Epic's GPUlightmass

[ElectricNZ]

@PrizmIzm

Thanks for the response, and good to known about the progress, I’m sure other people will want to know about these things. I’ll try and answer the best I can.

1. With CPU Lightmass you can bake a skylight in stationary mode and then adjust it’s own intensity + Indirect Lighting Intensity within a post process volume - that gives the effect of fading in / out a baked daylight scene. There are several limitations to doing this 1. When you fade down ‘Indirect Lighting Intensity’ in the postprocess volume, it fades out the influence of all baked lighting and volumetric light probes in the level - so if you’ve baked any other lights, they’re gone also. 2. This method can only contain one lightbake and not several different ones; so if you wanted to bake a day scene, an evening scene, and a night scene, and fade between them then you’re stuck. 3. CPU Lightmass is hugely inefficient and slow. I personally want to bake lighting for an open world town (indoors and outdoors), but the quickest I can get it down to (without loosing too much quality) is about 3 minutes per building! 4. CPU LM doesn’t allow me to just rebake the area I’m working on, so the idea of re-baking a whole town every time I change a single light is unthinkable.
2. This is VERY encouraging - such a simple fix would save thousands of people, thousands of hours!
3. This is a shame - the most simple system I could think that would cure a lot of woes would use the same probes that are in the editor right now, but just allow the drawing of a simple volume and for there to be a vertical and horizontal density slider which would populate the volume with a grid of probes. Another massive addition would be the ability to darken / lighten those probes after bake - this would allow artists to be able to exclude volumetric fog from indoor areas (another huge feature for a relatively simple change).
4. Awesome! I figured that would be a priority. My GPUs are ready.

Bugs

3. Editor was not compiling and I was using an SLS cubemap (not a captured scene) so there’s no way for me to recapture.

I hope all this helps. I can see real potential here once all your algos are in and the efficiency is up. I was a big fan of your independent GPULM, I’ve used it a lot.

Seconded on point #2

This alone would increase productivity and help scheduling massively.

[Luoshuang]

We’ve just implemented Intel Open Image Denoise for lightmap GI denoising in Dev-Rendering. Denoising in preview is not supported as the latency is very high. However you should be able to get way less noise in baked lightmaps. Still, to get good quality with this brute force renderer you’ll need very high sample counts (16k). The denoiser may be able to reduce that to 512 - 1k though.

[techtuts]

Is it possible to add support for the Two-sided foliage model in lightmass? eg. light scattering through leaves to the area below.
Would be really nice for forest environments

[AE_3DFX]

Probably EPIC knows but just in case. Change log for March 17, 2020 Vulkan 1.2.135 spec update: · KhronosGroup/Vulkan-Docs@18caa8e · GitHub

[maxbrown]

@Luoshuang

We’ve just implemented Intel Open Image Denoise for lightmap GI denoising in Dev-Rendering…However you should be able to get way less noise in baked lightmaps. Still, to get good quality with this brute force renderer you’ll need very high sample counts (16k). The denoiser may be able to reduce that to 512 - 1k though.

Nice! With 1k settings for both sample counts the same project as before (page 1, 4th post) now results in this image. A big visual improvement.

[Nocturness]

@Luoshuang

We’ve just implemented Intel Open Image Denoise for lightmap GI denoising in Dev-Rendering. Denoising in preview is not supported as the latency is very high. However you should be able to get way less noise in baked lightmaps. Still, to get good quality with this brute force renderer you’ll need very high sample counts (16k). The denoiser may be able to reduce that to 512 - 1k though.

compiling… Just realease the kraken

another test without denoiser
https://youtube.com/watch?v=u1c2TonsAzE](https://www.youtube.com/watch?v=u1c2TonsAzE)

[kurylo3d]

This is so awesome. Cant wait until its in an actual build ready to use

Does it handle hlods well? Luoshuangs old one used to not handle those and take the hlods into account into lighting the rest of the envrionment leaving awkward lighting where hlods would intersect.

[Luoshuang]

@kurylo3d

This is so awesome. Cant wait until its in an actual build ready to use

Does it handle hlods well? Luoshuangs old one used to not handle those and take the hlods into account into lighting the rest of the envrionment leaving awkward lighting where hlods would intersect.

HLOD and LODs are not implemented currently, but shouldn’t be very hard on top of the new system (with proper instance management)

[tc22_LEOCHOU (tc22)]

Unreal Engine 4.26 DevRendering Branch / DXR GPU Lightmass first test!

my try in sample 8k…still some noise, any suggestion? do i need re compile dev render again?

[maxbrown]

@tc22 some things I would try to improve quality;

• use 3d geometry you modeled yourself with proper lightmaps in 3dsMax/Maya/Blender
• using higher lightmap sizes
• disabling lightmapp compression in the world settings

[tc22_LEOCHOU (tc22)]

@maxbrown

@tc22 some things I would try to improve quality;

• use 3d geometry you modeled yourself with proper lightmaps in 3dsMax/Maya/Blender
• using higher lightmap sizes
• disabling lightmapp compression in the world settings

Thank you Maxbrown!

i rebuild devrendering again , it seem less noise in viewport!
and add denoise gi option! see attachment!

seem in shadow there still had movement noise , i don’t know why it happen !

[Luoshuang]

Note that when you enable ray tracing, realtime ray traced shadows will be on automatically. You probably want to set r.RayTracing.ForceAllRayTracingEffects=0 to disable all realtime ray tracing effects.

[Chosker]

great work Luoshuang (and the rest of the team), really looking forward to this once it’s released

also it’s great that you’re reacting to feedback on this thread. so a couple of questions from me:

1. will this work on non-RTX cards?
2. any chance the whole thing could work at runtime? thinking of a scenario like building a procedural level and then building static lights, all under a loading screen

[Nocturness]

@Luoshuang
shader compiler is incredibly slow. is it normal or just for me? also visual studio compile takes 3.5 hour(other branchs max takes 1 hour) lol thats need patience work definitely.

rests incredible. denoiser working good. thx for you and your team works.

i will share the results of denoiser with single material.

UE4.26 | DXR GPULightmass with denoiser | devrendering

[KoTbonda]

I beg for help! I have been trying to build ue4 dev-render for a month now. I just can’t solve this problem - the engine has assembled with errors and does not start. can someone know how to solve this? I will be very grateful for any help!

[/SPOILER]

[fear13th]

@KoTbonda

I beg for help! I have been trying to build ue4 dev-render for a month now. I just can’t solve this problem - the engine has assembled with errors and does not start. can someone know how to solve this? I will be very grateful for any help!

[/SPOILER]

Yes, I also faced the same problem in VS2017, decided to use VS2019 (no errors, no warning)

[The_Distiller]

@Luoshuang It’s just a small thing but you could rename “ToggleLightMapPreview” to “r.GPULightmass.ToggleLightMapPreview”. Would be nice to have all the relevant commands in one place.

[Luoshuang]

@The_Distiller

@Luoshuang It’s just a small thing but you could rename “ToggleLightMapPreview” to “r.GPULightmass.ToggleLightMapPreview”. Would be nice to have all the relevant commands in one place.

Well that’s because ToggleLightmapPreview belongs to FStaticLightingSystemInterface - an interface allowing ppl to implement their own lightmap baking system beyond GPULightmass

[The_Distiller]

I see. Thanks for clarifying!

[StefanLukacs]

Hi,
ineed help.
I played last week with dev-rendering build and gpulightmass, worked fine. Now I downloaded the latest one, and it is not working anymore. By “ToggleLightmapPreview” Command I got this error:

Sorry for my bad Englich

Thanks