Mock
+
+        wall_new = Mock()
+        wall_new.is_a = lambda c: c == "IfcWall"
+        wall_new.ConnectedTo = [Mock()]
+        wall_new.ConnectedFrom = []
+
+        wall_obj = Mock()
+        old_to_new = {Mock(): [wall_new]}
+
+        with patch.object(tool.Ifc, "get_object", return_value=wall_obj), patch.object(
+            tool.Model, "recalculate_walls"
+        ) as recalc_mock:
+            tool.Geometry._recalculate_walls_with_new_connections(old_to_new)
+
+        assert recalc_mock.call_count == 1
+        assert recalc_mock.call_args.args[0] == [wall_obj]
+
+    def test_walls_without_connections_are_skipped(self):
+        from unittest.mock import Mock
+
+        wall_new = Mock()
+        wall_new.is_a = lambda c: c == "IfcWall"
+        wall_new.ConnectedTo = []
+        wall_new.ConnectedFrom = []
+
+        old_to_new = {Mock(): [wall_new]}
+
+        with patch.object(tool.Ifc, "get_object", return_value=Mock()), patch.object(
+            tool.Model, "recalculate_walls"
+        ) as recalc_mock:
+            tool.Geometry._recalculate_walls_with_new_connections(old_to_new)
+
+        assert recalc_mock.call_count == 0, "walls with no new connections must not trigger a recalc pass"
+
+    def test_non_wall_entities_are_skipped(self):
+        from unittest.mock import Mock
+
+        actuator_new = Mock()
+        actuator_new.is_a = lambda c: c == "IfcActuator"
+        actuator_new.ConnectedTo = [Mock()]
+
+        old_to_new = {Mock(): [actuator_new]}
+
+        with patch.object(tool.Ifc, "get_object", return_value=Mock()), patch.object(
+            tool.Model, "recalculate_walls"
+        ) as recalc_mock:
+            tool.Geometry._recalculate_walls_with_new_connections(old_to_new)
+
+        assert recalc_mock.call_count == 0
+
+    def test_multiple_new_walls_collected_into_one_call(self):
+        from unittest.mock import Mock
+
+        wall_a_new = Mock()
+        wall_a_new.is_a = lambda c: c == "IfcWall"
+        wall_a_new.ConnectedTo = [Mock()]
+        wall_a_new.ConnectedFrom = []
+        wall_b_new = Mock()
+        wall_b_new.is_a = lambda c: c == "IfcWall"
+        wall_b_new.ConnectedTo = []
+        wall_b_new.ConnectedFrom = [Mock()]
+
+        objs = {wall_a_new: Mock(), wall_b_new: Mock()}
+        old_to_new = {Mock(): [wall_a_new], Mock(): [wall_b_new]}
+
+        with patch.object(tool.Ifc, "get_object", side_effect=lambda e: objs.get(e)), patch.object(
+            tool.Model, "recalculate_walls"
+        ) as recalc_mock:
+            tool.Geometry._recalculate_walls_with_new_connections(old_to_new)
+
+        assert recalc_mock.call_count == 1
+        assert set(recalc_mock.call_args.args[0]) == {objs[wall_a_new], objs[wall_b_new]}
+
+
+class TestOrphanArrayChildPrune(NewFile):
+    """Outliner / keyboard delete of a Bonsai-managed array child bypasses
+    ``bim.delete``'s cascade, leaving the IFC entity and its opening / filling
+    refs behind. Regen must prune these orphans before the main loop or the
+    stale registry entry corrupts the ``batch_host_recut`` drain."""
+
+    def test_orphan_ifc_entity_pruned_from_children_list(self):
+        obj, element, parent_data = _build_actuator_with_array_pset(count=4)
+        bpy.context.view_layer.objects.active = obj
+        tool.Model.regenerate_array(obj, parent_data)
+        assert len(parent_data[0]["children"]) == 3
+
+        orphan_guid = parent_data[0]["children"][1]
+        orphan_element = tool.Ifc.get().by_guid(orphan_guid)
+        orphan_obj = tool.Ifc.get_object(orphan_element)
+        assert orphan_obj is not None
+        bpy.data.objects.remove(orphan_obj, do_unlink=True)
+
+        tool.Model.regenerate_array(obj, parent_data)
+
+        assert (
+            orphan_guid not in parent_data[0]["children"]
+        ), "orphan GUID must be pruned from array['children'] once its Blender object is dead"
+        try:
+            still_there = tool.Ifc.get().by_guid(orphan_guid)
+        except RuntimeError:
+            still_there = None
+        assert still_there is None, "orphan IFC entity must be cascade-removed, not left as a leak"
+
+    def test_regen_completes_when_child_deleted_outside_bim_cascade(self):
+        obj, element, parent_data = _build_actuator_with_array_pset(count=6)
+        bpy.context.view_layer.objects.active = obj
+        tool.Model.regenerate_array(obj, parent_data)
+
+        victim_guid = parent_data[0]["children"][2]
+        victim_element = tool.Ifc.get().by_guid(victim_guid)
+        victim_obj = tool.Ifc.get_object(victim_element)
+        bpy.data.objects.remove(victim_obj, do_unlink=True)
+
+        tool.Model.regenerate_array(obj, parent_data)
+
+        assert len(parent_data[0]["children"]) == 5, "regen must rebuild to the target count after pruning the orphan"
+        for guid in parent_data[0]["children"]:
+            child = tool.Ifc.get().by_guid(guid)
+            child_obj = tool.Ifc.get_object(child)
+            assert child_obj is not None, "every surviving child must have a live Blender object"
+
+

