Lightmap Issue UE4

Garasin

Hey guys,

I'm having an issue in UE4 with my modular wall tiles (static meshes). The shadows on seem to be acting weird on them whenever there is no direct light on them. I've had this problem in the past and I always got around it by just using BSP instead but this time I'm using a modular texture for my walls, floors, ect.

I was wondering if anyone knows why this is happening and how to fix it?

Here's some images of the walls in shadow and in direct light as well as my lightmap in 3dsMax.

Thanks!

Harbinger

You're never going to get perfectly clean shadowing/lighting across pieces like that. Perfectly flat modules with very clean texturing will always show some type of variation. In fact, you can even see it in the dynamically lit version you posted.

That said, there are some things you can easily to do minimize or eliminate it by changing your strategy with those pieces.

1) You hit the nail on the head - why are these separate modules and not a tiling texture on BSP? Or a single continuous static mesh? If you don't absolutely need them to be static meshes, you'll get cleaner lighting on BSP or a merged mesh.

2) If you want meshes, realize you are going to have some seams and plan that into your design. The design you made has a perfect place to hide seams... in the seams. Shift your design over 50% so the edges of your mesh align to the edges in the wall panels.

3) Your lightmap UV's don't look very efficient. You've got too much padding around the edges, and I'm not sure why it's split up into multiple islands. Aren't these meshes just flat planes? Just planar project the entire mesh and fill up the 0-1 UV space.

Take a look at this doc:
https://docs.unrealengine.com/latest/INT/Engine/Content/Types/StaticMeshes/LightmapUnwrapping/index.html

Hope that helps!

electricsauce

It's a common problem with lightmass right now with no expected fix date. There was a suggestion to change the static lighting level scale in lightmass, but it didn't work that well for me.

https://forums.unrealengine.com/showthread.php?4706-Adjacent-planes-are-lit-differently