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Rendering vertex color / zbrush polypaint
Posted: Fri Mar 29, 2013 6:37 pm
by markflorquin
I'm trying to render fibers without texture. (Zbrush Fibermesh).
Color information is stored in the OBJ file (I can see it in Meshlab for example). I wonder however if it's possible to render vertex color it in Octane?
Here's an example of a tiger:
Re: Rendering vertex color / zbrush polypaint
Posted: Sat Mar 30, 2013 8:33 pm
by face_off
Hi. My understanding is that the vertex colour is not used by Octane, so you will need to find a texturemap/uv solution.
Paul
Re: Rendering vertex color / zbrush polypaint
Posted: Sat Mar 30, 2013 8:42 pm
by markflorquin
I thought so...
I can use a texture on the fibers, but the texture will be applied to every single fiber. In the vertex color of the fibers however, there's many more gradients of color. UV'ing millions of fibers is memorywise extremely intensive (failed with 24GB RAM).
So Octane, hear my suggestion: For the sake of quality fur renderings: Make vertex color available for colouring materials!
Sincerely,
Mark
Re: Rendering vertex color / zbrush polypaint
Posted: Sun Mar 31, 2013 12:43 am
by face
Theoretical you need only one 4096x4096 raw image texture to get 16,7mio colors.
Like this one:
http://morris-photographics.com/photosh ... chmidt.png
Each color has an uv range from 0 to 0.000244140625.
Each uv value from one fiber is located at the same uv position.
To set on fiber to the first pixel of the texture you set it to u = 0.000244140625 x 0.5, v = 0.000244140625 x 0.5.
Division by 2 ( x 0.5 ) is to set the uv to the half pixel, because the image is blendet.
For color yellow (255,255,0), which is maybe in you image at position 203,1034, you need only to multiply the position.
u = 0.000244140625 x 203 + 0.000244140625 x 0.5,
v = 0.000244140625 x 1034 + 0.000244140625 x 0.5.
This is what i have made in the Softimage exporter.
But fibers need a lot of vram when the result should looking good.
The image below has 7.5mio triangles which need around 1GB vram.
face