Chaos Corona Forum
Chaos Corona for Cinema 4D => [C4D] I need help! => Topic started by: KAB on 2023-03-09, 18:21:57
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Hi
I am currently rendering a carpet using the carpet material from the Corona material library: Carpet Office
Here a render error appears that I often have with displacement textures: if I have a surface that consists of multiple polygon lines, the texture makes errors (see picture in the attachment) The green floor has strange dark green areas that are not shadows! These spots are exactly along polygon lines.
Now I have melted the polygons to a surface and still, these dark spots appear. It does not matter if I use UVW oder Cubic texture mapping.
Do you know any advice?
Thanks and Best, Katharina
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try to subdivide or cut the surface in even parts in u and v, so it is more even tessellated.
in my expereince this happens if the surface is badly triangulated with long small triangles (like with n-gons and their hidden tessellation, or imported cad geo)
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Hi there, can you provide a scene for us to look into further? If so, please feel free to use to the link in my signature below.
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On further investigating, I see that this has been reported by another user. It seems the artifacts are from bad topology. Can you please check your mesh? Was it imported from elsewhere?
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=39560.0;attach=180244;image)
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I'm no doctor, but if indeed you have models you didn't create and it will be unreasonable to try and fix the mesh, for a flat surface like that the handy Cubic projection setting would work even if the topology is bad. Usually. Just have to adjust the scale to make sure it's right.
This example is a little extreme, but it's a Cosmos rug object, made editable and stretched quite a bit. The topology isn't bad necessarily, but by stretching it creates long triangles. The carpet is from the library. On the bottom is the material set to follow the UVs. Not so good, a little different than your issue. The top is the same object and the same material set to Cubic. Since there isn't a specific need to follow those UVs (which I struggle with) on a flat surface, it's a much quicker solution in many cases.