Lighting breaks on simple geometry. Is nobody else having this issue?

So I’ve got a problem I’ve been troubleshooting all day to no avail.

Built a super simple little building (416 tris) with no overlapping UV’s:

But when lighting gets built in unreal (4.12.2):

The other, higher detail stuff I did works great:

I’ve been using UE4 for years and I’ve never had this before, what am I doing wrong!?

You clearly haven’t made the blood oath. It’s really the only way.

Have you checked the vertex normals?

Also when you open the model in Material editor or in Static mesh viewer (ie no baked lighting), how does it look?

Looks to me like you’re using a low-resolution lightmap, have you checked over here to see if you’re having a similar issue?

Hey, concept artist for the project. Without baking lighting it looks great, no problem at all. We started with a 64bit lightmap and have since upped it to a 1k lightmap. The picture above is of the 1k map.

It looks great without lighting build (nothing up with the normals or smoothing groups), just goes sour with baked lighting regardless of build quality.

I’ve tried it with lightmaps from 64 up to 4k, it breaks over all of them!

New important note: It is fixed at the same lightmap resolution when scaled huge. but it’s too big for the game!

Try playing with the lightmass scale, something like .1 or .01

Your lightmap UV’s are not very good, you split it up far too much
Also, you have a bunch of intersecting pieces, which will cause issues because the areas of the polygons that are hidden will bleed shadow over onto visible areas. Also, the small parts are smaller than a pixel so they will not look good. And, you need more space between UV islands.

After fixing your UV’s you’d need to adjust your lightmap resolution