[ODE] Naive Pitch/Roll/Yaw rotation questions

[john rieffel]

I'm comfortable using dBodySetRotation and dRFromAxisAndAngle in order
to rotate bodies in the global reference frame, but I'm stumped about
how to rotate objects relative to their own frame of reference.  I'm
sure that it's a simple matter of quaternion arithmetic, but it eludes
me.(kicking myself for never having taken any aero/astro classes, or
graphics classes for that matter).

Imagine, for instance that my body is an airplane - I'd like it be
able to get it to pitch/yaw/roll.  To make things even easier, I only
ever want it to pitch/roll/yaw over a 90 degree angle.   For instance,
if the object's current roll axis is the "z" axis, and its yaw axis is
the "y" axis, then I want a +90 degree yaw to place its roll axis on
the x axis.

thanks,
jr