Yes 15 PC´s today 
Will give it a try, thanks. The lightmap build is currently being calculated at “Extreme” quality…
Clear your cache from within swarm agent on the offending PC (Cache -> Clean, then Cache -> Validate). Might have to do it on all build PCs to be safe. This happens to us when we build different projects with different UE4 versions without clearing cache in between.
Did you try with 4.22.2?
I’m having problem building lightmass in 4.22.2 It crashes when “building reflection captures”
and this is the log:
[2019.05.29-09.36.33:369][443]LogWindows: Windows GetLastError: Operazione completata. (0)
[2019.05.29-09.36.33:369][443]LogThreadingWindows: Error: Runnable thread RenderThread 2 crashed.
[2019.05.29-09.36.33:369][443]LogWindows: Error: === Critical error: ===
[2019.05.29-09.36.33:369][443]LogWindows: Error:
[2019.05.29-09.36.33:369][443]LogWindows: Error: Fatal error: [File:C:\Users\LKA-Bomba\Documents\MID\LKA-UE4.22\Engine\Source\Runtime\RenderCore\Private\RenderingThread.cpp] [Line: 819]
[2019.05.29-09.36.33:369][443]LogWindows: Error: Rendering thread exception:
[2019.05.29-09.36.33:369][443]LogWindows: Error: Fatal error!
[2019.05.29-09.36.33:369][443]LogWindows: Error:
[2019.05.29-09.36.33:369][443]LogWindows: Error: Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0xffffffff
[2019.05.29-09.36.33:369][443]LogWindows: Error:
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa35cea293 UE4Editor-D3D11RHI.dll!FD3D11DynamicRHI::RHISetShaderUniformBuffer() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\windows\d3d11rhi\private\d3d11commands.cpp:717]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa4a6ee8e0 UE4Editor-RHI.dll!FRHICommandListExecutor::ExecuteInner_DoExecute() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\rhi\private\rhicommandlist.cpp:325]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa4a6ee4c4 UE4Editor-RHI.dll!FRHICommandListExecutor::ExecuteInner() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\rhi\private\rhicommandlist.cpp:592]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa4a6eeed6 UE4Editor-RHI.dll!FRHICommandListExecutor::ExecuteList() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\rhi\private\rhicommandlist.cpp:615]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa4a6c8a87 UE4Editor-RHI.dll!FRHICommandListBase::~FRHICommandListBase() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\rhi\private\rhicommandlist.cpp:846]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa4a6eaf9f UE4Editor-RHI.dll!FRHICommandWaitForAndSubmitSubList::Execute() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\rhi\private\rhicommandlist.cpp:1041]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa4a6ecec7 UE4Editor-RHI.dll!FRHICommand<FRHICommandWaitForAndSubmitSubList>::ExecuteAndDestruct() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\rhi\public\rhicommandlist.h:680]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa4a6ee8e0 UE4Editor-RHI.dll!FRHICommandListExecutor::ExecuteInner_DoExecute() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\rhi\private\rhicommandlist.cpp:325]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa4a6ee4c4 UE4Editor-RHI.dll!FRHICommandListExecutor::ExecuteInner() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\rhi\private\rhicommandlist.cpp:592]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa4a6ef444 UE4Editor-RHI.dll!FRHICommandListExecutor::ExecuteList() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\rhi\private\rhicommandlist.cpp:642]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa4a7005da UE4Editor-RHI.dll!FDynamicRHI::LockVertexBuffer_RenderThread() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\rhi\private\rhicommandlist.cpp:1979]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa39541dba UE4Editor-Renderer.dll!FParallelMeshDrawCommandPass:ispatchDraw() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\renderer\private\meshdrawcommands.cpp:1230]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa3950ffde UE4Editor-Renderer.dll!SubmitDistortionMeshDrawCommands() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\renderer\private\distortionrendering.cpp:511]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa394f2a66 UE4Editor-Renderer.dll!FSceneRenderer::RenderDistortion() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\renderer\private\distortionrendering.cpp:640]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa394a1fe7 UE4Editor-Renderer.dll!FDeferredShadingSceneRenderer::Render() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\renderer\private\deferredshadingrenderer.cpp:1924]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa3984b370 UE4Editor-Renderer.dll!CaptureSceneToScratchCubemap() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\renderer\private\reflectionenvironmentcapture.cpp:731]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa3985af16 UE4Editor-Renderer.dll!TGraphTask<TEnqueueUniqueRenderCommandType<`CaptureSceneIntoScratchCubemap'::`4'::CaptureCommandName,<lambda_0b438a0ab9eba0ac7600a08d0c609e3c> > >::ExecuteTask() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\core\public\async askgraphinterfaces.h:842]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa43dc22d8 UE4Editor-Core.dll!FNamedTaskThread::ProcessTasksNamedThread() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\core\private\async askgraph.cpp:686]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa43dc2563 UE4Editor-Core.dll!FNamedTaskThread::ProcessTasksUntilQuit() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\core\private\async askgraph.cpp:582]
[2019.05.29-09.36.33:369][443]LogWindows: Error: [Callstack] 0x00007ffa4a8459f1 UE4Editor-RenderCore.dll!RenderingThreadMain() [c:\users\lka-bomba\doc
[2019.05.29-09.36.33:369][443]LogWindows: Error:
[2019.05.29-09.36.33:369][443]LogWindows: Error:
[2019.05.29-09.36.33:369][443]LogWindows: Error: Crash in runnable thread RenderThread 2
[2019.05.29-09.36.33:376][443]LogOutputDevice: Warning:
Script Stack (0 frames):
[2019.05.29-09.36.33:376][443]LogWindows: Windows GetLastError: Operazione completata. (0)
[2019.05.29-09.36.33:376][443]LogWindows: Error: HandleError re-entered.
[2019.05.29-09.36.33:376][443]LogWindows: FPlatformMisc::RequestExit(1)
[2019.05.29-09.36.33:388][443]Log file closed, 05/29/19 11:36:33
If I remove any reflection capture in the scene i get this error instead:
LoginId:a4c1de9a4bb6833c0b7be9a44f231422
EpicAccountId:d37d2c3a30454e04b59de72af716f364
Assertion failed: LCI->GetResourceCluster()->UniformBuffer [File:C:\Users\LKA-Bomba\Documents\MID\LKA-UE4.22\Engine\Source\Runtime\Renderer\Private\LightMapRendering.cpp] [Line: 49]
UE4Editor_Core!FWindowsErrorOutputDevice::Serialize() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\core\private\windows\windowserroroutputdevice.cpp:79]
UE4Editor_Core!FOutputDevice::LogfImpl() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\core\private\misc\outputdevice.cpp:71]
UE4Editor_Core!FDebug::AssertFailed() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\core\private\misc\assertionmacros.cpp:440]
UE4Editor_Core!FDebug::CheckVerifyFailedImpl() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\core\private\misc\assertionmacros.cpp:418]
UE4Editor_Renderer!FUniformLightMapPolicy::GetVertexShaderBindings() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\renderer\private\lightmaprendering.cpp:122]
UE4Editor_Renderer!FMeshPassProcessor::BuildMeshDrawCommands<TMeshProcessorShaders<TBasePassVertexShaderPolicyParamType<FUniformLightMapPolicy>,FBaseHS,FBaseDS,TBasePassPixelShaderPolicyParamType<FUniformLightMapPolicy>,FMeshMaterialShader,FMeshMaterialShade() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\renderer\public\meshpassprocessor.inl:64]
UE4Editor_Renderer!FBasePassMeshProcessor::Process<FUniformLightMapPolicy>() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\renderer\private\basepassrendering.cpp:970]
UE4Editor_Renderer!FBasePassMeshProcessor::AddMeshBatch() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\renderer\private\basepassrendering.cpp:1504]
UE4Editor_Renderer!GenerateDynamicMeshDrawCommands() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\renderer\private\meshdrawcommands.cpp:516]
UE4Editor_Renderer!FMeshDrawCommandPassSetupTask::AnyThreadTask() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\renderer\private\meshdrawcommands.cpp:791]
UE4Editor_Renderer!TGraphTask<FMeshDrawCommandPassSetupTask>::ExecuteTask() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\core\public\async askgraphinterfaces.h:842]
UE4Editor_Core!FTaskThreadAnyThread::ProcessTasks() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\core\private\async askgraph.cpp:1029]
UE4Editor_Core!FTaskThreadAnyThread::ProcessTasksUntilQuit() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\core\private\async askgraph.cpp:854]
UE4Editor_Core!FTaskThreadAnyThread::Run() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\core\private\async askgraph.cpp:930]
UE4Editor_Core!FRunnableThreadWin::Run() [c:\users\lka-bomba\documents\mid\lka-ue4.22\engine\source\runtime\core\private\windows\windowsrunnablethread.cpp:96]
For source builds, can we use the 4.21 “EngineModification” files for 4.22 or do we need to manually change some lines in 4.22?
Hi ,
Today, after a lot using your marvelous tool, I have seen that from World Settings, the Indirect Lighting Quality also affects the calculation (recommended to set it to 100). Maybe you already knew this, but I thought it was affected only by the phrase of the first post:
Lightmass parameters and quality settings specified in the editor are ignored except for Num Indirect Lighting Bounces
In addition, what would you think about adding info about Elapsed Time? Even a button to close it after finished, so I can leave it calculating and, when turned back, see the time it took to render it 
Best regards! And Thank you as always!
Anyone know the above? Seems like people are using this with 4.22 but not sure if they’re launcher version or source builds…
whoa this looks amazing.
however I’m gonna wait until it works with 4.22.2 as some people are reporting some errors
can’t wait to try it
Hi, I’m .
I have open sourced GPULightmass here:
With the development of an official GPU Lightmass using DXR starting, GPULightmass is in a frozen state now. Its life is up to you community members!
@YujiangW, big fan of your work!
Is there a release date, or projected UE4 version, for the DXR Lightmass you’re building?
How can I help?
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 and related stuff.
You gave us completely new quality and speed of baking !
THANK YOU !
It would be nice to know what the future is coming with:
- 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 ?
- Is there possibility that DXRLM will be able to use RTX family RT cores to create instant lightmaps, on the fly ?
- Are any changes planned in usage/creation of UV maps dedicated for lightmaps when DXRLM will be released?
- 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! 
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”