I know how to use quaternions to rotate my coordinate system about an axis and how to chain those together. Since this is not too complicated I thought it would also be easy to go the other way around, but now my head is smoking and I still couldn't figure out the solution...
Here is my Problem: I have to describe the orientation of a right-handed coordinate system relative to the world coordinate system. The x- and z-axis of this coordinate system are given as vectors (which are orthogonal to each other and normalized).
How can I calculate the quaternion which describes this orientation?