Re: axis of rotation :: again
Garrett Williams (gwilliams++at++etcflorida.com)
Sun, 20 Apr 1997 13:21:56 -0400
Scott McMillan wrote:
>
> >
> > 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....
>
> Lemme try again (and be a little more public). This is what I have done in
> the past with robotic sims where the point of rotation for a particular model
> will always be in the same place with respect to that model. I believe it is
> equivalent to some of the single DCS answers I have seen.
>
> I strive for the following subgraph (for each link in the system), by
> inserting an SCS:
>
> DCS (joint axis - variable)
> |
> SCS (offset to point of rotation - constant)
> |
> Model (Geode,Geosets,etc)
>
> ....later if I want to make it more efficient, I can pfFlatten or ask the 3D
> modelers to give me a new model with the origin moved to the point of
> rotation.
>
> For example if you want the point of rotation to be about 1,1,1 of the models
> coordinate system. The SCS's matrix will consist of a translation of
> -1,-1,-1 (I hope, I dont have that backwards).
>
> I have to align my models so that the single axis of rotation is about the
> z-axis so I generally have to have some rotation in my SCS matrix to align
> this correctly. If I can do it, I will always have the modeller create the
> models with the origin and orientation in the place I need it so that I do
> not have to go through this process.
>
> Hope this helps,
> scott
COOLLLLLLL:: now I have 2 ways that work verry well. I belive that
this way will be faster than the pre and post translate mat...
have a great day to allll..
garrett
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