Re: axis of rotation :: again

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Angus MacDonald Dorbie (dorbie++at++multipass.asd.sgi.com)
Thu, 15 May 1997 14:14:44 -0700


SetTrans will explicitly set the translation of the matrix, not
multiply it by the translation so this is not what you want to do.

Look at pfMatrix for the calls you want.

Cheers,Angus.

On Apr 20, 8:32am, Garrett Williams wrote:
> Subject: Re: axis of rotation :: again
> Angus MacDonald Dorbie wrote:
> >
> > translate by (-x, -y, -z)
> > perform the rotation then
> > translate by (+x, +y, +z)
> >
> > On Apr 19, 4:29pm, Garrett Williams wrote:
> > > Subject: axis of rotation :: again
> > > Well I gess I was not too clear:
> > >
> > > I tryed Scott's idea with no result and Angus wants more info..
> > >
> > > I have a model with multiple parts which I wish to rotate (say legs and
> > > arms) I am able to rotate each part alone but they all rotate about the
> > > same point (0,0,0) of the model. What I wish to do is move this point
> > > of rotation to another location like the hips or shorlders.
> > >
> > > I hope this is more clear... Thanks for the help....
> > >
> > >
> > > garrett
> > >
>
> I spent some time trying to do that yesterday with no results..
>
> I see the proublem this way..::
>
> The model has a axis (0,0,0) which is diferent from the world axis.
> When the model is moved the axis is also moved the same amount so the
> rotation is about the same point just moved.
>
> ("loop step"){
> mv_l_leg->setRot(0, 10*step, 0.0f);
> mv_r_leg->setTrans( -0.40f, 0.10f, 0.30f);
> mv_r_leg->setRot(0, -(10*step), 0.0f);
> mv_r_leg->setTrans( 0.0f, 0.0f, 0.0f);
> }
>
> this has no effect both leggs rotate about the same point..
>
> Thanks ::: garrett
>-- End of excerpt from Garrett Williams

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