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Strange artifacting with geo : Shading derivative


garretthoyos

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Hey I'm having a strange issue. I modeled a fosset to shade but the S & T are just strange. I'm confused since I thought S and T were suppose to have everything to do with the UV map 0-1 space. However, here (see image) I am getting some strange results which cause my shader to appear almost at random. I dropped in a perfect asset (shirt geometry) that works perfectly in production when I textured and shaded it, but as soon as I plug in the S into the color ouput of the material shader builder it appears super strange. I'm confused at why I'm getting these results. 

 

Thanks

post-10667-0-24889300-1393558913_thumb.p

post-10667-0-64421300-1393559174_thumb.p

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s and t are the implicit coordinates, going from 0 to 1 across the current primitive, be that polygon or mesh or patch. You want to use u and v, and those need to be created with a UV Texture SOP or its brethren. The shaders default to using s and t if the uv-attributes are not present.

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Thank you for the reply. I think my biggest question really is about mixing Normals into the derivative of S or T. It uses the S or T value that comes out of the box and not the one that comes from my UVs. I want to find the edges of the object but there are places where it looks bad. 

post-10667-0-15184900-1393621124_thumb.p

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