Camera projection problem.

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manalokos
Licensed Customer
Posts: 441
Joined: Fri Nov 18, 2011 4:43 pm

Hello,

This is a recurrent problem that has affected my work and I bet many of you have the same problem when dealing with meshes that have Camera projected UV's, these are essential when you want to mix CG images with real photographs.

When I render my meshes with camera projected UV's and textures in softimage I have the result I am expecting, but when I switch to octane the textures get completely messed up, specially when the surfaces are more oblique to the camera.

This is an issue that I can partially solve by subdividing the mesh, but even then the final result has distortions, and can make a simple scene become heavy.

Is this a bug in octane? could it be solved by octane team, or am I doing something wrong?
I attached an example to show you what I mean!

Best regards
Filipe
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camera-projection-problem.jpg
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convergen
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Joined: Mon Mar 28, 2011 1:57 am
Location: Adelaide, Australia

try triangulating your mesh before projecting the UV's onto it?
Convergen | Adelaide Australia
Windows 7 x64 | GTX 580 1.5GB | 12GB DDR3 | Core i7 920 @ 3.6ghz
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manalokos
Licensed Customer
Posts: 441
Joined: Fri Nov 18, 2011 4:43 pm

I just tried triangulating the mesh before applying the UV's, but the problem persists...
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face
Octane Plugin Developer
Posts: 3204
Joined: Sat Mar 06, 2010 2:10 pm
Location: Germany

Modo has the same problem, not so extreme but it was there...
Workaround would be to render out a material id with the info kernel and compose it later...

face
Win10 Pro, Driver 378.78, Softimage 2015SP2 & Octane 3.05 RC1,
64GB Ram, i7-6950X, GTX1080TI 11GB
http://vimeo.com/user2509578
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manalokos
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Posts: 441
Joined: Fri Nov 18, 2011 4:43 pm

Hello Face,


Do you think the problem is caused by Softimage, or is it Octane?
It must be something about the way octane and softimage interpolate the UV's...

Yes, I usually composite with material ID, but it would be great not having to do it,
also reflections and other secondary bounces will be affected by the distortion...

Best regards
Filipe
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face
Octane Plugin Developer
Posts: 3204
Joined: Sat Mar 06, 2010 2:10 pm
Location: Germany

The problem is caused by Octane.
Modo has the same problem when i create a plane and use a camera projection.

face
Win10 Pro, Driver 378.78, Softimage 2015SP2 & Octane 3.05 RC1,
64GB Ram, i7-6950X, GTX1080TI 11GB
http://vimeo.com/user2509578
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manalokos
Licensed Customer
Posts: 441
Joined: Fri Nov 18, 2011 4:43 pm

does the Octane team know about this problem? it is an important issue to fix!

Regards
Filipe
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face
Octane Plugin Developer
Posts: 3204
Joined: Sat Mar 06, 2010 2:10 pm
Location: Germany

I don´t know...

face
Win10 Pro, Driver 378.78, Softimage 2015SP2 & Octane 3.05 RC1,
64GB Ram, i7-6950X, GTX1080TI 11GB
http://vimeo.com/user2509578
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manalokos
Licensed Customer
Posts: 441
Joined: Fri Nov 18, 2011 4:43 pm

Well, I hope they read this thread! ;)
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roeland
OctaneRender Team
Posts: 1822
Joined: Wed Mar 09, 2011 10:09 pm

Octane doesn't support this at the moment. UV coordinates of a point are found by linear interpolation between the UV coordinates of the vertices. The projection of the texture to the quad is a projective transform, it needs a kind of non-linear interpolation. I can put this feature on our the TODO list.

--
Roeland
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