Noob in unreal engine 5
When I place an emissive light near a metal material, it produces a very noisey picture.
that’s a known limit of lumen. the sampling strategy can not pickup fine grain emissive details. you should put real (“analytical”) lamps in those places to mitigate this limit.
The problem is that I use ray tracing
kinda the same limitation. sampling is limited to keep the performance realtime. on rough surfaces in the range of ~0.1 to 0.4 it will be noizy and temporally unstable in motion. below that you have fully shiny which works and above it use surface cache approximation. it is what it is. performance deals. so… deal with it. design your assets around that.
You can use r.Lumen.Reflections.ScreenSpaceReconstruction.TonemapStrength 1 to cut down on the noise, but the intensity of bright reflections are toned down.
Bright emissive surfaces, especially small ones, are inherently problematic with lumen. Generally it’s best to make them weak, not the primary light source, make them as large as possible, make sure they have distance fields enabled and are well represented in the lumen scene (which can be viewed under “lit”)
There’s also a checkbox on static meshes called emissive light source which will prevent a mesh being used as a light from culling as quickly, making it more stable in the distance.
Also reflections on metallic and/or semi gloss materials tend to be the worst.
I use ray tracing
so do we. and we get the same result.
it’s just how raytracing works, rn. for every pixel that reflects something, every frame a random ray is cast for rough materials and temporally stabilised. casting more rays to gather more of the environment would kill the performance.
make it all shiny, add bumps and grime or lower the specular to get rid of the reflection noise on rough clean materials. that’s how you gotta do it.
No, you don’t understand the topic, I’m talking about how to use Nvidia real time denoiser (there is a special version of the Unreal engine where this denoiser is) I don’t understand how to use the DENOISER, that’s why I’m asking for help!
Here’s a video to see how it works — https://www.youtube.com/watch?v=tjf-1BxpR9c&t=359s
that’s the denoiser for the pathtracer. that’s offline rendering. that’s not for ingame content (yet?). eventually they may implement a clean denoise pass when the hardware gets fast enough for realtime application.
r.Reflections.Denoiser 2 is enabled by default. i dunno rn to what extend it works in raytracing since it’s not under the lumen or raytracing category.
edit: does nothing for raytraced reflections. hmm
and… lemme show you how raytraced reflections looks like without any temporal help
random samples of the environment.
this is argueable an injection point for optix. i reckon it would chew thru that. given enough beef to compute. not easy to generalize the content tho. and you would get ai wobble, cause the noise is some serious randomness every frame.
list this video to 4:34 to 4:48 https://www.youtube.com/watch?v=tjf-1BxpR9c&t
dude. those videos have been rendered at settings i can’t run or know about and mosdef using the pathtracer offline. i dabbled in the raytracing code a lil bit. rt is not my forte, but i get some of the things. i’d like to nuke the random seqeuence too. (like cycles can run without auto seed) to some degree per frame, but that turns into a mess of world coords. and at hit point you still need just a random sample to rough it up, and it’s limited for performance. yo
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