From bfb4312906bcbeb6dfa9bc7bd044cd5e2d593b5a Mon Sep 17 00:00:00 2001
From: falken10vdl <falken10vdl@gmail.com>
Date: Wed, 20 May 2026 08:53:57 +0200
Subject: [PATCH] Add has_underside_connection method to Model class and update
 wall regeneration logic

---
 src/bonsai/bonsai/bim/module/model/workspace.py | 5 +----
 src/bonsai/bonsai/core/tool.py                  | 1 +
 src/bonsai/bonsai/tool/model.py                 | 9 ++++++---
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/src/bonsai/bonsai/bim/module/model/workspace.py b/src/bonsai/bonsai/bim/module/model/workspace.py
index 5b08563dab..cd1fc449d0 100644
--- a/src/bonsai/bonsai/bim/module/model/workspace.py
+++ b/src/bonsai/bonsai/bim/module/model/workspace.py
@@ -1294,10 +1294,7 @@ class Hotkey(bpy.types.Operator, tool.Ifc.Operator):
                 bpy.ops.bim.generate_space()
             return
         if self.active_material_usage == "LAYER2":
-            if element and any(
-                rel.is_a("IfcRelConnectsElements") and rel.Description == "TOP"
-                for rel in element.ConnectedFrom
-            ):
+            if element and tool.Model.has_underside_connection(element):
                 bpy.ops.bim.regenerate_wall_to_underside()
             else:
                 bpy.ops.bim.recalculate_wall()
diff --git a/src/bonsai/bonsai/core/tool.py b/src/bonsai/bonsai/core/tool.py
index 8b94b5dc21..4c5df8edf1 100644
--- a/src/bonsai/bonsai/core/tool.py
+++ b/src/bonsai/bonsai/core/tool.py
@@ -683,6 +683,7 @@ class Model:
     def get_extrusion(cls, representation): pass
     def get_connected_slab_objs(cls, wall): pass
     def get_connected_wall_objs(cls, slab): pass
+    def has_underside_connection(cls, element): pass
     def get_manual_booleans(cls, element): pass
     def get_material_layer_parameters(cls, element): pass
     def get_slab_clipping_bmesh(cls, obj): pass
diff --git a/src/bonsai/bonsai/tool/model.py b/src/bonsai/bonsai/tool/model.py
index d8b78c599a..a697add69e 100644
--- a/src/bonsai/bonsai/tool/model.py
+++ b/src/bonsai/bonsai/tool/model.py
@@ -867,6 +867,11 @@ class Model(bonsai.core.tool.Model):
                     result.append(wall_obj)
         return result
 
+    @classmethod
+    def has_underside_connection(cls, element: ifcopenshell.entity_instance) -> bool:
+        """Return True if element has an IfcRelConnectsElements(TOP) relationship."""
+        return any(rel.is_a("IfcRelConnectsElements") and rel.Description == "TOP" for rel in element.ConnectedFrom)
+
     @classmethod
     def remove_wall_to_underside_booleans(cls, wall: ifcopenshell.entity_instance) -> None:
         """Remove all IfcBooleanResult items previously added by extend_walls_to_underside."""
@@ -2706,9 +2711,7 @@ class Model(bonsai.core.tool.Model):
 
             if operands:
                 body_repr = ifcopenshell.util.representation.get_representation(wall, "Model", "Body", "MODEL_VIEW")
-                booleans = ifcopenshell.api.geometry.add_boolean(
-                    ifc_file, first_item=extrusion, second_items=operands
-                )
+                booleans = ifcopenshell.api.geometry.add_boolean(ifc_file, first_item=extrusion, second_items=operands)
                 tool.Model.mark_manual_booleans(wall, booleans)
 
     @classmethod