Lighting error disappears after changing build settings

Hi everyone,

I’m new to unreal, so this question may be kind of stupid:

We, a small team of students, are trying to build a walkthrough through our faculty building.
Our modeling guy created the building with around 500 meshes without texture, just some colors. When I rebuild the lightning for the scene it says that most of the objects have overlapping UVs, as you can see in the screenshot (built with “Use error coloring”)

The odd thing I’m wondering about is, that when I apply changes on the build settings in the mesh editor, for example, change the “Min Lightmap Resolution” from 64 to 128, apply, change it back to 64 and apply this happens:

The lightning error on this wall disappeared and is now working as it should.
When I rebuild the light, the error shows up again.

Can anyone explain this to me?

Thanks for the answers and best regards,


Open up the object mesh file and set the light map cordinate index to 1, that typically fixes it for me. If it is a custom model, if you use blender just go to edit mode and press U to unwrap it and then export it from there and it should work.

Thanks for the fast answer :slight_smile:

Changing the lightmap coordinate index to 1 didn’t fix the problem. It just looks different now:
The first one is with index 0 and the second one with index 1.

I’m not that into modelling, but I think the problem with your second approach is for us, that the building consists of over 500 small parts. For this approach, we would have to unwrap every single one right?