Hello,
This flame vfx on my torch casts light onto distant meshes as seen in this video.
flamevfx
My project uses nanite and lumen and is 5.1.
The only way I’ve been able to fix it temporarily is using this command:
r.Lumen.ScreenProbeGather.ScreenTraces 0
Does anyone have any advice or know a solution? If you need any more details let me know.
Hi,
I believe that Lumen use some kind of Screen Space global illumination so I don’t think there is a fix for that unless using full raytracing. Are you able to try the comparison between raytracing and Lumen ? Is it the same ?
I’m curious to see the evolution of this thread so I’ll follow along 
Thanks for the suggestion. Changing the global illumination method to ‘screen space (beta)’ or ‘deprecated ray tracing’ fixed this issue, but then takes away the benefits of Lumen of course.
I would have hoped they’d be a way, at least in 5.1, to fix this issue with lumen? Any other suggestions? Here is a screenshot of lumen vs ray tracing/screen space methods.
Happy this helped
Maybe you could try to reduce the emissive from the fire ?
Do you have lights in your particles ? (Not a pro in Niagara)
I can see in your screenshot that, those options are in the project settings, have you tried to adjust them in the post process volume ?
I don’t see a lot of reflective material in your scene, have you tried to use Screen Space reflection to see if the issue persist ?
Also, try turning off ‘use hardware Ray Tracing when available’ to get a true feel of Lumen. This option give you Raytracing even if you try to use Lumen - which might give you different result (for instance, on play mode your image might be brighten up (at least it does for me).
Hope it help!
Hey Krimson,
I tried your suggestions, and have spent hours trying to figure out a solution to this but to no avail. I think the problem stems from emissive materials not having a feature to turn off their emitting light. Other users have suffered from the same problem it seems.
There are lots of examples in games where we want emissive but don’t need to light the environment with it, such as highlighting a collectable on the floor, so it’s sad not to see this feature yet.
The best I have got for now is this command:
r.Lumen.ScreenProbeGather.ScreenTraces 0
Because I keep the benefit of Lumen but turn off the issue. Although i can still see reflections in the distance.
If there’s a fix for this issue it would be amazing, but for now i will wait and hope 
Cheers!
Hi,
Sorry it do not worked out. As I was trying to find some more information, I found out a thread saying exactly what you said. Even with the console command as a temporary fix haha!
So, I think we just have to wait then.
Hi all
It’s been around 8 months since this post and i was wondering if any update or new method has been found to stop emissive materials lighting up meshes with lumen?
Use cases: emissive pickup objects or torches or candles that shouldn’t light up distant meshes.
