An [Error] [omni.physicsschema.plugin] occured when importing custom usd file in Issac Sim

[kyuwon416]

No error occurred when importing from isaac-sim, but the following isaac-sim error occurred during the “_design_scene” process before learning with ORBIT, a deep reinforcement learning framework.

2023-10-18 08:49:40 [14,231ms] [Error] [omni.physicsschema.plugin] Rigid Body of (/World/envs/env_0/Valve/base) missing xformstack reset when child of rigid body (/World/envs/env_0/Valve) in hierarchy. Simulation of multiple RigidBodyAPI's in a hierarchy will cause unpredicted results. Please fix the hierarchy or use XformStack reset.
2023-10-18 08:49:40 [14,231ms] [Error] [omni.physicsschema.plugin] Rigid Body of (/World/envs/env_0/Valve/link0) missing xformstack reset when child of rigid body (/World/envs/env_0/Valve) in hierarchy. Simulation of multiple RigidBodyAPI's in a hierarchy will cause unpredicted results. Please fix the hierarchy or use XformStack reset.
2023-10-18 08:49:40 [14,231ms] [Error] [omni.physicsschema.plugin] Rigid Body of (/World/envs/env_0/Valve/valve) missing xformstack reset when child of rigid body (/World/envs/env_0/Valve) in hierarchy. Simulation of multiple RigidBodyAPI's in a hierarchy will cause unpredicted results. Please fix the hierarchy or use XformStack reset.
2023-10-18 08:49:40 [14,250ms] [Error] [omni.physx.plugin] PhysicsUSD: CreateJoint - no bodies defined at body0 and body1, joint prim: /World/envs/env_0/Valve/joints/rootJoint
2023-10-18 08:49:40 [14,250ms] [Error] [omni.physx.plugin] PhysicsUSD: CreateJoint - no bodies defined at body0 and body1, joint prim: /World/envs/env_0/Valve/joints/link0
2023-10-18 08:49:40 [14,250ms] [Error] [omni.physx.plugin] PhysicsUSD: CreateJoint - no bodies defined at body0 and body1, joint prim: /World/envs/env_0/Valve/joints/latch_joint

The custom usd file I want to upload is pictured below.

The prim path is also set as shown in the picture below, and when importing independently from isaac-sim, it loads normally and the simulation works well. But when I run it on ORBIT, the isaac-sim extension throws an error like this, so I’m writing this.

I would really appreciate some help!

[AlesBorovicka]

Hi,
the physics parsing of USD data detected that you are having nested rigid bodies. This will most likely not work as expected, as rigid bodies will try to update the transformation (local transformation is in USD) from simulation world frames. I would resolve the nesting rigid bodies first. The second error about not creating joints is related to the first issue.
Regards,
Ales

[kyuwon416]

Thank you for replying to my question. I looked at the reply and tried to edit it. However, I can’t solve my problem yet. What is the meaning of “nested rigid bodies”?
I looked at the attached image and other contents, and the rigid body has no overlapped(nested) parts.

[AlesBorovicka]

You can see what the problem is in the error message:
Rigid Body of (/World/envs/env_0/Valve/base) missing xformstack reset when child of rigid body (/World/envs/env_0/Valve) in hierarchy. Simulation of multiple RigidBodyAPI’s in a hierarchy will cause unpredicted results. Please fix the hierarchy or use XformStack reset.

Here you have nested rigid bodies, meaning you have in the hierarchy two rigid bodies that move the same hierarchy.
Namely /World/envs/env_0/Valve is a rigid body that moves all the prims below it, while you have also a rigid body on path /World/envs/env_0/Valve/base which is a child of the Valve, meaning that movement of the Valve - change of transform also changes the transformation of the base. While base suppose to move freely as it was defined as a rigid body. This nesting of rigid bodies wont work.
Regards,
Ales