Maya normal map artifacts on low poly edges.
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Hey so I'm having this issue with my tangent space normal map generated from a high poly mesh in maya 2011. Pretty much anywhere the low poly mesh does not have nice uniform quad modeling I get these pixel stairs where the low poly triangle edges are. What am I doing wrong. Doesn't seem to matter how I triangulate the mesh it just moves the problem around but it's still there.
Replies
#1. Maya renders excellent normals, even over extreme angles, because of this, we're less likely to use hard edges.
#2. Normal maps are limited to the resolution of your texture.
#3. Small-thin triangles, which also have extreme angle changes resulting in very "gradiated" smoothing(and graduated normal maps as a result to compensate) push the boundaries of what is possible. You simply run out of resolution as your triangles are smaller than your pixel(or smaller than the minimum required to represent a gradient).
To fix this, you can:
A. Avoid these long thin triangles
B. Use hard edges along your uvs seams, if your uv layout is pretty natural this generally just works. There is a maya script that Mop posted somewhere on the boards if your search for it that does this.
On a related note, this is another reason why chamfering your mesh instead of using smoothing groups isn't always a good idea, as these sorts of long-thin triangles are prone to errors even when your baker/renderer are synched up.