So if you want it in real world units instead of pixels then it should be mm to inches. So multiply it by 25.4. Also you should do 2/haperture to get the offset in distance instead of pixels.
-1*((2/haperture)*(offset*25.4)) -deke On Fri, May 6, 2011 at 07:19, John RA Benson <[email protected]>wrote: > 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]> >> <[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 >> [email protected]http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-python >> >> _______________________________________________ >> Nuke-python mailing >> [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://forums.thefoundry.co.uk/ > http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-python > >
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