i feel like this is a simple question, but nevertheless I got stuck somehow. I have a bunch of bodies connected with joints. What I need to do is, I want to build the transformation matrix for body A in respect to body B. As far as I know, ODE only returns rotation and position in the *global* reference frame. So it's easy to get the global orientation of A and B. But what do I need to do to get the 'relative' orientation of A in respect to B?
If I take the three transformation matricies T(G<A) (should mean, transformation from A to Global) , T(G<B) and T(A<B) if found out that:
T(G<B) = T(G<A) T(A<B) (from: http://www.kwon3d.com/theory/transform/transform.html
Is it correct to compute T(A<B) as:
T(A<B) = T(G<A)^-1 T(G<B)
Are there other ways to find out the relative orientation of two bodies ?
Any help would be very much appreciated,