Ah, got to get my hands on that c44matrix so that I can see the result. Is Ivan still in the mailing list? Any chance to compile a new one? Or is the source code somewhere? It's an interesting challenge.
On Friday, October 28, 2016, Vincent Langer <m...@vincentlanger.com> wrote: > Hi Erwan, > > ah I did not know about cx and cy - good to know- BUT the whole thing is > for a deep tool and cx and cy do not work in deep expressions. this also > answers the question I am why not using the DepthToPosition node. > > focal length and aperature size is considered by the c44Matrix node in > projection mode. > > cheers, > Vincent > > 2016-10-28 12:33 GMT+02:00 Erwan Leroy <er...@erwanleroy.com > <javascript:_e(%7B%7D,'cvml','er...@erwanleroy.com');>>: > >> Hi >> Maybe you are doing it for the challenge, but is there a reason why you >> would not use the DepthToPosition node built into Nuke? I seems to do >> exactly what you are trying to do (I get a very small error which I believe >> is due to rounding). >> For the fun of it I looked into your expressions, but couldn't go all the >> way through because there is no current build for the C44Matrix for Nuke 9 >> on windows. >> I have 2 things that I believe might be affecting your result (but I >> can't verify): >> >> - I don't see you consider the focal length anywhere? That would have a >> big impact. >> >> - Now this might not apply for every renderer, and Nuke's built in node >> ignores that point as well: In your first expression, you generate a >> "default" position point cloud, with X and Y as planar coordinated, while >> possibly using a "curved" Z_Depth for you Z input. In real world (and Vray >> for exemple) the distance a of a card right in front of a camera would not >> have a single value, as the distance on the sides of the frame would be >> greater than right in front of the camera. >> See attached pictures that illustrate this point. >> >> (Also, for that first expression, why not using cx and cy instead of that >> complex expression) >> >> >> Cheers >> >> *Erwan* LEROY >> www.erwanleroy.com >> >> On Fri, Oct 28, 2016 at 4:04 PM, Vincent Langer <m...@vincentlanger.com >> <javascript:_e(%7B%7D,'cvml','m...@vincentlanger.com');>> wrote: >> >>> Hi there, >>> >>> I am trying to get the math right calculating the worldpositions from z >>> information + camera matrices. >>> >>> my result is close to the rendered position pass - but does not line up >>> perfect. >>> >>> Maybe one of the brains out there can tell me what I am missing/doing >>> wrong >>> >>> This is just a proof of concept for the right math and I use the >>> C44Matrix node from Ivan Busquets. >>> >>> cheers, >>> Vincent >>> >>> -- >>> Vincent Langer >>> Uhlandstr. 29 >>> 71634 Ludwigsburg >>> +49 176 965 177 61 >>> www.vincentlanger.com >>> >>> _______________________________________________ >>> Nuke-python mailing list >>> Nuke-python@support.thefoundry.co.uk >>> <javascript:_e(%7B%7D,'cvml','Nuke-python@support.thefoundry.co.uk');>, >>> http://forums.thefoundry.co.uk/ >>> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-python >>> >>> >> >> _______________________________________________ >> Nuke-python mailing list >> Nuke-python@support.thefoundry.co.uk >> <javascript:_e(%7B%7D,'cvml','Nuke-python@support.thefoundry.co.uk');>, >> http://forums.thefoundry.co.uk/ >> http://support.thefoundry.co.uk/cgi-bin/mailman/listinfo/nuke-python >> >> > > > -- > Vincent Langer > Uhlandstr. 29 > 71634 Ludwigsburg > +49 176 965 177 61 > www.vincentlanger.com > -- *Erwan* LEROY www.erwanleroy.com
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