I have global rotations for an object, how do I convert to local rotations?

I am using data from the Kinect inside a Unity game. I want to move a model by transforming the joints. The problem is, the Kinect gives global rotations and I need local rotations to move the model.

I’m not that familiar with 3D maths - does anyone have an example of taking a global quaternion (xyzw) and converting it to a local quaternion?

Thanks in advance for any pointers!

This guy posted an interesting answer to your problem:

http://forum.unity3d.com/threads/find-local-rotation-given-global-rotation.136379/

Not perfect, but working.