win10 2021.16490
Some prims don’t unwrap properly. Bug or user error?
issue.tox (1.2 KB)
When dealing with low resolution images and normalized coordinates the key is to think about a pixel that has a real width to it, and a coordinate that is infinitely small. For a pixel to get rasterized the primitive needs to pass a rasterization test for it, which can be different for different GPUs, and depends on the primitive type (line vs triangle).
In this case the UV unwrap is trying to place the lines exactly on the edges between the pixels. How the GPU decides to rasterize these lines is arbitrary, it’s an edge case. If you want to ensure those pixels are rasterized then you need to ensure the line is clearly within the pixel. A tiny offset in the Texture SOP will do the trick.
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