title: Unity Quaternion - get Euler angles of a component B relative to component A
body: <p>I cannot get my head around Quaternions, and have tried many combination of operators on this (after reading / viewing tutorials). No success - just shows my lack of understanding. Even tried it with angles and atan2() - but all that really showed me was what gimbal lock was. The problem I am trying to solve is:</p>
  
  <p>I have a component (say A, a cube) with some rotation in the world frame of reference (doesn't actually matter what that rotation is, could be orientated any direction).</p>
  
  <p>Then I have another component (say B, another cube) elsewhere in the world space. Doesn't matter what that component's rotation is, either.</p>
  
  <p>What I want to get to in the end are the (Euler) angles of B relative to A, BUT relative to A's frame of reference, not world space. The reason is I want to add forces to A based on B's direction from A, which I can then do with <code>A.rigidbody.addRelativeForce(x, y, z);</code> .</p>
  
  <p>Stuck.</p>