Issue with URDF file import to isaac sim 5.0.0

Omniverse Isaac Sim
1

Isaac Sim Version

[*] Other (please specify): 5.0.0

Operating System

Ubuntu 22.04
Ubuntu 20.04
Windows 11
Windows 10
[*] Other (please specify): Ubuntu 24.04

GPU Information

  • Model: RTX 4060 8 GB vRAM
  • Driver Version: 570.169

Topic Description

Detailed Description

I have been trying to import a URDF file of UR5 robot from the official site: universal_robot/ur5_moveit_config at kinetic-devel · ros-industrial/universal_robot · GitHub

As an MSc Robotics student, I am trying to complete the fundamental workflow of importing a standard UR5 robot URDF into Isaac Sim 5.0.0 to control it with ROS 2. I have been following standard procedures, but the robot consistently imports as a static 3D model with disabled or missing physics joints, making it uncontrollable. This prevents me from proceeding with my project work.

Steps to Reproduce

  1. Downloaded the robot description files from the official Universal Robots repository.
  2. Attempted to convert the .xacro file to a .urdf file using the xacro command-line tool. This process was difficult and failed with “Undefined substitution argument” errors unless multiple specific arguments (e.g., ur_type, use_fake_hardware) were provided.
  3. In a new Isaac Sim scene, went to File > Import > URDF.
  4. Selected the generated ur5.urdf file.
  5. In the URDF Importer options, I enabled Fix Base and Create Physics Scene.
  6. Clicked Import.

Actual Results

The robot model appears in the scene, but it is not a controllable articulation. In the Stage panel, the joints prim is greyed out with a disabled symbol (🚫). The robot cannot be controlled via Python scripting or OmniGraph because no physics joints are present.

Expected Results

The robot should import as a fully functional Articulation, with active PhysicsRevoluteJoint prims in the Stage hierarchy. It should be controllable, and its joints should be able to hold their position against gravity after adding an Articulation component and setting stiffness properties.

Error Messages

From MoveIt Setup Assistant when loading the URDF

Error: Virtual joint does not attach to a link on the robot (link ‘’ is not known)

Also from MoveIt Setup Assistant

terminate called after throwing an instance of ‘ament_index_cpp::PackageNotFoundError’
what(): package ‘robot_description’ not found

Additional Information

What I’ve Tried

  1. Attempted to re-import the URDF multiple times with different settings.
  2. Tried to manually add an Articulation component to the imported model, but this fails as no physics joints exist on the imported prim.
  3. Attempted to use the built-in Isaac Sim asset for the UR5 (Create > Isaac > Robots > UR5). This also resulted in an object without controllable joints.
  4. Verified that my ROS 2 environment and MoveIt2 installations are correct.
  5. Performed a full, clean re-installation of my NVIDIA drivers and Isaac Sim as recommended for fixing potential corruption, but the import issue persists.

Additional Context

The issue seems to be a fundamental problem with how physics objects are being handled in Isaac Sim 5.0.0. Even the most basic primitives do not work as expected. For example, using the Create > Mesh > Cube menu item generates a generic Mesh primitive, not a parametric Cube primitive with an editable size property. This behavior is inconsistent with tutorials and documentation from previous versions and makes it impossible to follow basic robotics workflows.

2

Please check if Tutorial 6: Setup a Manipulator — Isaac Sim Documentation is helpful.

3

Hello!

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