Dose State.qd[3:6] represents the angular velocity in the local body frame?

[hdadong]

Is it correct that in State.qd:

• State.qd[0:3] represents the linear velocity in the world frame, and
• State.qd[3:6] represents the angular velocity in the local body frame?

Are there any document for these?

https://github.com/google/brax/blob/main/brax/generalized/base.py#L71

[btaba]

q and qd are analogous to qpos and qvel in MuJoCo land. If you're referring to a free joint, qvel[0:3] will be the linear velocity and qvel[3:6] will be the angular velocity, and I believe these are both in the world frame.