Hi Lucie, What you're looking for is how to convert the quaternion representation of a rotation into the Euler angle representation. Take a look at http://en.wikipedia.org/wiki/Conversion_between_quaternions_and_Euler_angles for more info and the equations.
Alternatively, you can get the rotation about an arbitrary axis this way: 1) Create a unit vector perpendicular to your axis (e.g. (0,1,0) for rotations about the z-axis) 2) Rotate this vector by the quat: rotated = quat * forward_vec * quat.conj() 3) Project the result onto the plane perpendicular to your axis (see http://www.euclideanspace.com/maths/geometry/elements/plane/lineOnPlane/index.htm for info on projecting vectors onto planes) 4) Normalize the result to unit length. 5) Take the dot product between your initial forward vector and this normalized rotated forward vector. 6) Take the inverse cosine to get the angle. Cheers, Tom ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=35869#35869 _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
