yade-dev team mailing list archive

[Václav Šmilauer <eudoxos@xxxxxxxx>]

> Can someone advise me how do I multiply a  Quaternion.Conjugate *
> Vector * Quaternion?  The following doesn't work, including the
> assignment in terms of "=" and "()".  I looked at the wm3 template,
> but suspect that vector*quaternion is not supported?
What are you trying to achieve in terms of rotations? If you just try to
convert the point from global to local coordinates, use

localPt=state->ori.Conjugate()*(pt-state.pos)

>     localP1 = state1.ori.Conjugate() * tempP1 * state1.ori;

I think mathematitians write this multiplication from both sides, but
they really mean just rotation by the inverse (=conjugate, for
normalized) quaternion.

v