# Luoshuang's GPULightmass **URL:** \ **Category:** Rendering\ **Tags:** unreal-engine\ **Created:** [April 13, 2018, 5:44am UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474 "2018-04-13T05:44:47Z")\ **Posts on this page:** 20\ **Page:** 49
**Author:** ![Sumsion3D](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Sumsion3D](https://forums.unrealengine.com/u/Sumsion3D)\ **Post date:** [March 16, 2019, 7:01pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1001 "2019-03-16T19:01:12Z")
> [@samdax](#): > > WOW! that’s an amazing work! Can’t wait to have this new version 😃 Has this overhaul happened in the past few months? I can’t find any further mentions. The potential improvements are staggeringly awesome! ---
**Author:** ![Luoshuang](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Luoshuang](https://forums.unrealengine.com/u/Luoshuang)\ **Post date:** [March 16, 2019, 7:20pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1002 "2019-03-16T19:20:51Z")
**Prometheus - GPU Lightmass Overhaul** Lightmap UV Testing 4.22.0 Release: [4.22.0-Release - Orangedox](https://dl.orangedox.com/FQOQDuOwqiVCNvcsnP) **Updated 13:55 2019/3/17** 0.0.1: Fixed some bright corner issues (lol).] **Updated 00:10 2019/3/21** 0.0.4: Fixed chart dilation issue.] **Updated 13:11 2019/3/28** 0.2.0: Greatly improve video memory consumption.] **Updated 14:35 2019/4/04** 0.3.0: Added skylight importance sampling and other parameters.] Needs CUDA driver version \>= 419.17 Since the overhaul took much longer than I expected, I decided to roll out some new versions containing important functionalities to test whether they work well and if I should invest more into them. This version focuses on lightmap UVs and dark corner elimination. **Only a single static skylight is supported, no other lights. Also no masked material support, no VLM/SPLS support. Just testing lightmap UVs.** Creating lightmap UVs for complex objects & dark corners at object intersections are concerning/frustrating issues always. I have been testing multiple (potentially costly) techniques to see whether I can mitigate most of the artifacts - especially at lower lightmap resolution. Now this version should be able to get rid of most of those ‘common’ dark corners, provided that \*\*the hard edges on your object are properly split - which most auto UV gen software would do \*\*(Due to limitations in UE4’s lightmap directionality representation, ‘spherical harmonics’, non-planar texels won’t work well even if Prometheus has computed them super precisely, which means lightmap texels crossing a hard edge will never be correct). Baked with Prometheus: ![1.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/3X/f/5/f591824c2f3a4112ab55818f08866ce795b68abf.jpeg) ![2.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/3X/a/c/ac55e48c5ef59eb04678faaaa4e2a5e3db9508c2.jpeg) V-Ray viewport reference (Reinhard tonemapping, exposure +3) ![3.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/3X/f/a/fa0b20cd1ab4e9bf8e2a5447a5c38f0f90d71fb7.jpeg) ---
**Author:** ![anonymous\_user\_888c5283](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_888c5283](https://forums.unrealengine.com/u/anonymous_user_888c5283)\ **Post date:** [March 17, 2019, 1:54am UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1003 "2019-03-17T01:54:32Z")
> [@](#): > > **You can use command line to launch the editor and bake lighting to save GPU resources for GPULightmass, especially video memory.** > > - Engine/Binaries/Win64/UE4Editor-Cmd.exe “path o\your\project\yourproject.uproject” -run=resavepackages -buildlighting -allowcommandletrendering -map=/Game/Maps/MyMap.umap > - Remember to replace Content with Game in the umap path What about [Build lighting from command line - Rendering - Epic Developer Community Forums](https://answers.unrealengine.com/questions/124936/build-lighting-from-command-line.html) ? … says can’t be absolute path … not to include “folders” ---
**Author:** ![nguyenthiet](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@nguyenthiet](https://forums.unrealengine.com/u/nguyenthiet)\ **Post date:** [March 17, 2019, 7:00am UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1004 "2019-03-17T07:00:27Z")
> [@Muchasty](#): > > GPU Lightmass (4.19.1) causes some problems with this scene ( dark upper area and some sparks on the ceiling ): > > [https://forums.unrealengine.com/filedata/fetch?filedataid=135603&type=thumb](https://forums.unrealengine.com/filedata/fetch?filedataid=135603&type=thumb) > > Below the reference CPU baked (4.18.3): > > [https://forums.unrealengine.com/filedata/fetch?filedataid=135604&type=thumb](https://forums.unrealengine.com/filedata/fetch?filedataid=135604&type=thumb) me too, I have this problem and i can not fix this, can you help me,please ---
