At 12:56 PM 9/16/2008, you wrote:

I have 4 2D points in (computer) screen-space, and I need to reverse-project them back into 3D space. ...

http://library.wolfram.com/infocenter/Articles/2794/ http://campar.in.tum.de/Students/SepPoseEstimation http://opencvlibrary.sourceforge.net/Posit will sorta work, but it can diverge or loop. thanks --- vice-chair http://ocjug.org/