Fix 3mf export on scenes with multiple nodes with same geometry (#2473)

mikedh · web-flow · commit 341b0ceea875 · 2025-10-21T14:35:02.000-04:00
- Change 3mf file used on round trip test to cover the case
- Fixed by getting model id of the geometry instead of the node, if
available
diff --git a/models/pyramids.3mf b/models/pyramids.3mf
diff --git a/tests/test_3mf.py b/tests/test_3mf.py
@@ -57,8 +57,8 @@ def test_roundtrip(self):
 
         # test a scene round-tripped through the
         # 3MF exporter and importer
-        s = g.get_mesh("cycloidal.3DXML")
-        assert len(s.geometry) == 13
+        s = g.get_mesh("pyramids.3mf")
+        assert len(s.geometry) == 6
 
         # export and reload
         r = g.trimesh.load(
diff --git a/trimesh/exchange/threemf.py b/trimesh/exchange/threemf.py
@@ -420,7 +420,7 @@ def model_id(x):
                             etree.Element(
                                 "item",
                                 {
-                                    "objectid": model_id(node),
+                                    "objectid": model_id(data.get('geometry', node)),
                                     "transform": transform,
                                     uuid_tag: str(uuid.uuid4()),
                                 },

Original file line number	Diff line number	Diff line change
`@@ -420,7 +420,7 @@ def model_id(x):`
`420`	`420`	`etree.Element(`
`421`	`421`	`"item",`
`422`	`422`	`{`
`423`		`- "objectid": model_id(node),`
	`423`	`+ "objectid": model_id(data.get('geometry', node)),`
`424`	`424`	`"transform": transform,`
`425`	`425`	`uuid_tag: str(uuid.uuid4()),`
`426`	`426`	`},`