Simulation speed Orbit RL Environment

Hello, I am training a quadruped in Isaac Orbit. Playing the trained policy gives the following results:


All three videos display the same trained policy but with different values for the “decimation”. The policy was trained using a simulation_dt of 120 Hz and decimation of 1. To my knowledge, the decimation only determines the amount of simulation steps per environment step. I understand that changing the decimation value will result in different behaviour of the robot as it was not trained with this value.

But why does the decimation value also influence the ‘speed’ of the simulation. For a small decimation value it seems like the robot is jumping in slow motion with low gravity. If I increase the decimation value to an even higher value than shown in the video (>4) the simulation runs above real-time speed. Is there a way to fixate the speed of the simulation (The speed at which it is displaying) such that the robot jumps with the same speed it would in real life (independent of what decimation value I chose)?