Nanite rules! lumen... not so much

so this is 48x 651k triangles mesh in 4.25

and this is the same mesh but 224 times (~150mil triangles!) using nanite

and a terrain as a static mesh @33.5mil tris just for fun :slight_smile:

sorry for the crappy vids, youtube…

and as for lumen

getting mixed results

seems to be happening to others as well, especially when porting older (UE4) projects

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Yes, Lumen is very, ver buggy, i am doing a similar warehouse scene like the one you showed on the last video, even the lighting enters the room in a similar way, but i have the same artifacts you showed on the other Lumen video and way way more other issues, like green pixels appearing randomly, and some splotches dancing forever even when the camera is still, i´ll post a vieo and images later.

Since this is ealry access it´s important to give epic feedback, but it´s a little bit concerning how much this will improve by the time they release 5.0. In the last stream they said they priority is to make nanite draw more instances instead of adressing things like vertex painting, displacement, one sided meshes and other more important things for actual game deveopment, and with lumen who knows.

This is with hardware raytracing enabled? This looks like it’s just SSGI.

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not raytracing, lumen


tried both and played around with all the options…

People have the impression that with Lumen you can just drop your scene in and it’ll work perfectly, and that’s not the case, take a look at the documentation

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People have whatever impression is given in promotional materials. If you say it just works people might expect just that. Of course most people dont and they try for themselves to see if it actually “just works”.
Of course i read the docs and watched all the vids about how to set it up but… results may vary, idk.

i’m still trying to figure out stuff…

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Just throwing the question out here: You made sure the Postprocess volume is set to unbound?

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Please read the official Documentation properly before posting this here. It clearly states that Lumen in UE5 EA doesn’t do well in interiors (also does not work with landscapes currently but will be in 5.0). That being said, according to docs there are major improvements for Lumen interior lighting and noise in the 5.0 release and beyond.

Lumen will “just work” in the 5.0 not in EA.
EA is not the final 5.0 marketing promised.

If you’re interested you can check out yesterday’s Nanite livestream with Brian Karris here: Twitch

Nanite will support WPO,
Nanite will support vertex painting (this one was from the previous week’s livestream)
Nanite will support Masked materials, but not translucent.

Next week will be Lumen, If you need, you can address these issues in the forum thread they post before a day.

Take Care! :slight_smile:


“It clearly states that Lumen in UE5 EA doesn’t do well in interiors”
it clearly doesn’t say that.

ok, i get it. i know what early access means. its great that it will be even better when it gets out of EA.
i was just testing and reporting on how things are right now.

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And do you realise that this is early access and the puprose is to give feedback and show apic all sort of issues so they can fix them? it doesn´t matter if the documentation says x about interiors, this is not an expected behavior even for early access.


Don´t listen to them, if you keep getting issues keep posting them, that´s the puprose of early access.


I’m not sure, I use an older macbook pro for iPhone development and tbh switching to lumen gave me an extra 2fps, had to disable it though since it’s unsupported on mobile. But in general it seemed like a huge improvement to me.

I’m getting issues like that as well, Lumen GI vanishing when camera is close to a wall. It’s definitely a bug though, so it’s good to report it.

Unless I’m mistaken, we all have the same build so we all should get the same problems unless the issues are caused by hardware or software specific to your pc.

Can’t speak for the rest, but I would lile to help understand this issue, because one day it might happen to me at the worst possible time. So please let us know if you are still having problems. Your current settings for lumen and hardware could help us have a better idea.

if i find the cause i will post it here

are you a bot?

Unreal Engine 5 is literally like a lottery. Some people experience issues that others don’t. Some people get excellent performance, others get terrible performance, regardless of their setup. Performance of the engine even varies day to day for me. It’s becoming a bit of a meme with my friends on how Unreal Engine 5 will perform today when we open it up.