[Isaac Sim 6.0.1] Newton Engine Cable (Cosserat Rod) Example (cable_twist) Support & How to Convert PhysX USD to Newton

Omniverse Isaac Sim
1

Important: Isaac Sim support

Note: For Isaac Sim support, the community is gradually transitioning from this forum to the Isaac Sim GitHub repository so that questions and issues can be tracked, searched, and resolved more efficiently in one place. Whenever possible, please create a GitHub Discussion or Issue there instead of starting a new forum topic.

Note: For any Isaac Lab topics, please submit your topic to its GitHub repo ( GitHub - isaac-sim/IsaacLab: Unified framework for robot learning built on NVIDIA Isaac Sim · GitHub ) following the instructions provided on Isaac Lab’s Contributing Guidelines ( Contribution Guidelines — Isaac Lab Documentation ).

Please provide all relevant details below before submitting your post. This will help the community provide more accurate and timely assistance. After submitting, you can check the appropriate boxes. Remember, you can always edit your post later to include additional information if needed.

Isaac Sim Version

6.0.1
6.0.0
5.1.0
5.0.0
4.5.0
4.2.0
4.1.0
4.0.0
4.5.0
2023.1.1
2023.1.0-hotfix.1
Other (please specify):

Operating System

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

GPU Information

  • Model: RTX A4000
  • Driver Version: 573.06

Topic Description

Detailed Description

Hello, I have two questions regarding the newly introduced Newton physics backend in Isaac Sim 6.0.1.

Question 1. Is it possible to reproduce Newton’s cable (Cosserat rod) example in Isaac Sim?

The Newton repository ( GitHub - newton-physics/newton: An open-source, GPU-accelerated physics simulation engine built upon NVIDIA Warp, specifically targeting roboticists and simulation researchers. · GitHub ) includes a cable_twist example that can be run with the following command:

python -m newton.examples cable_twist

This example simulates twist propagation along a Cosserat rod (cable). I would like to know whether it is currently possible to reproduce the same cable/rod simulation using the Newton backend inside Isaac Sim 6.0.1.

Based on my own research of the official documentation ( Newton Physics Backend — Isaac Sim Documentation ), it appears that the Newton backend in Isaac Sim 6.0.1 currently only supports rigid bodies, articulations, joints, and basic collision shapes, and that deformable bodies / cables / rods are not yet supported. Could you please confirm whether this understanding is correct?

Question 1-1. If this is not currently supported, when is it expected to be supported?

If there is a roadmap or an approximate timeline (e.g., a specific upcoming release), could you please share it?

Question 2. How can I convert an existing PhysX-based USD scene (rigid body, articulation, joint, collision) to run on the Newton engine?

I would like to know if there is an official method or guide for converting a USD scene that is currently set up for PhysX (including rigid bodies, articulations, joints, and collisions) so that it can run on the Newton engine, either as-is or with minimal modification.

Specifically:

  • Is there a dedicated converter script/tool available?
  • Which USD schema attributes need to be manually adjusted (e.g., joint body0/body1 parent-child relationships, ArticulationRootAPI, etc.)?
  • Is there a supported conversion workflow available via the Isaac Sim UI or Python API?

Steps to Reproduce

  1. (N/A)

(Add more steps as needed)

Error Messages

(If applicable, copy and paste any error messages you received)

(N/A)

Screenshots or Videos

(If applicable, add screenshots or links to videos that demonstrate the issue)

(N/A)

Additional Information

What I’ve Tried

(Describe any troubleshooting steps you’ve already taken)

  1. Reviewed the Newton GitHub repository and the cable_twist example source code.
  2. Reviewed the official Isaac Sim 6.0.1 documentation (Newton Physics Backend page) to understand the current scope of support and known limitations.

Related Issues

(If you’re aware of any related issues or forum posts, please link them here)

Additional Context

(Add any other context about the problem here)

  1. I understand the Newton backend in Isaac Sim 6.0.1 is still in an “Experimental” stage.
  2. I am asking this because cable/rod simulation is needed for upcoming robot manipulation / soft robotics research work.
3

Hi, Thank you for your detailed questions about Newton physics support in Isaac Sim 6.0.1. Let me address each of your questions:

Question 1: Cable/Cosserat Rod Support

You’re correct in your understanding. As of Isaac Sim 6.0.1, the Newton backend currently supports:

  • Rigid bodies
  • Articulations
  • Joints
  • Basic collision shapes

Deformable bodies, cables, and Cosserat rods are not yet supported in the Isaac Sim integration of Newton. While these features exist in the standalone Newton repository (as you’ve seen with the cable_twist example), they haven’t been integrated into Isaac Sim yet.

Question 1-1: Timeline for Support

I don’t have specific timeline information to share regarding when deformable body/cable support will be added to Isaac Sim’s Newton backend. Since this is marked as an experimental feature in 6.0.1, please keep an eye on future Isaac Sim release notes for updates on new Newton features being integrated.

Question 2: PhysX to Newton Conversion

Currently, there isn’t an automated converter tool for migrating PhysX USD scenes to Newton. The conversion process requires manual adjustments to USD schemas and attributes. Please check the Asset Compatibility in the doc.

For your research needs with cable/rod simulation, I’d recommend either:

  1. Using the standalone Newton Python package directly (outside Isaac Sim) for now
  2. Monitoring the Isaac Sim 6.x release notes for Newton feature updates
  3. Consider PhysX deformable bodies as an interim solution if they meet your requirements and if you need to run your simulation in Isaac Sim.

Hope this helps. Let us know if you have other questions.