public MuscleHandle(HumanPartDoF partDoF, HeadDoF headDoF)
        {
            if (partDoF != HumanPartDoF.Head)
            {
                throw new InvalidOperationException("Invalid HumanPartDoF for head, please use HumanPartDoF.Head");
            }

            humanPartDoF = HumanPartDoF.Head;
            dof          = (int)headDoF;
        }
 public MuscleHandle(HeadDoF headDoF)
 {
     humanPartDoF = HumanPartDoF.Head;
     dof          = (int)headDoF;
 }