yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

I was about to send questions about this a few days ago.
Do you mean one-side multiplication returns the same result as two-side 
for normalized quaternions? Did you check that?
Can we consider quaternions are always normalized?
I'm never really sure when it comes to quaternions, but I would have 
write the same operation than Boon.


Bruno

> 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.
>
>   


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