kinda weird, but putting in the cm to inches conversion is close. Glad I'm not working for NASA.
(-1*(2.0/width*offset))/2.54*2 gives me *almost* the value in the file. Close enough, but not exact, due to rounding errors I imagine. this is the left camera, opposite value for the right camera. thanks! JRAB On May 2, 2011, at 6:13 PM, Deke Kincaid wrote: > If your getting an fbx with an existing offset from an app like maya, then > shouldn't you need the offset in distance, not pixels? Maya's filmback > offset is measured in inches. > > -deke > > On Mon, May 2, 2011 at 06:24, John RA Benson <[email protected]> wrote: > width = 1998 > > lens > offset > calculated offset from camera u > (-u/2)*width > calculated u from offset > -1*(2/width*offset > win_translate.u (from camera fbx file) > 20 -24 -18.34 0.024 > 0.01835662 > 23.1 -24 -5.34 0.024 > 0.00534497 > 24 -38 -29.04 0.038 > 0.02906466 > 24 -24 -18.34 0.024 > 0.01835662 > 35 -30 -22.92 0.030 > 0.02294578 > Strange - something funny with our fbx conversions then? Or maybe the > win_translate isn't the filmback offset? > I would have thought the values for offset and calculated offset would be the > same, and the actual win_translate.u and the calculated u would be the same. > the actual offset for the first shot is -24 pixels and the win_translate.u = > 0.18, yet the calculated u is 0.024. > > The 2 cameras with offsets of -24 both had a u of 0.018, but by using these > calculations it should be 0.024. I'm not sure what's correct... > > jrab > > > Deke Kincaid wrote: >> >> u would be: >> -1 * (2/width * offset) >> >> v would be: >> ((root.format.h/root.format.w)*2)/root.format.h * offset >> >> >> -deke >> >> On Thu, Apr 28, 2011 at 14:26, John RA Benson >> <[email protected]> wrote: >> >>> While we're on the subject of cameras and a little matrix math - >>> >>> does anyone have the math for converting pixel values of the offset of a >>> filmback into the window u value for the camera? >>> >>> Say I want to offset the image by 15 pixels, I'd need to adjust the window >>> u by ... ? >>> >>> thanks! >>> JRAB_______________________________________________ >>> Nuke-python mailing list >>> [email protected] >>> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-python >>> >>> >> _______________________________________________ >> Nuke-python mailing list >> [email protected] >> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-python >> >> >> > > _______________________________________________ > Nuke-python mailing list > [email protected] > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-python > > > _______________________________________________ > Nuke-python mailing list > [email protected] > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-python
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