Approximating physics calculations for custom imported robot

I’ve successfully imported a custom robot to Isaac Sim via URDF. The physics seem to be working properly, but the calculations are very slow. Is there any way to introduce approximations of the robot as a box (instead of a collection of complex components) to speed up the simulation?

Hi,
I would be a bit surprised if the bottleneck would be the more complex collision approximations. You can eventually replace them by box approximation by selecting those and changing the approximation type. However first I would recommend you to enable omni.physx.fabric extension to speedup the results write. This would skip the USD update and write to Fabric.
If you enable the profiler extension and press F7 you should be able to see where the time goes, you will have increase the CPU depth for the profile zones.
Or feel free to send me the USD file through a private message I can take a look what could be improved and suggest improvements.
Regards,
Ales

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Is there a way to enable the omni.physx.fabric extension from the Python API? I’m already importing physx with omni.physx.acquire_physx_interface(), but I haven’t been able to find much documentation on using it to enable/disable extensions via code.

@AlesBorovicka
I can not find physx.fabric extension in isaac sim 2022.2.1 as follow:

How to enable it?

Yes, thats possible using the extension manager from python:

manager = omni.kit.app.get_app().get_extension_manager()
manager.set_extension_enabled_immediate("omni.physx.fabric", True)

Ales

Ah sorry you are using IsaacSim that is using a bit older version of kit (104.2) where this extension was called omni.physx.flatcache. This got rebranded in 105.0 to Fabric (Flatcache → Fabric).

Ales

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