Crash on play if a BP manipulates a InstancedStaticMeshComponent by using a ClearInstances node followed by an AddInstance node.
This is a blocker for the licensee.
This is a regression:
Working in 4.16.2-35114769
Not working in 4.17.0 Preview 1-3528061
Crash reporter: [Link Removed]
Crash reporter callstack links to [Link Removed] as well (https://jira.it.epicgames.net/browse/UE-46263); however, the repo in this JIRA will reproduce after the fix for [Link Removed] went in.
Licensee Description:
We noticed a 100% render thread crash (Unknown RHI vertex element type) since we upgrade to 4.17 preview 1
The crash is caused by ClearInstances followed by AddInstance on the InstancedStaticMeshComponent.
I've attached a sample project so you can investigate.
Currently this is a blocker for us so please advise how to fix it, thanks!
Results: The editor will crash immediately on play
LoginId:a1be990b4855275a6b8acdb5d49d864a EpicAccountId:75f47e038a8442f0af6c18e1f38eeb85 Fatal error: [File:D:\Build\++UE4+Release-4.17+Compile\Sync\Engine\Source\Runtime\Windows\D3D11RHI\Private\D3D11VertexDeclaration.cpp] [Line: 49] Unknown RHI vertex element type 0 UE4Editor_Core!FDebug::AssertFailed() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:349] UE4Editor_D3D11RHI!FD3D11VertexDeclarationKey::FD3D11VertexDeclarationKey() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\windows\d3d11rhi\private\d3d11vertexdeclaration.cpp:53] UE4Editor_D3D11RHI!FD3D11DynamicRHI::RHICreateVertexDeclaration() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\windows\d3d11rhi\private\d3d11vertexdeclaration.cpp:97] UE4Editor_RHI!FDynamicRHI::CreateVertexDeclaration_RenderThread() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\rhi\private\rhicommandlist.cpp:1972] UE4Editor_RHI!FRHICommandListImmediate::CreateVertexDeclaration() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\rhi\public\rhicommandlist.h:2626] UE4Editor_ShaderCore!RHICreateVertexDeclaration() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\rhi\public\rhicommandlist.h:3503] UE4Editor_ShaderCore!FVertexFactory::InitDeclaration() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\shadercore\private\vertexfactory.cpp:301] UE4Editor_Engine!FInstancedStaticMeshVertexFactory::InitRHI() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\instancedstaticmesh.cpp:449] UE4Editor_RenderCore!FRenderResource::InitResource() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\rendercore\private\renderresource.cpp:33] UE4Editor_RenderCore!TGraphTask<`BeginInitResource'::`2'::EURCMacro_InitCommand>::ExecuteTask() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\core\public\async\taskgraphinterfaces.h:784] UE4Editor_Core!FNamedTaskThread::ProcessTasksNamedThread() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:650] UE4Editor_Core!FNamedTaskThread::ProcessTasksUntilQuit() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:559] UE4Editor_RenderCore!RenderingThreadMain() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\rendercore\private\renderingthread.cpp:325] UE4Editor_RenderCore!FRenderingThread::Run() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\rendercore\private\renderingthread.cpp:459] UE4Editor_Core!FRunnableThreadWin::Run() [d:\build\++ue4+release-4.17+compile\sync\engine\source\runtime\core\private\windows\windowsrunnablethread.cpp:76]
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-47607 in the post.