URDF: Automatic Computation of Mass/Inertia

Hi there!

It seems that both masses and inertia tensors can be computed automatically in both Isaac Gym and Sim:


For example in the Isaac Gym assets, both versions are present: In the Franka Panda URDF masses/inertias are not provided, while in many other cases these quantities are explicitly represented.

Two related questions:

  1. Are there any drawback in having masses/inertias computed automatically, e.g. computational effects on the real-time performance?
  2. What would be the motivation for deriving masses/inertias manually and extending the URDF with these?

Thanks in advance!