title: "Distance" (or angular magnitude) between two quaternions?
body: <p>I want to find the "distance" between two quaternions. By "distance" I mean a single float or int, not another quaternion (that would be the difference, i.e. <code>inverse(q1)*q2</code>). I guess you could call what I want "angular magnitude".</p>
  
  <p>I need to apply more torque to a physics object the further it's rotated from its original angle.</p>
  
  <p>I don't understand the maths involved in quaternions, so a code-based example would be most helpful. I've looked at several other questions but I don't believe any answer my question, or at least not in a way I understand it.</p>