Lumen + stationary light - spotty flickering?

Development Rendering
,
1

Animation2_a

  • I already tried turning the lights to Static and baking it: nothing.
  • The effect is much worse in the CineCameraActor (and in gameplay, but that’s a lot less relevant).

The set-up:

  • Light from SunSky
    • Dialed down the directional light to 1 lux.
    • Mobility is all set to stationary
    • Does not matter if it’s day or night
    • Turning it off helps a lot, but the effect is still there
    • Switching it to just a directional light also helps, but the effect is still present
  • PPV
    • Standard bloom, intensity 1.0
    • Exposure manual, compensation 10.0
    • Lens flares
    • Played around with some camera settings
    • Playing around with all the other settings do not help
    • Turning it of kinda makes it worse/more pronounced, maybe because it gets brighter
  • Volumetric cloud
    • Everything except for the layer heights are default
  • Exponential height fog
    • Volumetric fog is turned on
  • Static meshes
    • Generate lightmap UVs is turned on
    • The texture UVs do overlap, and they cannot be edited
    • All the meshes were exported directly from a non-UE game from 2011, absolutely no modifications were made and no modifications can be made (because it’s a lot)
    • Some materials are emissive.
  • Other scene lights
    • Almost all are either stationary rect or spot lights. Changed nothing except for the size/angles and the intensity (~1 to 8 lux).
2

Lumen does not support stationary or static lights, there’s no point in using them, you also do not need lightmap UVs.

Most common causes of noise are:

  1. Small/far away emissive surfaces
  2. Small/far away lightsources

You should also look at the lumen debug views, they should match the scene pretty closely, if not, you will have problems.

1 Like
3

I’m working on a “not playable, just rendered, all static lights” project, so I don’t mind long build times.

I switched to Screen Space and it does look much better (like the spots are gone), but it’s also a bit darker. Will I have to put in all the light sources manually? And now it’s complaining about overlapping lightmap UVs…