src/bonsai/test/tool/test_geometry_batch_host_recut.py

@@ -164,6 +164,62 @@ def test_stale_element_skipped_at_drain():
     assert recut.call_count == 0
 
 
+class _DeadStructRNA:
+    """Simulates a Blender object whose StructRNA has been removed — every
+    attribute access raises ReferenceError. Enqueue this as voided_obj to
+    reproduce the outliner-mid-batch-delete crash."""
+
+    def __getattr__(self, name):
+        raise ReferenceError("StructRNA of type Object has been removed")
+
+    def __bool__(self):
+        raise ReferenceError("StructRNA of type Object has been removed")
+
+
+def test_dead_structrna_recut_skipped_at_drain():
+    """Blender object is deleted while the batch is open (outliner delete +
+    manual DEL bypass the bim.delete cascade). The drain must skip it silently
+    — not raise — so unrelated hosts in the same batch still get their recut."""
+    from bonsai import tool
+
+    dead_obj = _DeadStructRNA()
+    live_obj = _mock_voided_obj("LiveWall")
+    rep = Mock()
+
+    def get_entity(obj):
+        # Called only when the guard clears — for the dead ref, guard short-circuits first.
+        return _mock_element(2)
+
+    with patch("bonsai.core.geometry.switch_representation") as recut, patch.object(
+        tool.Ifc, "get_entity", side_effect=get_entity
+    ), patch.object(tool.Geometry, "get_active_representation", return_value=rep):
+        with tool.Geometry.batch_host_recut():
+            tool.Geometry._host_recut_queue[999] = (dead_obj, rep)
+            tool.Geometry.recut_host(live_obj, rep)
+
+    assert recut.call_count == 1, "live host must still get its recut despite a dead sibling in the queue"
+    drained_obj = recut.call_args.kwargs["obj"]
+    assert drained_obj is live_obj
+
+
+def test_dead_structrna_update_skipped_at_drain():
+    """Same guarantee for update_representation drain path."""
+    from bonsai import tool
+
+    dead_obj = _DeadStructRNA()
+    live_obj = _mock_voided_obj("LiveWall")
+    bpy_ops_mock = Mock()
+
+    with patch("bonsai.tool.geometry.bpy.ops", new=bpy_ops_mock), patch.object(
+        tool.Ifc, "get_entity", return_value=_mock_element(42)
+    ), patch.object(tool.Geometry, "get_active_representation", return_value=Mock()):
+        with tool.Geometry.batch_host_recut():
+            tool.Geometry._host_update_queue[999] = dead_obj
+            tool.Geometry.update_host_representation(live_obj)
+
+    assert bpy_ops_mock.bim.update_representation.call_count == 1
+
+
 def test_exception_inside_batch_still_resets_state():
     from bonsai import tool