Hello everyone, I was so happy that I finally finished my first scene in UE4 until I decided to try and bake out the lightning. It appears that my shadows and light-projections are entirely incorrect in almost every single way possible. Does anyone know what the problem might be?
I added a few screenshots to showcase the problem:
One thing that I find extremely weird, is that I turned off the shadows for the curbs, sidewalks, and roads. Unreal seems to ignore this. Also, some meshes don’t even cast any shadows, although this option is enabled
Add a Lightmass Importance Volume around the entire scene.
Certain meshes have overlapping UVs for lightmaps, so that’ll cause incorrect results.
Certain meshes have wrapping UVs (the 2D version of the 3D mesh goes outside the lightmap border, when it has to be in the 0-1 space)
Is RT enabled?
Check into how to create correct lightmaps. There’s some instructions and tips in the docs, and there’s tutorials on youtube. If using dynamic lighting for part of the scene (such as RT, or without it, any non-RT movable/stationary lights), then it may require research on how to combine those with static, baked lighting for the scene.
Hey, thanks for your reply. Adding a lightmass importance volume didn’t solve the problem. Also, the sidewalks for example, which stand out the most, don’t show an error for overlapping uvs. Ohw and none of the lights used are dynamic
I managed to figure out what was causing the problem. Apparently you need to set the lightmap-resolution for all single meshes which make sense, but I didn’t know this because I’m still a beginner in Unreal. I set the resolution 64. I don’t know why it has to be 64, nor do I have any idea how the resolution of Ligtmaps are determined, but it solved the problem
A Lightmass Importance Volume most likely wouldn’t solve everything by itself. It could help though in certain cases.
The sidewalks appeared to have shadows that belong to non-existent meshes, with most of them having the same basic shape. This type of shadow leaking is often attributed to DFAO (Distance Field Ambient Occlusion).
Lots of designers have had issues with instanced foliage and lighting. The issue often seems to be lightmap UVs don’t get correct lighting due to not having lightmap data generated for each specific instance and where it is in the scene. I’m not sure if that’s exactly it though for that one.
So, setting LM res to 64 for everything (foliage, houses, fences, sidewalks, etc) solved all the lighting problems?
No, setting the Lightmap resolution only solved the problems I was having with the road//sidewalk-meshes. The overlapping uv errors are still there. For now, that’s fine because the majority of incorrect lightning optics in my scene were a result of the road/sidewalk- meshes. When I get to a more final stage of the project, I’ll also start looking into the more specific lightning inconsistencies.
