Just a minor thing and maybe I am not right with that. I find the descritpions of mju_negPose and mju_neg_quat somewhat misleading or at least not free of potential misinterpretation. mju_neg_quat: I assume thats the inverse of the quaternion and not -q? mju_neg_pose: Could be the inverse of the transform or simply translation and rotation reversed ? Please consider updating that information. Kind regards!