[BUG]SAPIEN 2.2.2 cannot drive the dexterous hand properly.

[revquiet]

System:

• OS version: [Ubuntu 22.04]
• Python version [Python 3.10.15]
• SAPIEN version (pip freeze | grep sapien): 2.2.2
• Environment: [Desktop]

Describe the bug
When importing a humanoid robot URDF with dexterous hands, the intermediate_joint for both the left and right hands fails to correctly drive or display in SAPIEN 2.2.2. However, the same URDF works as expected in SAPIEN 3.0.0b1. Since SAPIEN 2.2.2 is required for ManiSkill2 compatibility, it is crucial to resolve this issue in the older version for me.

To Reproduce
Steps to reproduce the behavior (use pastebin for code):

1. load the urdf file and the corresponding mesh files.
2. runing the script.
   Expected behavior
   The intermediate_joint for both hands should be correctly driven and displayed, as observed in SAPIEN 3.0.0b1.

Screenshots
If applicable, add screenshots to help explain your problem.
SAPIEN2.2.2:
https://github.com/user-attachments/assets/c8c4e2c7-e305-4374-bc09-c4eaad7bcf9e

SAPIEN3.0.0:
https://github.com/user-attachments/assets/b245b704-9b21-4b33-83c5-d66b7b54da7f

Additional context
Add any other context about the problem here.

[fbxiang]

My guess is that the issue is caused by cylinder collisions, which are not supported in SAPIEN 2 (which converts cylinders to capsules) but supported in SAPIEN 3 (by converting cylinders to meshes with a similar shape). You can verify this by removing all the cylinder collisions and try SAPIEN 2 and 3 again.
My suggestion is to use SAPIEN 3 and ManiSkill3, which include much more feature improvements and bug fixes so you will encounter similar issues a lot less. And we do not plan to support an outdated version.
However, if you have to use SAPIEN 2, you can modify the collision shapes manually to replace the cylinders with meshes, or disable the collisions completely.

[revquiet]

I have already removed all collisions in the URDF, but the issue has not been resolved.

[fbxiang]

The other thing to try is to increase the mass and inertia of all links, and make sure the mass and diagonal of the inertia are at least 1e-6. PhysX is known to skip solving links with small mass properties. SAPIEN 3 does this kind of checking for you but SAPIEN 2 does not.

[revquiet]

Thanks! It makes sense when I increase the mass of the dexterous hands links.