fix stem modification and remove string conversion

example/position_retargeting/hand_robot_viewer.py

@@ -64,9 +64,9 @@ def __init__(self, robot_names: List[RobotName], hand_type: HandType, headless=F
             # Build robot
             urdf_path = Path(config.urdf_path)
             if "glb" not in urdf_path.stem:
-                urdf_path = str(urdf_path).replace(".urdf", "_glb.urdf")
+                urdf_path = urdf_path.with_stem(urdf_path.stem + "_glb")
             robot_urdf = urdf.URDF.load(str(urdf_path), add_dummy_free_joints=True, build_scene_graph=False)
-            urdf_name = urdf_path.split("/")[-1]
+            urdf_name = urdf_path.name
             temp_dir = tempfile.mkdtemp(prefix="dex_retargeting-")
             temp_path = f"{temp_dir}/{urdf_name}"
             robot_urdf.write_xml_file(temp_path)