adding support for unnamed geoms

python/mujoco/usd/demo.py

@@ -6,7 +6,7 @@ import exporter
 if __name__ == "__main__":
 
   # load a model to mujoco
-  m = mujoco.MjModel.from_xml_path("/Users/abhishek/Documents/research/mujoco/model/humanoid/humanoid.xml")
+  m = mujoco.MjModel.from_xml_path("/Users/abhishek/Documents/research/mujoco/test/engine/testdata/catenary.xml")
   d = mujoco.MjData(m)
 
   # create an instance of the USDExporter

python/mujoco/usd/exporter.py

@@ -235,6 +235,9 @@ class USDExporter:
   def _load_geom(self, geom: mujoco.MjvGeom):
 
     geom_name = mujoco.mj_id2name(self.model, geom.objtype, geom.objid)
+    if not geom_name:
+      geom_name = f"unnamed_geom{geom.objid}"
+
     assert geom_name not in self.geom_name2usd
 
     texture_file = self.texture_files[geom.texid] if geom.texid != -1 else None
@@ -250,13 +253,11 @@ class USDExporter:
           texture_file=texture_file,
       )
     else:
-
       mesh_config = shapes_module.mesh_config_generator(
           name=geom_name,
           geom_type=geom.type,
           size=geom.size   
       )
-
       usd_geom = component_module.USDPrimitiveMesh(
           mesh_config=mesh_config,
           stage=self.stage,
@@ -276,6 +277,8 @@ class USDExporter:
     for i in range(self.scene.ngeom):
       geom = self.scene.geoms[i]
       geom_name = mujoco.mj_id2name(self.model, geom.objtype, geom.objid)
+      if not geom_name:
+        geom_name = f"unnamed_geom{geom.objid}"
 
       if geom_name not in self.geom_name2usd:
         self._load_geom(geom)