IsaacGym returns "nan" values from self.rigid_body_states for some of my asset links

Hi there!

I’m making a custom IsaacGym environment, which requires two assets. For one of my assets the IsaacGym fails to calculate several of its body states (position, orientation, etc). It calculates correctly only the root link, and for all the rest it calculates nan values. Can anyone help me solve this problem? URDF file is ok, I check it with several utils.

Ok, I found what the problem was. I had to install IsaacGym to my personal PC for the visualization, and it turns out that the URDF file was faulty (every joint should have a “velocity” parameter greater than zero, and one of them was zero). It’s not a problem for some other simulators and visualizers, but it is for IsaacGym. I exported this URDF from USD file with IsaacSim’s USD to URDF exporter, but IsaacGym rejected it. Be careful with URDF files, ppl.