Normalmap from diffuse texture problem

I made a normalmap from a diffuse texture for a bell. But when I add the normalmap then… please look at the image! On one side of the seam it’s really glossy on the other side not.

Without the normalmap the diffuse texture looks fine and you won’t see a any difference on both sides of the seam. What can I do to fix this?

image image

It’s probably not really glossy on one side. It’s just that it’s reflecting the (hidden) world, which has lighting on one side and not the other, and your normal map makes it divide differently at the seam.

You’re not likely to get valid normals by making a normal map from a diffuse, but of course, you didn’t mention what steps you took to do that. There are some things you could do that would only be kind of bad, and some things you could do that would be really really bad. Beyond that, a tangent space normal map needs to be built with a knowledge of the UV tangents of the mesh: it is specific to a particular mesh, and there’s no way to make one without taking the mesh into account. (Kind of true of an object space normal map as well, but in a different way.) So if you were trying to use some 3rd party utility to make a normal map that never even let you load an .obj or something, well, that’s just not a valid way to do it.

Thanks for your answer. I played a little bit around and found a solution. I didn’t turn my texture to non color before baking x)

Ok. Even if it works now in some way I’m not satisfied with the result. I guess it was dumb to bake the normalmap in Blender from the diffuse image.

The problem is that I painted the texture in blender onto the mesh. If I use a software like awesome bump it would also lead to the same result. So is there a way to get a good normal map from my diffuse image? Without the shading issues I have on both sides of the seam. The light comes actually from the side, so I guess the normalmap does actually show the world around the bell.

A diffuse map is not a great way to make a normal map.

If you want to use a diffuse map as a normal map, the best way is to use the diffuse value as the height for a bump map-- either via a bump node, or via material displacement.

If you want this as a normal map, you can set the bump/displacement up and bake tangent space normals for the mesh.

Something like awesome bump basically does the same thing, but if it’s just working on an image, and you never load a model into it, then it can’t really do it right, because it doesn’t know what your mesh’s tangents are.

Baking from the bump in Blender does work better than using awesome bump. Now I’m trying to bake specular and roughness maps in Blender but it doesn’t work. As far as I know it is only possible to bake these maps if I bake from high poly model. Or is there a way to do it in blender?

Plug whatever value you have for roughness or whatever into emission, bake emission.

That’s great. Finally I can do everything right inside blender. Thanks for all the answers.