REPRO STEPS:
RESULT:
Editor crashes.
Assertion failed: SoftVertices.Num() == 0 || SoftVertices.Num() == NumVertices [File:E:\UE4_Release-413\Engine\Source\Runtime\Engine\Public\SkeletalMeshTypes.h] [Line: 406] UE4Editor_Engine!FSkeletalMeshSceneProxy::GetDynamicElementsSection() skeletalmesh.cpp:5301 UE4Editor_Engine!FSkeletalMeshSceneProxy::GetMeshElementsConditionallySelectable() skeletalmesh.cpp:5123 UE4Editor_Engine!FSkeletalMeshSceneProxy::GetDynamicMeshElements() skeletalmesh.cpp:5068 UE4Editor_Renderer!FSceneRenderer::GatherDynamicMeshElements() scenevisibility.cpp:1895 UE4Editor_Renderer!FSceneRenderer::ComputeViewVisibility() scenevisibility.cpp:2561 UE4Editor_Renderer!FDeferredShadingSceneRenderer::InitViews() scenevisibility.cpp:2795 UE4Editor_Renderer!FDeferredShadingSceneRenderer::Render() deferredshadingrenderer.cpp:571 UE4Editor_Renderer!RenderViewFamily_RenderThread() scenerendering.cpp:1849 UE4Editor_Renderer!TGraphTask<`FRendererModule::BeginRenderingViewFamily'::`21'::EURCMacro_FDrawSceneCommand>::ExecuteTask() taskgraphinterfaces.h:868 UE4Editor_Core!FNamedTaskThread::ProcessTasksNamedThread() taskgraph.cpp:932 UE4Editor_Core!FNamedTaskThread::ProcessTasksUntilQuit() taskgraph.cpp:679 UE4Editor_RenderCore!RenderingThreadMain() renderingthread.cpp:319 UE4Editor_RenderCore!FRenderingThread::Run() renderingthread.cpp:440 UE4Editor_Core!FRunnableThreadWin::Run() windowsrunnablethread.cpp:74
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-34288 in the post.