Hi! I’ve added a few static lights to my scene, I’d expect the light to bounce from the floor/walls to the ceiling, however, that’s not happening and the ceiling is left completely black. How can I fix this?
Hi!
Maybe you don’t have a lightmap uv assigned to the ceiling mesh… or it’s just empty…
Could be that its normals are flipped…
It doesn’t look the same to me… there is obviously lighting information there now!
Even in the preview it look almost black!! ?
Is the material fully reflective? …do you have reflection capture in the scene?
All your “meshes” are just planes? Any of them have proper thickness?
Do you use any other light than emissive? /emissive is controlled by the skylight bounce…/
UVs and lightmap resolution seem okay.
It doesn’t seem to be caused by the mesh itself, I’ve tried replacing the ceiling mesh with a flipped/rotated floor one, same issue.
The floor material is almost fully reflective, though the ceiling material isn’t. They’re the same meshes except the ceiling one is flipped. It’s a modular project so the tileable meshes (walls, floor, etc.) are one-sided.
All imported meshes (props included) and materials have almost completely black shadows in the preview window. (see attached image)
I have no reflection captures in my scene due to another issue I posted [here][2].
I have a static rect light placed, by setting the environment color in the world settings to white, and by using a static point light I do get some light on the ceiling, but still no bounced lighting. (see 2nd image)
I’d also like to add that I don’t get this issue in a room lit by directional/sky lights, using the same mesh.
Sorry, I can’t help: I never use 1 sided planes since Unreal needs thickness for proper lighting calculation…
I’ve just tried replacing the ceiling mesh with a cube from UE’s engine content, it’s still pitch black. It’s not the mesh thickness
Why would not having mesh thickness cause a black lighting? It would cause leaking, but I don’t know how it would cause it to render black where bounce lighting should light it up.
Is the mesh lit on the outside of it? What are the directional light settings? It’s a directional light that sometimes requires modifications to receive more lighting indoors, while skylight needs a boost in intensity scale to do the same (or a change of cubemap). The issue is most likely either directional light and/or settings for the mesh. Post a screenshot of all lighting settings for the directional light, and the Build settings of the ceiling mesh (not the new UE cube one you made, but the old one if it’s still in the scene), and I’ll have a look at it, try to understand by testing the settings myself perhaps.
I think I figured it out. I’m using layered materials in my project and by replacing the material on the floor to a non-layered, but in every other aspect completely identical one I’m getting bounced lighting on the ceiling.
I think you should’ve answered your question and mark THAT as answer! 
I’m glad you’ve found it!!
That’s what’s causing the weird reflection too?
It’s a clear coat material so I think it’s that. That behavior is gone with accurate lighting
Which is the clear coat material? The tiled floor or the ceiling, or both?
With the clear coat, you can set “Use Full Precision UVs” and/or “Use High Precision Tangent Basis” in the mesh editor Build settings (which you posted). First, you need to enable “Use High Precision Normals” in Project Settings > Rendering > GBuffer format (it’s a dropdown list). It enhances various things, one of which is reflections by making them more accurate, from what I’ve read in a tutorial and in the doc pages.
You should also enable Transmission in the Skylight and Directional Light, and enable Affect Translucent Lighting in the Skylight. Those settings have observable connection to clear coat materials. One last suggestion: increase the Skylight cubemap resolution to 256 or 512, as it makes reflections and other rendering aspects more accurate and better quality.
The clear coat material is the floor, however, it’s the layered materials that are causing the lighting issue. If I create a basic one with one layer (background only) and with a vector3 as base color and assign it to the floor it doesn’t let static lights bounce for some reason. Create an identical generic (non-layered) material and I get accurate, bounced lighting immediately.
Thanks for the suggestions, I’ll be sure to look into those settings.