warp.quat\_twist
================

.. function:: warp._src.lang.quat_twist(axis: vec3f, q: quatf) -> quatf

   .. hlist::
      :columns: 8

      * Kernel
      * Differentiable

   Extract the twist quaternion of ``q`` around ``axis``.
   
   This performs a swing-twist decomposition and returns the component of
   rotation in ``q`` whose rotation axis is parallel to ``axis``.
   
   :param axis: Twist axis (expected to be normalized).
   :param q: Input quaternion in ``(x, y, z, w)`` layout.
   
   :returns: Unit twist quaternion.
   :rtype: wp.quat