**Author:** ![PMcKenzie2004](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@PMcKenzie2004](https://forums.unrealengine.com/u/PMcKenzie2004)\ **Post date:** [March 17, 2019, 5:37pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1005 "2019-03-17T17:37:17Z")
Thanks, I will test this version of GPU Lightmass ASAP and compare results to the past versions. ---
**Author:** ![anonymous\_user\_21e38222](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_21e38222](https://forums.unrealengine.com/u/anonymous_user_21e38222)\ **Post date:** [March 17, 2019, 9:01pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1006 "2019-03-17T21:01:04Z")
Hey ! Got this error on a clean engine with Prometheus 0.0.1, any idea what could be the cause of it ? Looks like a dll mismatch. https://i.imgur.com/eHGZQkE.png ---
**Author:** ![Luoshuang](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Luoshuang](https://forums.unrealengine.com/u/Luoshuang)\ **Post date:** [March 17, 2019, 9:24pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1007 "2019-03-17T21:24:33Z")
> [@LegendreVR](#): > > Hey ! Got this error on a clean engine with Prometheus 0.0.1, any idea what could be the cause of it ? Looks like a dll mismatch. I’ve updated a fresh packaged version, you can try again ---
**Author:** ![anonymous\_user\_21e38222](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_21e38222](https://forums.unrealengine.com/u/anonymous_user_21e38222)\ **Post date:** [March 17, 2019, 10:15pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1008 "2019-03-17T22:15:06Z")
> [@](#): > > I’ve updated a fresh packaged version, you can try again Good now, thanks for the quick patch ! Looking forward to a day of testing tomorrow 🙂 ---
**Author:** ![Sotet\_Farkas](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Sotet\_Farkas](https://forums.unrealengine.com/u/Sotet_Farkas)\ **Post date:** [March 18, 2019, 6:46pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1009 "2019-03-18T18:46:48Z")
This is amazing. you are awesome. It is possible that in the future this will work for AMD, I was thinking about buying a vega 7 ---
**Author:** ![ldo](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@ldo](https://forums.unrealengine.com/u/ldo)\ **Post date:** [March 18, 2019, 9:38pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1010 "2019-03-18T21:38:17Z")
Hi \*\*\*\*, I am testing your new Prometheus and getting some problems. On the first pic white dots, and on the second dot it is too noisy (how can I switch settings to max quality?) I found this lines in code : [DevOptions.GPULightmass] NumPrimaryGISamples=32 NumSecondaryGISamples=16 FireflyClampingThreshold=10.0 Which numbers I need for Ultimate settings like in previous ver. of GPU Lightmass ? ---
**Author:** ![Luoshuang](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Luoshuang](https://forums.unrealengine.com/u/Luoshuang)\ **Post date:** [March 18, 2019, 9:51pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1011 "2019-03-18T21:51:34Z")
> [@ldo](#): > > Hi \*\*\*\*, > > I am testing your new Prometheus and getting some problems. On the first pic white dots, and on the second dot it is too noisy (how can I switch settings to max quality?) > > I found this lines in code : > > [DevOptions.GPULightmass] > NumPrimaryGISamples=32 > NumSecondaryGISamples=16 > FireflyClampingThreshold=10.0 > > Which numbers I need for Ultimate settings like in previous ver. of GPU Lightmass ? Prometheus currently does not respect num samples settings :(. Its main purpose is to test dark corner elimination and UV robustness. Did you get problems from them? ---
**Author:** ![ldo](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@ldo](https://forums.unrealengine.com/u/ldo)\ **Post date:** [March 18, 2019, 10:01pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1012 "2019-03-18T22:01:54Z")
> [@](#): > > Prometheus currently does not respect num samples settings :(. Its main purpose is to test dark corner elimination and UV robustness. Did you get problems from them? Yep, just tried 128/32, nothings changed. No I didn’t investigate for dark corner elimination and UV problems yet, but I’ll do it. Now I know that this version is just for testing, so I will ignore all this artifacts… Thank you. Any ETA for final release? ---
**Author:** ![scha](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/scha/32/1135430_2.png) [@scha](https://forums.unrealengine.com/u/scha)\ **Post date:** [March 19, 2019, 1:43pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1013 "2019-03-19T13:43:36Z")
Does it work with old GPUs (GTX670)? I try to use it with 4.22.1 and I run into “invalid device symbol” error then crash. I used the automatic installer. (Sorry if that was asked before) ---
**Author:** ![Xivader](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/xivader/32/568978_2.png) [@Xivader](https://forums.unrealengine.com/u/Xivader)\ **Post date:** [March 19, 2019, 1:48pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1014 "2019-03-19T13:48:39Z")
> [@scha](#): > > Does it work with old GPUs (GTX670)? I try to use it with 4.22.1 and I run into “invalid device symbol” error then crash. I used the automatic installer. (Sorry if that was asked before) Same here with GTX 650. ---
