OK. This functionality will surely depend on the implementation of vect * quat ? In boost::quaternion the quaternion seems to be normalised during the calculation AFAICS. See <libs/math/quaternion/HS03.hpp>. I have to confess that I don't know enough about quaternions to speak with authority. As Janek Kozicki brought up yade http://yade.berlios.de/. My current plan is to look at that as an example useage. Again only for rotations. I'm not even sure yet how I can test the calculations on quaternions. I need to understand more about how they are constructed, starting maybe from an [axis-vector,angle] type maybe, simply because I can visualise that easier than 4 dimensions :-)
An extremely good book on quaternions if you can get it is Quaternions and Rotation Sequences Jack B. Kuipers ISBN 0-691-05872-5 Very recommended and written in one the best styles I've seen for a technical book. hth Martin -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.394 / Virus Database: 268.8.3/362 - Release Date: 12/06/2006