[UE5] Light cast by emissive materials disappears after a certain distance (Lumen + Hardware Raytracing)

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.

For example:


Goal would be to extend this distance at which lighting is no longer visible.
Any help would be greatly appreaciated.

Thanks!

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[…]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.

Source:

2 Likes

Hi! I have the same situation. Did you find any solution?

  1. Make sure Emissive Light Source is enabled on the meshes that emit the light:
  2. Make sure the meshes with Emissive materials have Nanite enabled
  3. Try increasing Lumen Scene Detail in the Post Process Volume Lumen settings:

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:

3 Likes

I’m also having a similar problem. @Rawalanche, unfortunately in my case it didn’t solve the problem. Has anyone found a solution?

Did you find any solution?

Hello, i just discovered a solution, you have to increase Max Trace Distance in the PPV (Lumen GI). It was set by default to 20000, and i added another 0 and the thing is done.