Weird shadow lines drawn on my lightmap ?

Hello !

Sorry to bother you, but I’ve been trying to solve this for several days now. I have a floor made with squared tiles. It’s not done with a normal map, it’s all in geometry (about 2000 tri). There is no overlapping vertex, the geometry is clean, and my normals too in maya.

I have 2 UV set, the first one where all my tiles are overlapping (I’ll be using a tiling material), and the second one with my floor in top view. The first one is used for the material, but the second one is used for the lightmaps. I’ve changed the value for that in the source lightmap index menu, and it’s all correct.

I asked a friend to try on her laptop in a new project and she didn’t get any problem, so I’m pretty sure it’s something wrong in my scene and not the mesh, the UVs, the normals nor anything. Something’s wrong in unreal but I can’t understand what. Here’s the problem so you can understand what I mean :

Those black lines, those unwanted shadows along my tiles, I just don’t understand where they are coming from ! If anyone has an idea of what the problem is I’ll be glad to hear it :frowning:

Thank you for the upcoming replies (I hope !)

Hello .colas -

So there seems to be a few things that are happening with your model.

In the first image, inside of Maya, it appears as if you have seams everywhere. The thick green lines are indicative of where your geometry does not meet.

That’s the pre UE4 issue that I see.

Inside of UE4 make sure you have assigned the light map channel to your mesh inside of the meshes detail panel.

I am going to link you our lighting troubleshooting guide on our wiki.

This should help clarify/guide you with any lighting issues that could be occurring in your scene.


Hello .colas,

I haven’t heard from you in a few days. I was wondering if you were still experiencing this issue?