Modular walls Lightmap issues


This being my first experience with Unreal, I have been trying to build modular walls in 3d studio max and importing them in Unreal, but I keep having issues with the lightmap as you can see in the picture below.

Now I’m aware that this topic was brought up before, I did some research. I added a second UV channel in Max and spaced out the clusters to avoid artifacts, it is much better than my first few attempts but I still get issues. Can anyone help and tell me what I’m doing wrong? Or is it the way I planed my modular walls that’s wrong? My walls are built with blocks but it seems to cause a lot of problems. I’m also aware of the seam beside the door.

Thank you for your assistance.



The shadow blotch on the left looks like low lightmap resolution so bump it up to 128 or above if it isn’t already

The seaming on the right wall is going to happen all the time because of how ue4 renders on different threads. For big contiguous walls like that, they’ll have to be one piece and not split up I’m afraid

I see. Alright, I’ll try to approach this differently.

Thanks JLO

There are a couple of things you’ll want to do with your modular pieces here.

It’s best to break the assets up so that each “modular” piece is it’s own model and not sharing UV space with the other pieces. This will give you better resolution for your LM without having to turn up the resolution for the LM in UE4.

You’ll also want to make sure you’re setting up the grid properly in your UV so that each hard edge is snapped to the grid for the LM resolution you’re targeting.

For more information take a look at this thread for setting up the grid spacing and typical Modular workflows.


Thank you very much Tim, I’m sure I’ll find all the information I need in that post.