Luoshuang's GPULightmass

Man, I just found out about this plugin and wanted to give it a try but I’m on 4.22.2 now. is it possible to use this with 4.22.2?

Hi @YujiangW !
Thanks for your commitment in Lightmass project.
You did sth very, very important. Something extraordinary! Especially for all of us who are using UE4 for ArchViz and related stuff.
You gave us completely new quality and speed of baking !
THANK YOU Yujiang ‘Luoshuang’ Wang !

It would be nice to know what the future is coming with:

  1. If work on current GPULM is frozen does it mean that in next UE4 release (4.23) we should expect built-in GPULM-DXR ( I will call it DXRLM) version ?
  2. Is there possibility that DXRLM will be able to use RTX family RT cores to create instant lightmaps, on the fly ?
  3. Are any changes planned in usage/creation of UV maps dedicated for lightmaps when DXRLM will be released?
  4. What really should we expect from DXRLM ?

I know that you cannot give us answers to all of the questions so I invite to our Ligthmass community @Amanda.Bott , because Lightmass is a critical element in our workflow.
Thank you.

Many thanks for your effort! :smiley:

Any news on Prometheus LM?? It was announced couple month ago and even test version works perfect. Does your statement meat that Prometheus is frozen too?

any news on LOD/HLOD support so we dont see black spots

I haven’t done anything too crazy with it, but it works for me in my custom 4.22.2 source build using the “4.22.0 Unified Settings” download from the OP.

that sounds cool, but honestly I don’t know a thing about all this open source stuff, so you lost me at “custom 4.22.2 source build” I know how to download executables and install them, lol.
could you point directions on how to get this working?

Hey Fael097,

just download the zip for the 4.22! unzip it! put unzipped files in to your UE_4.22 folder. Usually C:\Program Files\Epic Games\UE_4.22.
and you are good to go

Working on 4.22.2 using

I´m using 4.22.2 and works perfect. You can try using the script “Lightmass Configurator”

Hi 'Luoshuang. First thing, i’m brand new in UE since 3 weeks now. And i must say i’m TRULY amazed with your job.

Hopefully this GPU solver will be part of UE sometime soon.

In the meawhile: Can it be possible to add a post Optix (or other kind of solution) denoiser? That would absolutely amazing.

Thanks in advance.
Alex Roman

ohhh interesting. I assume I should backup the files I’m replacing?

ok, I just tried it. a scene that took me 11 hours on cpu just took 3 minutes on gpu. so either my current settings are not being used or this is some sort of witchery lol. also, my quality doesn’t improve much by changing ligthmass settings in world settings. and I’m getting a lot of fireflies. how exactly do I change the quality settings?
edit: nevermind see below

that’s cool, where can I get this script?
edit: ok just found it as lightmass configuration in this thread. gonna try it! cheers
edit2: I downloaded the configurator and rendered the same scene that took 3 minutes before, but on highest quality possible this time. it now took little less than 1 hour but the result is much better than cpu, I cannot believe how amazing this is. definitely a game changer, can’t say how impressed I am. kudos!

so, does changing lightmass settings in my world settings still do anything, or I need to do it via the configurator? how about the buld lighting quality? both don’t seem to do much from what I’m testing.

but most importantly, how about volumetric lightmap detail cell size? I tried different values and they do have some effect, but my dynamic objects look different from cpu volumetric lighting, as if they have some shadows creeping in from underneath. do I still adjust it in the world settings panel or do I have to set it on a config file?

Nice to see you here Master! We hope to appreciate your work on UE4 soon!

Thanks, Mr. Luoshuang’s a lot for your great and useful tool! :slight_smile:
It makes really more realistic look (IMHO) and much faster (even 1060 vs my old 3570k))

But comparing both cpu and gpu render I noticed some dark line under ceiling. Not sure if its good/photoreal? How can I remove it? Maybe more some indirect bounces?

use a different skylight to the flat.

Hey VadoZe,

Is your AO enabled or disabled?


Thank you!! :cool:

My first attempt with Loushuang method. Don’t be severe… just a lighting study. Next step: materials, shaders & fog ;))


Ps. Some UVW Unwrap errors still…

Hello Alex @3Seventh … Nice to see you here !

This what I could recommend you to pay attention are:

  • UV unwrap for Lightmaps to avoid bad shadowing on complex elements - I see many artefacts in your scene
  • and BaseLightmass.ini setup to avoid strange splotches on walls
    I suggest to use:
    Remember that when you upgrade the engine new version (not hotfix release) then you have to change the BaseLigthmass.ini again.

I recommend also to avoid point lights very near some high reflective metallic elements ( like reflectors in lamps GU10 type for example ) cause the you will get some splotches too and probably you should increase the Num params, but it cost a lot of extra bake time.

Thank you Thomasz! Yep, i used a 3dsmax script to unwrap evry single object, but, of course, there were some errors as you can see. And yes, i usually use these settings but i got lazy on this and i think it was something like:


Will be more patient next time :rolleyes:


i dont know when we can get rid of this lightmap creation in ue4 :mad::mad::mad:
its old Technic and take our time

i hope baking in dxr dont depend on lightmaps !!!