title: Can I use slerp multiple times to average quaternions?
body: <p>As I understand slerp interpolates between two quaternions and returns an unit quaternion. So if I want to average 3 quaternions could I do(Assuming they all are close to each other):</p>
  
  <pre><code>Eigen::Quaterniond t4;
  Eigen::Quaterniond u4;
  Eigen::Quaterniond v4;
  Eigen::Quaterniond average1 = t4.slerp(0.5, u4);
  Eigen::Quaterniond average2 = average1.slerp(0.5, v4);
  </code></pre>
  
  <p>Intuitively it makes sense to me, but then again its quaternions we're talking about.</p>