Hi, so I am creating an interior level, this level is currently using lumen and nanite and looks great on my RTX3070 and runs at 40-60fps. However I am very concerned it will either look terrible or run like a donkey on low end hardware like a GTX1660 or 1650.
I started learning unreal with Lumen so I dont have a lot of experience with bake lighting, but is it even possible to bake lumen lighting as a fallback at the moment? Because i’ve read in a few places this might not be possible yet.
Also I guess another question I would have is how do I set up fallbacks in case a system doesnt have ray tracing capabilities etc? Even if you know some documentation I can read up on that would be a great help thanks!
If you’re getting 40-60 on an internal scene, then it’s more than Lumen that’s slowing it down 
Basically, nobody has RTX cards and with that goes hardware ray tracing. In the gaming community, the 1600 series is by far the most common card, still ( Steam survey this year ). Low end would be 1000 series or 900.
You can’t bake Lumen, but you still can bake static lighting, just like you always could. A big pain in the bum though, if you’re used to dynamic.
I hate to say it, but you might also want to turn off Nanite, which I don’t think you can at runtime. So you’d probably need 2 copies of everything.
What kind of user are you targeting?
The plan was always to have high a fidelity expereince, so I not worried about sacrificing some level of accesibility.
When running some basic profiling checks (i’m very new so dont understand all of it but followed the official guide) I saw that the game thread was getting 4-5ms, with the draw and GPU both higher at around 19-20ms. Pretty sure this means the GPU was the limiting factor meaning it was likely lumen and the lighting that was causing the biggest performance hit.
As for my target user, i’d like a mid range card to be able to get 60 at medium/high settings. With low end cards targeting 30 at low/medium. But because I am focusing on high fidelity I really dont want to sacrifice the awesome global illumination from Lumen… even on the low end systems.
If there is a way to toggle lumen and nanite only for the higher end cards, and then fallback to baked GI i think that would be the best option, but I wouldn’t know where to start with that.
I agree, Lumen does look awesome.
You can toggle Lumen with a console command, be interested to see what fps you get with it off
r.DynamicGlobalIlluminationMethod 0 ( or 1 )
I don’t think you can toggle Nanite ( would love to be corrected on that ).
It might be a good idea to actually try this on a low end card. If you’re getting 40-60, I would think a 1050 would be right down at about 5 fps.