**Author:** ![SilverDragon](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@SilverDragon](https://forums.unrealengine.com/u/SilverDragon)\ **Post date:** [March 19, 2019, 10:36pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1015 "2019-03-19T22:36:32Z")
Are multiple GPUs supported? Also, is it possible to use different GPUs, like none SLI setups, for example a bunch of 1060, since the heavy process is on the memory this can probably improve times keeping the scaling costs low. ---
**Author:** ![PMcKenzie2004](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@PMcKenzie2004](https://forums.unrealengine.com/u/PMcKenzie2004)\ **Post date:** [March 19, 2019, 11:10pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1016 "2019-03-19T23:10:13Z")
> [@](#): > > Prometheus currently does not respect num samples settings :(. Its main purpose is to test dark corner elimination and UV robustness. Did you get problems from them? I got the following results. Sketchup to 4.21 via Datasmith. Upgrade project to 4.22 preview 5. Bake with Prometheus. Thoughts? ---
**Author:** ![nachovillegas](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@nachovillegas](https://forums.unrealengine.com/u/nachovillegas)\ **Post date:** [March 20, 2019, 10:44am UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1017 "2019-03-20T10:44:42Z")
Hi to all, First of all thank you for this trick. I am having the issue of very low performance of de GPU running at 5-6%. Graphic card: 1060 6gb, drivers updated. Anyone know how to improve it? Thank you in advance. ---
**Author:** ![Luoshuang](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Luoshuang](https://forums.unrealengine.com/u/Luoshuang)\ **Post date:** [March 20, 2019, 6:18pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1018 "2019-03-20T18:18:26Z")
> [@scha](#): > > Does it work with old GPUs (GTX670)? I try to use it with 4.22.1 and I run into “invalid device symbol” error then crash. I used the automatic installer. (Sorry if that was asked before) The card needs to support SM 3.5, which means at least 7XX series > [@SilverDragon](#): > > Are multiple GPUs supported? > > Also, is it possible to use different GPUs, like none SLI setups, for example a bunch of 1060, since the heavy process is on the memory this can probably improve times keeping the scaling costs low. No multi GPU support currently ☹ > [@nachovillegas](#): > > Hi to all, > > First of all thank you for this trick. > > I am having the issue of very low performance of de GPU running at 5-6%. > > Graphic card: 1060 6gb, drivers updated. > > Anyone know how to improve it? > > Thank you in advance. If you’re on Win10, select this queue type and see whether it is fully utilized: ![-20190320-141649.png](https://d3kjluh73b9h9o.cloudfront.net/original/3X/f/5/f569bc1a708206cbedefe58dad2106e55b4a0024.png) Starting from NVIDIA 419.xx drivers, how the CUDA and 3D queue are scheduled is changed and 3D will always take priority over CUDA. ---
**Author:** ![Luoshuang](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Luoshuang](https://forums.unrealengine.com/u/Luoshuang)\ **Post date:** [March 20, 2019, 6:20pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1019 "2019-03-20T18:20:45Z")
> [@PMcKenzie2004](#): > > I got the following results. Sketchup to 4.21 via Datasmith. Upgrade project to 4.22 preview 5. Bake with Prometheus. Thoughts? Looks no problem to me 🙂 Are you having any issue with complex objects? One thing I want to achieve with Prometheus is that it should work with auto gen UVs (not generated by UE4Editor, but by your modeling software, like ‘auto projection/layout’ in Maya) without producing artifacts beyond UV seams (which is supposed to be addressed in following releases) so that lightmap UV workflow can be simplified greatly. ---
**Author:** ![PMcKenzie2004](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@PMcKenzie2004](https://forums.unrealengine.com/u/PMcKenzie2004)\ **Post date:** [March 20, 2019, 11:50pm UTC](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474/1020 "2019-03-20T23:50:50Z")
> [@](#): > > Looks no problem to me 🙂 Are you having any issue with complex objects? One thing I want to achieve with Prometheus is that it should work with auto gen UVs (not generated by UE4Editor, but by your modeling software, like ‘auto projection/layout’ in Maya) without producing artifacts beyond UV seams (which is supposed to be addressed in following releases) so that lightmap UV workflow can be simplified greatly. I’m good with it :). I will try something more complex (irregular sculpture perhaps) this weekend and report back. Thank you for your continued work on this! [Previous page](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474.md?page=48) [Next page](https://forums.unrealengine.com/t/luoshuangs-gpulightmass/109474.md?page=50)