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Re: 3d device coordinates from a 3D polyline.... [message #81504 is a reply to message #81502]

Mon, 01 October 2012 05:31

David Fanning
Messages: 11724
Registered: August 2001

Senior Member

George.millward@yahoo.com writes:

> I have am idlgrpolyline which I can rotate in a 3D view (with the trackball).
> I want to know the 2D coordinates of this line in the device (ie,the 2D the projection in the window). Can't figure it out.

I'm no expert in this area, but I think the 3D to 2D
conversions of the transformation matrix (which you
can recover from the trackball) are well known. You
can read the answer at the bottom of this article,
for example:

http://math.stackexchange.com/questions/336/why-are-3d-
transformation-matrices-4x4-instead-of-3x3

Cheers,

David

--
David Fanning, Ph.D.
Fanning Software Consulting, Inc.
Coyote's Guide to IDL Programming: http://www.idlcoyote.com/
Sepore ma de ni thui. ("Perhaps thou speakest truth.")

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[Message index]

		Re: 3d device coordinates from a 3D polyline.... By: DavidF[1] on Mon, 01 October 2012 10:10
		Re: 3d device coordinates from a 3D polyline.... By: George.millward on Mon, 01 October 2012 10:07
		Re: 3d device coordinates from a 3D polyline.... By: David Fanning on Mon, 01 October 2012 05:31
		Re: 3d device coordinates from a 3D polyline.... By: George.millward on Fri, 28 September 2012 14:31
		Re: 3d device coordinates from a 3D polyline.... By: lecacheux.alain on Tue, 02 October 2012 02:22

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