Armatures in Blender do not work in Isaac sim

Hello,

I have rigged this wheelloader model in blender, the inverse kinematics work fine there. I am then using the alpha blender 4.2 branch to export the armatures to USD however when I do that the armature no longer works. Firstly the inverse kinematics completely dissappears and I dont know how to get that back. Second the body parts no longer move with the bones. I am using the “Bone” parent type in blender to attach parts to bones. Is this behaviour expected? How can I make sure my armatures work in isaac sim? I want to be able to use the replicator to randomize bucket position.

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Isaac Sim Version

4.2.0
4.1.0
4.0.0
2023.1.1
2023.1.0-hotfix.1
Other (please specify):

Isaac Lab Version (if applicable)

1.2
1.1
1.0
Other (please specify):

Operating System

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

GPU Information

  • Model: RTX 4090
  • Driver Version:

Topic Description

Detailed Description

(Describe the issue in detail, including what you were trying to do, what you expected to happen, and what actually happened)

Steps to Reproduce

  1. Create a 4 bar linkage in blender alpha branch 4.2, using armatures. When assigning bones as parents to objects select the “bone” parent type
  2. Export the model as USD with armature option and animation turned on
  3. Open the USD in isaac sim and try to play with the 4 bar linkage
    (Add more steps as needed)

Error Messages

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Screenshots or Videos

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Additional Information

What I’ve Tried

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Related Issues

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Additional Context

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I doubt that the USD exporter supports the kinematics and constraints.

@dkalpay, is this still a problem for you? Can you check if the issue lies in the exported USD file?