[Question] How do I know what the elements of the obs array are?

[bobakfb]

Question

For instance, in ant.py:_get_obs() I see the observation is built from the qpos and qvel members of some physics object... but I don't understand how to qpos and qvel map that back into the objects in the environment. Through some testing it seems the first 3 elements are the position of the ant's torso, but this might be wrong.

I've tried to follow the logic, but it seems the qvel and qpos initialization is offloaded to dm_control or mujuco, and that sends me further down (assuming dm_control) into loading the xml into some opaque struct. There must be a more straightforward way to do this right? Is this information collected anywhere for the different environments?