How To Solve This Issue with Triangles and Smoothing Groups?

mrgesy

I have baked a normal map to an object with one smoothing group. The low poly looks very smooth with the normal map, but when I bump up specularity, triangles start to become apparent on its surface. How to get rid of them?

Screenshot in attachment.


Wireframe Added.

Equanim

Can we see wires of your high and low poly meshes? It looks like one has a pole (vertex that connects more than four edges) that's causing your issue. Even if both meshes are perfectly flat, that kind of thing can pop up if the topology isn't well distributed.

mrgesy

ALso I welded several edges to one vertex to decrease polygon count for games

Equanim

Yup, looks like that's your problem. Normal calculators tend to dislike poles with too many edges attached or really long, skinny triangles. You can fix it by dividing up your geometry a bit. It's a few more tris, but it'll look better.

If the area you're getting distortion on is going to have a really high contrast, noisy material (like rust with a lot of dirt and grease) sometimes you can even get away with that distortion and not have to change anything. If the surface is smooth and clean though, it's worth the extra tris.

mrgesy

Thanks! I understand the problem now.
I will go ahead and rework the mesh.

huffer

Do the triangles appear in the baked normal map too? There's an issue that shows up if you bake the normal map with Vray - some faces appear faceted, and I think this could also happen if there's a normal map mismatch between programs.

JonathanLambert

Try exporting your mesh as a OBJ, I've had issues with FBXs in Marmoset.

mrgesy

@Huffer,
Yes the triangles appear in the normal map also, but actually look smooth on the model. I baked it with XNormal