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View Full Version : MATHS: Converting a normal and angle to orthonormal basis



cix>foo
02-03-2002, 06:50 AM
I think that's the right terms for it.

I've got a normal, and a rotation about this normal, which I'd like to turn into a 3x3 matrix representing the orthonormal basis which this rotation represents.

Is there a nice easy formula for this kicking about somewhere? It takes me ages to figure this stuff out.

Cas http://www.opengl.org/discussion_boards/ubb/smile.gif

ps. Is there any merit in adding a new Maths forum in OpenGL as these kinds of questions pop up frequently and might be best stashed in a separate archive?

harsman
02-03-2002, 08:04 AM
You could look up glRotate in the spec, it tells you how to create a transform fróm an axis angle pair. Or you could check out this page (http://www.martinb.com/threed/scenegraph/rotations/axis.htm) .

[This message has been edited by harsman (edited 02-03-2002).]

cix>foo
02-03-2002, 05:35 PM
Ooooh, so *that's* what an axis angle is! I did wonder.

Thanks very much for the link; I've already got this code staring right at me in the face in javax.vecmath. Duh.

Cas http://www.opengl.org/discussion_boards/ubb/smile.gif