Would any one of the fine people understand this strange shading I’m getting? I seem to be getting lines running along my mesh with a normal map right where the low poly edges are, instead of a nice clean normal like you’d expect from a normal map. The strange thing is that it fades out the further you are from the object. The last example shows how it disappears at a distance.
I should also note that I baked this in xNormal with the recommended settings in the UE4 normal map creation guide, and the results look perfect in Marmoset, Quixel Suite, Substance Painter, and Unity. So this problem appears to be unique to UE4.
This looks to be an issue with your Texture Mip Settings or you Mesh LOD settings. Can you post the settings you are using for the NormalMap and the Mesh LOD setup (if there is a specific one)?
Here are my settings, although I’m not using multiple LOD meshes at this time. Just the one base mesh. I also took a screenshot of the model in the previewer window when you open the mesh in Unreal. As you can see, the model looks great with the normal map applied when viewed in this window. It’s only in the actual level that it has the lines running through it. Not sure if that’s helpful, but I thought it might be pertinent.
So, after looking at your Texture and Model settings, I feel pretty strongly this is a Mip Map issue. Is there a way for you to share the asset and normal map with us for testing? If you would like to keep it private, feel free to send a link to me via the Engine Forums Private Messages.
Ok, so I was right in thought but wrong in type. Are you using Static Light in your scene and if so have you built that light in Production Quality yet or just Preview. It looks like from my tests with the sample that you have some light maps which are showing the light dark seams on the tree. A quick way to test this is change all your light to movable and see if the seams go away.
I’ve been using the default stationary light. I’ve tried building in preview, and high quality. The lines that I have in my reference image aren’t from my UV seams though; the lines appear on every triangle, and are seen clearly on the shadowed side of the mesh. The lines are also present without building lighting at all.
And I have tried cycling between static, stationary, and moveable. None of those seemed to make any noticeable difference to the lines.
From your testing, are you getting lines along every triangle, or just the UV seams? It’s much easier to see on the shadowed side, and closer to the mesh, as mentioned before.
What you are seeing is the SSAO generated by the actual mesh’s geometry, and as that geometry fills the screen it starts to “overwrite” the Normal information.
The good news is you can minimize this effect via adding a post process volume and lowering the intensity of the AO or play around with the Power and Bias settings to allow some AO while minimizing the overall Mesh contribution. As a side note, if you are using a material that is not white, the noticeability of the AO will be minimized as it is added to the Base Color, Roughness and Metallic Passes.
