Normal maps artifacts (Tangent Space / Projection:Box) when using Remesh modifier

Artistic Support Materials and Textures
1

My object has a remesh modifier.

When I create my material and assign a normal map (tangent space/ Box projection), I get weird artifacts in the center of the object.

remesh normal map tangent issue 2
remesh normal map tangent issue 2792×577 278 KB
I reproduced it on a cube, and the remesh modifier is the issue.

I tried with a remesh modifier like in geo nodes, and it has the same issue.

remesh normal map tangent issue 4
remesh normal map tangent issue 4401×207 12.8 KB

remesh normal map tangent issue 1
remesh normal map tangent issue 11230×352 49 KB

My question is how to remove those artifacts?

remesh normal map tangent issue 3
remesh normal map tangent issue 31487×426 78.1 KB

*looks like the face are not correctly oriented.

*I changed “mapping type” from “Texture” to “Point”, or “texture coord” from “Object” to “Generated”, and the artifacts are still here.

*No artifacts when I use a displacement map as bump map.

2

That’s because tangent space normal maps aren’t really compatible with box projection, they depend on UV data for the orientation of their shading and you have no control over that with an automated projection.

It probably looked good before the remesh because the faces were placed differently. The remeshing just made the problem more visible because the topology is more complex and that caused a patch to take a different direction from the rest. But it’s not unlikely that even without the remesh, you would find some wonky stuff happening (like places with inverted normal map shading) if you went searching for it with a light source.

Does the set of textures you are using have a displacement/height map? Use that with a bump node instead of the normal map, that’s compatible with box mapping.

3

Thank you.

I understand more how it works, and indeed, I went to use a displacement map as a bump map, and it fix my issue.