Remove one level of hierarchy in STEP export

Do not hard code root name if unspecified

Author: lorenzncode

cadquery/occ_impl/assembly.py

@@ -140,7 +140,7 @@ def toCAF(
     mesh: bool = False,
     tolerance: float = 1e-3,
     angularTolerance: float = 0.1,
-) -> Tuple[TDF_Label, TDocStd_Document]:
+) -> TDocStd_Document:
 
     # prepare a doc
     app = XCAFApp_Application.GetApplication_s()
@@ -152,10 +152,6 @@ def toCAF(
     tool.SetAutoNaming_s(False)
     ctool = XCAFDoc_DocumentTool.ColorTool_s(doc.Main())
 
-    # add root
-    top = tool.NewShape()
-    TDataStd_Name.Set_s(top, TCollection_ExtendedString("CQ assembly"))
-
     # used to store labels with unique part-color combinations
     unique_objs: Dict[Tuple[Color, AssemblyObjects], TDF_Label] = {}
     # used to cache unique, possibly meshed, compounds; allows to avoid redundant meshing operations if same object is referenced multiple times in an assy
@@ -207,15 +203,16 @@ def _toCAF(el, ancestor, color):
         for child in el.children:
             _toCAF(child, subassy, current_color)
 
-        # add the current subassy to the higher level assy
-        tool.AddComponent(ancestor, subassy, el.loc.wrapped)
+        if ancestor:
+            # add the current subassy to the higher level assy
+            tool.AddComponent(ancestor, subassy, el.loc.wrapped)
 
     # process the whole assy recursively
-    _toCAF(assy, top, None)
+    _toCAF(assy, None, None)
 
     tool.UpdateAssemblies()
 
-    return top, doc
+    return doc
 
 
 def toVTK(

cadquery/occ_impl/exporters/assembly.py

@@ -50,7 +50,7 @@ def exportAssembly(assy: AssemblyProtocol, path: str, **kwargs) -> bool:
         pcurves = 0
     precision_mode = kwargs["precision_mode"] if "precision_mode" in kwargs else 0
 
-    _, doc = toCAF(assy, True)
+    doc = toCAF(assy, True)
 
     session = XSControl_WorkSession()
     writer = STEPCAFControl_Writer(session, False)
@@ -75,7 +75,7 @@ def exportCAF(assy: AssemblyProtocol, path: str) -> bool:
     name, ext = os.path.splitext(fname)
     ext = ext[1:] if ext[0] == "." else ext
 
-    _, doc = toCAF(assy)
+    doc = toCAF(assy)
     app = XCAFApp_Application.GetApplication_s()
 
     store = XmlDrivers_DocumentStorageDriver(
@@ -167,7 +167,7 @@ def exportGLTF(
     orig_loc = assy.loc
     assy.loc *= Location((0, 0, 0), (1, 0, 0), -90)
 
-    _, doc = toCAF(assy, True, True, tolerance, angularTolerance)
+    doc = toCAF(assy, True, True, tolerance, angularTolerance)
 
     writer = RWGltf_CafWriter(TCollection_AsciiString(path), binary)
     result = writer.Perform(

tests/test_assembly.py

@@ -479,6 +479,21 @@ def test_assembly(simple_assy, nested_assy):
     assert kvs[-1][0] == "TOP"
 
 
+@pytest.mark.parametrize(
+    "assy_fixture, root_name", [("simple_assy", None), ("nested_assy", "TOP")],
+)
+def test_assy_root_name(assy_fixture, root_name, request):
+    assy = request.getfixturevalue(assy_fixture)
+    doc = toCAF(assy, True)
+    root = get_doc_nodes(doc, False)[0]
+    if root_name:
+        assert root["name"] == root_name
+    else:
+        # When a name is not user-specifed, the name is assigned a UUID
+        m = re.findall(r"[0-9a-f]+", root["name"])
+        assert list(map(len, m)) == [8, 4, 4, 4, 12]
+
+
 def test_step_export(nested_assy, tmp_path_factory):
     # Use a temporary directory
     tmpdir = tmp_path_factory.mktemp("out")
@@ -600,7 +615,7 @@ def test_save_raises(nested_assy):
 def test_leaf_node_count(assy_fixture, count, request):
 
     assy = request.getfixturevalue(assy_fixture)
-    _, doc = toCAF(assy, True)
+    doc = toCAF(assy, True)
 
     assert len(get_doc_nodes(doc, True)) == count
 
@@ -659,7 +674,7 @@ def check_nodes(doc, expected):
                     assert pytest.approx(n[k], abs=1e-3) == v
 
     assy = request.getfixturevalue(assy_fixture)
-    _, doc = toCAF(assy, False)
+    doc = toCAF(assy, False)
     check_nodes(doc, expected)
 
 
@@ -807,7 +822,7 @@ def check_nodes(doc, expected, is_STEP=False):
                     assert pytest.approx(n[k], abs=1e-3) == v
 
     assy = request.getfixturevalue(assy_fixture)
-    _, doc = toCAF(assy, True)
+    doc = toCAF(assy, True)
     check_nodes(doc, expected)
 
     # repeat color check again - after STEP export round trip