In cascade, using a trail renderer, attached to dummy particles (dummy particles come out of emitter, flow to the ground, trail mimics motion), when “Kill Height” is turned on for the trail (but not the dummy particles, the log will start outputting a trail status (it doesn’t, normally):
[2015.08.12-21.59.44:876][976]LogParticles: Data.OutTriangleCount = 192 vs. SourcePrimCount = 1584
[2015.08.12-21.59.44:876][976]LogParticles: Trail 25 has 16 triangles
[2015.08.12-21.59.44:876][976]LogParticles: Trail 19 has 12 triangles
[2015.08.12-21.59.44:876][976]LogParticles: Trail 27 has 6 triangles
[2015.08.12-21.59.44:876][976]LogParticles: Trail 15 has 20 triangles
[2015.08.12-21.59.44:876][976]LogParticles: Trail 2 has 10 triangles
[2015.08.12-21.59.44:876][976]LogParticles: Trail 18 has 0 triangles
[2015.08.12-21.59.44:876][976]LogParticles: Trail 20 has 4 triangles
[2015.08.12-21.59.44:876][976]LogParticles: Trail 13 has 94 triangles
[2015.08.12-21.59.44:876][976]LogParticles: Trail 16 has 2 triangles
[2015.08.12-21.59.44:876][976]LogParticles: Total 'live' trail count = 9
[2015.08.12-21.59.44:876][976]LogParticles: 164 triangles total (not counting degens)
and then crash:
Unknown exception - code 00000001 (first/second chance not available)
"Assertion failed: TRAIL_EMITTER_IS_HEAD(CurrTrailData->Flags) [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.8\Engine\Source\Runtime\Engine\Private\Particles\ParticleTrail2EmitterInstance.cpp] [Line: 2504] "
UE4Editor_Core!FDebug::AssertFailed() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\core\private\misc\outputdevice.cpp:355] UE4Editor_Engine!FParticleRibbonEmitterInstance::DetermineVertexAndTriangleCount() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\particles\particletrail2emitterinstance.cpp:2511] UE4Editor_Engine!FParticleRibbonEmitterInstance::FillReplayData() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\particles\particletrail2emitterinstance.cpp:2739] UE4Editor_Engine!FParticleRibbonEmitterInstance::GetDynamicData() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\particles\particletrail2emitterinstance.cpp:2589] UE4Editor_Engine!UParticleSystemComponent::CreateDynamicData() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\particles\particlecomponents.cpp:3174] UE4Editor_Engine!UParticleSystemComponent::UpdateDynamicData() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\particles\particlecomponents.cpp:3279] UE4Editor_Engine!UParticleSystemComponent::SendRenderDynamicData_Concurrent() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\particles\particlecomponents.cpp:2899] UE4Editor_Engine!UActorComponent::DoDeferredRenderUpdates_Concurrent() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\components\actorcomponent.cpp:1180] UE4Editor_Engine!UWorld::SendAllEndOfFrameUpdates() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\leveltick.cpp:806] UE4Editor_Engine!UWorld::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\engine\private\leveltick.cpp:1313] UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\unrealed\private\editorengine.cpp:1339] UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\editor\unrealed\private\unrealedengine.cpp:366] UE4Editor!FEngineLoop::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\launchengineloop.cpp:2359] UE4Editor!GuardedMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\launch.cpp:142] UE4Editor!GuardedMainWrapper() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\windows\launchwindows.cpp:126] UE4Editor!WinMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.8\engine\source\runtime\launch\private\windows\launchwindows.cpp:200]