Mujoco 'kp', 'gear', 'stiffness', and 'damping' vs IsaacGym 'stiffness' and 'damping'

Could someone please help clarify a doubt? :)

I am calibrating an IsaacGym simulation on real robot trajectories, and I am finding considerable mismatch between the dynamics of a calibrated Mujoco model vs the dynamics of the same model in IsaacGym.

In particular:

  1. I am not sure whether IsaacGym’s ‘stiffness’ and ‘damping’ parameters correspond to Mujoco’s ones?

  2. Also, changing Mujoco’s ‘kp’ and ‘gear’ properties (for position actuators) does affect the dynamics in IsaacGym, but I cannot find any reference to them in the joints properties or in the documentation, so I am not sure how they are being used in the simulation. Ideas? :)