roundtrip metadata to json

trimesh/exchange/export.py

@@ -145,7 +145,7 @@ def encode(item, dtype=None):
     return export
 
 
-def scene_to_dict(scene, use_base64=False):
+def scene_to_dict(scene, use_base64=False, include_metadata=True):
     """
     Export a Scene object as a dict.
 
@@ -163,12 +163,19 @@ def scene_to_dict(scene, use_base64=False):
     # save some basic data about the scene
     export = {'graph': scene.graph.to_edgelist(),
               'geometry': {},
-              'metadata': scene.metadata.copy(),
               'scene_cache': {'bounds': scene.bounds.tolist(),
                               'extents': scene.extents.tolist(),
                               'centroid': scene.centroid.tolist(),
                               'scale': scene.scale}}
 
+    if include_metadata:
+        try:
+            # jsonify will convert numpy arrays to lists recursively
+            # a little silly round-tripping to json but it is pretty fast
+            export['metadata'] = json.loads(util.jsonify(scene.metadata))
+        except BaseException:
+            log.warning('failed to serialize metadata', exc_info=True)
+
     # encode arrays with base64 or not
     if use_base64:
         file_type = 'dict64'