I have been trying to enable Realtime Global Illumination using Lumen in UE5. When I try to enable it nothing happens and I can even bake my lights because I think I need to turn off precomputed lighting. I’m super new to UE5. I’ve been following a tutorial for a simple lighting setup and I’m stuck. Does anybody know how to enable it?
Greetings @davey4553 !
We see that this is your first time posting! 
Welcome to the Unreal Engine community! I’m sorry that you are having issues with Lumen in UE5. Until one of the Rock Stars of the community provide you with some great suggestions and possible solutions, please consider looking at the threads here and here. Also, what are the specs for your GPU?
Thank you for being an important part of our growing community, and I wish you the best of luck in discovering solutions for the problem you are having with Lumen! 
I have an m1 Mac air 2020 with an 8-core gpu. The issue may just be that I’m trying to run it on Mac, but everything else has been running perfectly on it so far. I have 8 gb of ram.
I don’t think it is available on a Mac right now.
oh, thank you, ive been driving myself crazy for like 4 hours trying to figure this out. That stinks though.
I don’t know much about this myself, but by chance I was having problems with this too, so I investigated this a little bit yesterday.
The only thing I found out, is that global illumination can be disabled in the post process volume. It is set to Lumen by default. I would really like to control it’s intensity but I didn’t found where this can be done.
I watched something about that, and if your computer runs slower using Lumen you can go to project settings, rendering, and then Lumen, and you can turn software ray tracing to global tracing and it should run better. Although if you use hardware ray tracing then I don’t think it’ll work.
I’m going to check this as I’m in a somewhat weak PC.
hi, I had the same issue, I fixed it by setting the Scalability > Effect > High ( Or Epic ) and setting all of your light elements ( SkyLight, Direct Light, SkyAtmosphere ) To Movable
Also Go To Show > Visualise > Lumen GI and if u see the light bounce it means its active
this is the method that worked for me , hope it works for u
Thanks, I’ll give it a shot, but I think on Mac I’ll probably be restricted to raytracing.
check out this video on youtube : Lumen | Unreal Inside
the technical team explain everything about Lumen, according to this video: There is no limit for using lumen with any Hardware ( dont get confused with Hardware Ray tracing, Lumen is a Ray Tracing Feature but its software Ray Tracing and there is also an option to use Hardware ray tracing with Lumen for more accurate result , if you have a GPU ( doesn’t matter Integrated or dedicated ) you should still see the Lumen result in your scene , you might experience low fps but you should see Lumen working , my PC spec: Ryzen 5 3600X , RTX 2060 , 16GB RAM but still can’t get good fps ( around 40 with simple Third Character Template ) And i also should mention that my laptop has an integrated GPU ( Ryzen 3500U with iGPU Vega 8 ) it’ll Run the UE5 and i can use Lumen but fps is terrible ( Around 6 )
but you should give it a try, Lumen And Ninite are so great