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how to define arbitrary point coordinates?


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Hi, is there a way to define in VOPs your own coordinate space for point? Say I would like to state local point coordinates where z is point normal, x is a tangent to zet and y is a cross product of former two. How can I do that? I need it as a sop op, to describe the motion in local point coordinates but not in world coordinates.

Thanks

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Hi zveris,

Check out the spaceCreate and spaceFrame VOPs in the Axyz Bundle (Codex>Tools>Vex).

One of these should work for you.

They both build an orthonormal basis, given a point and a "lookat" vector. spaceCreate() also returns transform matrices for points, vectors, and normals, and the Euler angles extracted from the rotation matrix.

See the included demo hip file, which uses these VOPs in the SOP context, for sample usage.

Cheers!

NOTE: the file is tarred and gzipped (has extension .tgz ) so make sure your browser downloads it correctly... some people have had some problems with IE...

EDIT: I just saw the long thread in the SESI forum... and if Edward's interpretation is right, then I agree: maybe you shouldn't be going about it using local frames...

This double-posting can get a little confusing :rolleyes:

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