import_step: do not assign labels to Compound.for_construction

src/build123d/importers.py

@@ -32,7 +32,7 @@
 import os
 from math import degrees
 from pathlib import Path
-from typing import TextIO, Union
+from typing import TextIO, Union, Optional
 
 import OCP.IFSelect
 from OCP.BRep import BRep_Builder
@@ -172,12 +172,14 @@ def get_col(obj: TopoDS_Shape) -> Quantity_ColorRGBA:
 
         return shape_color
 
-    def build_assembly(assembly: Compound) -> list[Shape]:
+    def build_assembly(
+        assembly: Compound, parent_tdf_label: Optional[TDF_Label] = None
+    ) -> list[Shape]:
         tdf_labels = TDF_LabelSequence()
-        if assembly.for_construction is None:
+        if parent_tdf_label is None:
             shape_tool.GetFreeShapes(tdf_labels)
         else:
-            shape_tool.GetComponents_s(assembly.for_construction, tdf_labels)
+            shape_tool.GetComponents_s(parent_tdf_label, tdf_labels)
 
         sub_shapes: list[Shape] = []
         for i in range(tdf_labels.Length()):
@@ -195,13 +197,12 @@ def build_assembly(assembly: Compound) -> list[Shape]:
                 sub_shape_loc = assembly.location.wrapped.Multiplied(sub_shape_loc)
             sub_shape: Shape = sub_shape_type()
             sub_shape.wrapped = downcast(topo_shape.Moved(sub_shape_loc))
-            sub_shape.for_construction = ref_tdf_label
             sub_shape.color = Color(get_color(topo_shape))
             sub_shape.label = get_name(ref_tdf_label)
 
             sub_shape.parent = assembly
             if shape_tool.IsAssembly_s(ref_tdf_label):
-                sub_shape.children = build_assembly(sub_shape)
+                sub_shape.children = build_assembly(sub_shape, ref_tdf_label)
             sub_shapes.append(sub_shape)
         return sub_shapes
 

src/build123d/topology.py

@@ -2312,7 +2312,8 @@ def __deepcopy__(self, memo) -> Self:
         cls = self.__class__
         result = cls.__new__(cls)
         memo[id(self)] = result
-        memo[id(self.wrapped)] = downcast(BRepBuilderAPI_Copy(self.wrapped).Shape())
+        if self.wrapped is not None:
+            memo[id(self.wrapped)] = downcast(BRepBuilderAPI_Copy(self.wrapped).Shape())
         for key, value in self.__dict__.items():
             setattr(result, key, copy.deepcopy(value, memo))
             if key == "joints":

tests/test_importers.py

@@ -108,6 +108,12 @@ def test_single_object(self):
         box = import_step("test.step")
         self.assertTrue(isinstance(box, Solid))
 
+    def test_move_single_object(self):
+        export_step(Solid.make_box(1, 1, 1), "test.step")
+        box = import_step("test.step")
+        box_moved = Pos(X=1) * box
+        self.assertEqual(tuple(box_moved.location.position), (1, 0, 0))
+
     def test_single_label_color(self):
         box_to_export = Solid.make_box(1, 1, 1)
         box_to_export.label = "box"