Hello, I’m currently encountering an issue with night time lighting in a project (UE5, Lumen + Hardware Raytracing).
I’m looking at lighting the scene with emissive materials during night time (so street lights and interior illumination for buildings) as a large number of lights seems to destroy performance.
The issue encountered is that lighting from emissive materials simply and slowly disappears when putting distance between player and said emissives.
[…]Lumen culls small objects from Lumen Scene for performance. In the Post Process Setting, Increase the Lumen Scene Detail will capture smaller meshes over farther distances.
Small objects are culled from Lumen Scene leaving only the Screen Traces to pick up small emissive meshes. This leads to inconsistency in their lighting in the scene. Set the Level instances Emissive Light Source from the Details panel.
If none of the above help, it is likely that the Light meshes are still getting culled from the lumen scene at distance. You can force them to cull at much larger distance by increasing their bounds in the Static Mesh Editor:
