From ffeda1970403dedeae27886959b8271fb0a5cdda Mon Sep 17 00:00:00 2001
From: gumyr <gumyr9@gmail.com>
Date: Thu, 26 Jun 2025 10:46:36 -0400
Subject: [PATCH] Added support for copying _base_wrapped, ensure _base_wrapped
 is not None

---
 src/build123d/topology/composite.py  | 39 ++++++++++++----------------
 src/build123d/topology/shape_core.py |  9 +++++++
 2 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/src/build123d/topology/composite.py b/src/build123d/topology/composite.py
index 7f58596..fb746b0 100644
--- a/src/build123d/topology/composite.py
+++ b/src/build123d/topology/composite.py
@@ -174,7 +174,7 @@ class MixinComposite(NodeMixin):
         - If no children or only one shape is present, the node is collapsed to a single wrapped shape.
         - This method should be called whenever child geometry or hierarchy changes.
         """
-        where_am_i_called_from()
+        # where_am_i_called_from(3)
         # print(f"{self=}, {self.location=}")
         for node in PostOrderIter(self):
             # print(f"{node=}, {node.location=}, {node.location_relative_to_parent=}")
@@ -800,41 +800,34 @@ class Compound(Mixin3D, MixinComposite, Shape[TopoDS_Compound]):
             children (Sequence[Shape], optional): assembly children. Defaults to None.
         """
         if isinstance(obj, TopoDS_Shape):
-            print("Making a Compound 1")
-            where_am_i_called_from(3)
-            self._base_wrapped = downcast(obj)
+            topods_compound = downcast(obj)
         elif isinstance(obj, Iterable):
-            print("Making a Compound 2")
-            where_am_i_called_from(3)
-            self._base_wrapped = _make_topods_compound_from_shapes(
+            topods_compound = _make_topods_compound_from_shapes(
                 [s.wrapped for s in obj]
             )
         elif obj is None:
-            print("Making a Compound 3")
-            self._base_wrapped = None
+            # When used in a Part/Sketch etc. context an empty Compound must
+            # have a wrapped attribute of None
+            topods_compound = None
         elif isinstance(obj, Assembly):
-            print("Making a Compound 4")
-            self._base_wrapped = obj.wrapped
+            topods_compound = obj.wrapped
         else:
             raise ValueError(f"Invalid obj of type {type(obj)}")
 
-        # if isinstance(obj, Iterable):
-        #     print("Making a Compound 1")
-        #     topods_compound = _make_topods_compound_from_shapes(
-        #         [s.wrapped for s in obj]
-        #     )
-        # else:
-        #     print("Making a Compound 2")
-        #     topods_compound = obj
-        # self._base_wrapped = topods_compound
-
         super().__init__(
-            obj=self._base_wrapped,
+            obj=topods_compound,
             label=label,
             color=color,
             parent=parent,
         )
-        self.location = Location()
+        # When used in an assembly context the base shape must be a valid
+        # compound in order to add children or set a parent
+        self._base_wrapped = (
+            _make_topods_compound_from_shapes([])
+            if topods_compound is None
+            else topods_compound
+        )
+
         self.material = "" if material is None else material
         self.joints = {} if joints is None else joints
 
diff --git a/src/build123d/topology/shape_core.py b/src/build123d/topology/shape_core.py
index 67d7593..eee15a6 100644
--- a/src/build123d/topology/shape_core.py
+++ b/src/build123d/topology/shape_core.py
@@ -908,6 +908,11 @@ class Shape(NodeMixin, Generic[TOPODS]):
                 reference.wrapped is not None
             )  # Ensure mypy knows reference.wrapped is not None
             reference.wrapped.TShape(self.wrapped.TShape())
+        if hasattr(self, "_base_wrapped") and self.wrapped is not None:
+            assert (
+                reference._base_wrapped is not None
+            )  # Ensure mypy knows reference.wrapped is not None
+            reference._base_wrapped.TShape(self._base_wrapped.TShape())
         return reference
 
     def __deepcopy__(self, memo) -> Self:
@@ -920,6 +925,10 @@ class Shape(NodeMixin, Generic[TOPODS]):
         memo[id(self)] = result
         if self.wrapped is not None:
             memo[id(self.wrapped)] = downcast(BRepBuilderAPI_Copy(self.wrapped).Shape())
+        if hasattr(self, "_base_wrapped") and self._base_wrapped is not None:
+            memo[id(self._base_wrapped)] = downcast(
+                BRepBuilderAPI_Copy(self._base_wrapped).Shape()
+            )
         for key, value in self.__dict__.items():
             if key == "topo_parent":
                 result.topo_parent = value