[Bug Report] Contact penetration

[elle-miller]

I am simulating a franka arm with a custom-made object. I am using convex decomposition for the object's colliders, which is visualised in the video.

I would like to improve the contact collision behaviour, many times throughout the video the gripper fingers penetrate the sides of the object, and it becomes "stuck" there.

In addition, I am using custom contact sensors on the gripper fingers. When I try and filter the contacts to only measure the object's forces, I receive the following message GPU Contact filter for collider is not supported for object ..... I had this working fine for default objects, so seems it is related to the convex decomposition.

Let me know what options I have for improving this behaviour. Thank you! :)

PGT_open_broken-2025-01-17_09.34.14.mp4

System Info

Describe the characteristic of your environment:

• Commit: Isaac Lab 1.2.0
• Isaac Sim Version: 4.2.0
• OS: Ubuntu 20.04
• GPU: RTX 2080
• CUDA: 12.2
• GPU Driver: 535.183.01

Checklist

• I have checked that there is no similar issue in the repo (required)
• I have checked that the issue is not in running Isaac Sim itself and is related to the repo

Acceptance Criteria

• Have the robot pick up the object without visibly penetrating the sides

[RandomOakForest]

Thank you for posting this. It may be a limitation in the PhysX extension, we are reviewing this issue.

[elle-miller]

Thank you @RandomOakForest, looking forward to your comments

[RandomOakForest]

After discussing with the team, here are a few suggestions. We think the sides of the cube-like object are a bit thin, maybe it would help making them thicker. Also, convex decomposition may not be as good as an SDF mesh in this case. Finally, try decreasing the simulation dt (time between steps) while increasing the position and velocity iterations.

Thanks for your interest in Isaac Lab. Regarding this post, we think is not precisely something we identify as a bug just yet, so I will move it to our Discussions section.