URDF Import Error

Omniverse Isaac Sim
,
1

Hello,

I am trying to import ‘lite6’ URDF file in one of example file ‘hello_world.py’. The URDF import example I’m using is from 4.5.0 URDF example. This file works with ‘panda arm’. However, when I try .urdf file, it has following errors:

2025-06-11 16:55:45  [Error] [isaacsim.asset.importer.urdf] *** Failed to load '/home/user/xarm_ws/src/xarm_ros2/xarm_description/urdf/lite6.urdf'
2025-06-11 16:55:45  [Error] [isaacsim.asset.importer.urdf] Failed to parse URDF file 'lite6.urdf'

Manually importing the same URDF via the USD File→Import menu succeeds without issue. Here’s the relevant portion of my scene setup:

def setup_scene(self):

        world = self.get_world()
        world.scene.add_default_ground_plane()

        # Acquire the URDF extension interface for parsing and importing URDF files
        urdf_interface = _urdf.acquire_urdf_interface()

        # Configure the settings for importing the URDF file
        import_config = _urdf.ImportConfig()
        import_config.convex_decomp = False  # Disable convex decomposition for simplicity
        import_config.fix_base = True       # Fix the base of the robot to the ground
        import_config.make_default_prim = True  # Make the robot the default prim in the scene
        import_config.self_collision = False  # Disable self-collision for performance
        import_config.distance_scale = 1     # Set distance scale for the robot
        import_config.density = 0.0          # Set density to 0 (use default values)

        # Retrieve the path of the URDF file from the extension
        extension_path = get_extension_path_from_name("isaacsim.asset.importer.urdf")
        # root_path = extension_path + "/data/urdf/robots/franka_description/robots"
        root_path = '/home/user/xarm_ws/src/xarm_ros2/xarm_description/urdf'
        # file_name = "panda_arm_hand.urdf"
        file_name = 'lite6.urdf'

        # Parse the robot's URDF file to generate a robot model
        result, robot_model = omni.kit.commands.execute(
            "URDFParseFile",
            urdf_path="{}/{}".format(root_path, file_name),
            import_config=import_config
        )

         # Update the joint drive parameters for better stiffness and damping
        for joint in robot_model.joints:
            robot_model.joints[joint].drive.strength = 1047.19751  # High stiffness value
            robot_model.joints[joint].drive.damping = 52.35988    # Moderate damping value

        # Import the robot onto the current stage and retrieve its prim path
        result, prim_path = omni.kit.commands.execute(
            "URDFImportRobot",
            urdf_robot=robot_model,
            import_config=import_config,
        )

        # Initialize a predefined task for the robot (e.g., following a target)
        my_task = FollowTarget(
            name="follow_target_task",
            franka_prim_path=prim_path,  # Path to the robot's prim in the scene
            franka_robot_name="fancy_franka",  # Name for the robot instance
            target_name="target"  # Name of the target object the robot should follow
        )

        # Add the task to the simulation world
        world.add_task(my_task)

        return

Any assistance on this problem will be helpful.

Thank you.

2

Is this file path correct?

3

Hello!

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