Prevent Emissive Texture Illumination with Lumen

Can anyone shed some light on how I can prevent emissive textures from illuminating/flickering on materials around them when using Lumen. After some research I’ve tried:

  • Switching Emissive texture to translucent
  • Unchecking “Affect Distance Field Lighting” on the mesh with emissive texture. For the heck of it I’ve also tried unchecking “Affect Dynamic Indirect Lighting”
  • Various setting under Global Illumination in Post Processing Volume
  • Playing with Metallic/Roughness levels on both mesh giving off and recieving emissive lighting.




Also some video of the issue:

  • Increase the Final Gather quality from Lumen(from post processing)
    image

  • Decrease the emission value ( mul from your material )

Some note:

  • This occur especially if it a small object ( more if your world is like an Alice World)
  • Using the latest unreal version will reduce this effect ( i believe 5.0 and 5.1 was the worst effect)

Efforts should be around mitigating it rather than turning it “off” so to speak?

no i really would like to turn it off myself… Lumen is not necessary if hte light itself has an actual spot or point light on it already. Plus its getting in the way of lighting a scene with real world units and bloom… if i increase the emissive to match the lumen value of a real world light to match bloom on things the light hit vs the light itself… i need to crank lumen way up… im talkn multiply the emissive to 300k or more for it to look right next to the light itself … Right now i wish i could just disable lumen emissive lights completely… if i cant do it per object id rather not have them at all… Emissive with lumen is pretty ■■■■ bad .

Upping quality levels is not a solution if you are trying to have good frame rates on low end machines. Plus that doesnt fix any of my issues eitehr way.

Quality issues aside… it sucks for setting up real world unit lighting.

At this point im thinkn about just giving up on lumen… its been a terrible year long journey… for my current project. I managed to get the cvars setup for great quality and great performance… but this emissive stuff is killing me… Just adds random splotchiness to the environment… espeacially if u increase emissive to a really high level… ull see bright spots where there arent even lights… and im talkn giant bright spots 2 buildings away from the street light itself

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I turned it off in the days following. Really haven’t looked back yet. I bumped up performance too turning it off.

You mean you managed to turn off the effect for that texture / object? Or turned off Lumen altogether?

Coming from offline renderers - it’s weaksauce if you can’t turn it off at the object level.

I was just thinking that if Megalights render many times faster, we can use more of them to simulate light bounces and switch off everything else

Lumen as a whole…for now.

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