UNREAL 4.19 - Why Rebuild lights ruins shadows and creates squared artifacts? - image attached (B&A)

Hi, I wonder why “rebuild lighting only” ruins shadows, specially on large objects… i actually preffer my scene without rebuild, but i wonder why this happens?

I attached an image of my mesh before and after rebuild shadows (my mesh is massive btw), after press rebuild lights… squared artifacts appear in my shadows, what can i do now and what can i do to prevent this?

Thanks, please help

before you build lighting, ue4 uses dynamic lighting, the same as if you set your light to movable. when you build lighting, you need proper lightmaps set up, and if you just build on preview, it will look pretty bad. on large objects, you need larger lightmap resolution and or split the mesh into smaller parts.

heaps of information about it in the docs :slight_smile: