Hi, I am fairly new to UE, I have been learning the engine for a few months now.
I apologize if this is the wrong place for this. It’s my first post to these forums.
Recently, I have been working on a project for the last few weeks now and everything was going smoothly. I am early enough in the project that I was able to switch from UE5.4 to UE5.5, enabled some of the new features like Mega Lights to try them out - and everything was going perfectly fine. But after a few days of work, I suddenly crashed while compiling. I had made a couple changes since my last compile, so I don’t quite know what the exact issue is, but I have tried to resolve this in several different ways, such as reverting some of my files back to an older version I had of them from the week prior, toggling certain settings on and off like raytracing on certain lights, going through the majority of the meshes I’m using to ensure they’re all using the correct settings which they are. I have even gone through and tried turning off Mega Lights for the direct light in the scene, and my Post Process Volumes individually.
The closest I have found is that when I have ray tracing, path tracing, nanite, VSM all turned on in the project settings things work great. But now, when I have those same settings and I enable Mega Lights, I can’t enter PIE without getting this crash report I’ll quote below. If I go into the engine files and disable Mega Lights on the project, everything loads and works fine, but when I enable Mega Lights, I am fine as long as I don’t compile or go into PIE. And after it crashes, it loads the UE5 splash screen just fine, open up the editor, starts to process the shaders, and go through the construction script, etc. but will crash during that process every time. After adding in the debug symbols, the crash report mentions Mega Lights and the Light Function Atlas.
But as far as I know, I don’t use the LFA for any of my lights. The only thing I can think of that might be using it is the word “preview” I see on my lights every now and then, which I’ll admit, I don’t know what causes that or if it’s the problem.
I’ll happily give more info if it’s needed, but I am very curious if anyone else has run into a similar issue so far in 5.5. And if anyone can help fix this, I’d greatly appreciate it!
Thank you.
The crash report text:
Fatal error: [File:D:\build\++UE5\Sync\Engine\Source\Runtime\RenderCore\Private\RenderingThread.cpp] [Line: 863]
Rendering thread exception:
Fatal error!
Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000000000000008
0x00007ff8dc878080 UnrealEditor-Renderer.dll!LightFunctionAtlas::BindGlobalParameters() [D:\build\++UE5\Sync\Engine\Source\Runtime\Renderer\Private\LightFunctionAtlas.cpp:990]
0x00007ff8dcb6ad77 UnrealEditor-Renderer.dll!FDeferredShadingSceneRenderer::RenderMegaLights() [D:\build\++UE5\Sync\Engine\Source\Runtime\Renderer\Private\MegaLights\MegaLights.cpp:1316]
0x00007ff8dc4accb9 UnrealEditor-Renderer.dll!FDeferredShadingSceneRenderer::Render() [D:\build\++UE5\Sync\Engine\Source\Runtime\Renderer\Private\DeferredShadingRenderer.cpp:2845]
0x00007ff8dd284b26 UnrealEditor-Renderer.dll!RenderViewFamilies_RenderThread() [D:\build\++UE5\Sync\Engine\Source\Runtime\Renderer\Private\SceneRendering.cpp:5431]
0x00007ff8dd23bb8a UnrealEditor-Renderer.dll!`UE::RendererPrivateUtils::Implementation::TPersistentBuffer<UE::HLSL::FCellBlockData,UE::RendererPrivateUtils::Implementation::FStructuredBufferTraits>::ValidateGPUData<`FSceneCullingBuilder::UploadToGPU'::`51'::<lambda_1> >'::`12'::<lambda_1>::operator()() [D:\build\++UE5\Sync\Engine\Source\Runtime\Renderer\Private\SceneRendering.cpp:5734]
0x00007ff9609ab7c5 UnrealEditor-RenderCore.dll!`FRenderCommandPipeRegistry::StopRecording'::`2'::<lambda_1>::operator()() [D:\build\++UE5\Sync\Engine\Source\Runtime\RenderCore\Private\RenderingThread.cpp:1541]
0x00007ff9609d94cf UnrealEditor-RenderCore.dll!TGraphTask<TFunctionGraphTaskImpl<void __cdecl(void),1> >::ExecuteTask() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Async\TaskGraphInterfaces.h:634]
0x00007ff93de72722 UnrealEditor-Core.dll!UE::Tasks::Private::FTaskBase::TryExecuteTask() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Tasks\TaskPrivate.h:504]
0x00007ff93de67d4a UnrealEditor-Core.dll!FNamedTaskThread::ProcessTasksNamedThread() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Async\TaskGraph.cpp:779]
0x00007ff93de681ee UnrealEditor-Core.dll!FNamedTaskThread::ProcessTasksUntilQuit() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Async\TaskGraph.cpp:668]
0x00007ff960a07e1c UnrealEditor-RenderCore.dll!RenderingThreadMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\RenderCore\Private\RenderingThread.cpp:317]
0x00007ff960a0ceb4 UnrealEditor-RenderCore.dll!FRenderingThread::Run() [D:\build\++UE5\Sync\Engine\Source\Runtime\RenderCore\Private\RenderingThread.cpp:443]
0x00007ff93e49c0ad UnrealEditor-Core.dll!FRunnableThreadWin::Run() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Windows\WindowsRunnableThread.cpp:159]
0x00007ff93e4935cf UnrealEditor-Core.dll!FRunnableThreadWin::GuardedRun() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Windows\WindowsRunnableThread.cpp:79]
0x00007ff989b17374 KERNEL32.DLL!UnknownFunction []