Crash in play mode / Sequence render

I creating a scene that’s been rendering fine. Now it crashes. When i remove the Cesium actors, it render and plays.

here’s what the “CrashContext.runtime-xml” reads:
UnrealEditor-CesiumRuntime 0x00007ffa01a60000 + 30d4e UnrealEditor-CesiumRuntime 0x00007ffa01a60000 + 7cbf6 UnrealEditor-Engine 0x00007ffa26460000 + 444fef UnrealEditor-Engine 0x00007ffa26460000 + 223cae2 UnrealEditor-Engine 0x00007ffa26460000 + d79d11 UnrealEditor-Engine 0x00007ffa26460000 + 2166298 UnrealEditor-Engine 0x00007ffa26460000 + d345d5 UnrealEditor-UnrealEd 0x00007ffa348b0000 + b19918 UnrealEditor-UnrealEd 0x00007ffa348b0000 + b4ece6 UnrealEditor-UnrealEd 0x00007ffa348b0000 + b1a3c2 UnrealEditor-UnrealEd 0x00007ffa348b0000 + b6d4aa UnrealEditor-DisplayClusterEditor 0x00007ff9f6fe0000 + 38a7 UnrealEditor-UnrealEd 0x00007ffa348b0000 + b70cb7 UnrealEditor-UnrealEd 0x00007ffa348b0000 + b705a1 UnrealEditor-UnrealEd 0x00007ffa348b0000 + 50dcf3 UnrealEditor-UnrealEd 0x00007ffa348b0000 + e9aac6 UnrealEditor-DisplayClusterEditor 0x00007ff9f6fe0000 + 3c1d UnrealEditor 0x00007ff7eddd0000 + 82f6 UnrealEditor 0x00007ff7eddd0000 + 20d9c UnrealEditor 0x00007ff7eddd0000 + 20e8a UnrealEditor 0x00007ff7eddd0000 + 23c4d UnrealEditor 0x00007ff7eddd0000 + 35564 UnrealEditor 0x00007ff7eddd0000 + 38736 KERNEL32 0x00007ffab8710000 + 17034 ntdll 0x00007ffab9ff0000 + 52651

not sure how to diagnose the problem. any suggestions? id appreciate the help. i can furnish any other data if needed.

Unreal 5.0.3. plugins are all up to date. RTX 3090

You don’t seem to have any debug symbols, so the call stack doesn’t have much information. But the presence of “DisplayClusterEditor” implies you might be using the nDisplay plugin. We’ve previously seen some incompatibilities with that - due to that plugin and the Cesium one using similar third-party libraries, but different versions of them - so it may be worth trying to disable that plugin and see if it helps.


okay…I deactivated the ndisplay plugin, which I’m not sure why it was even on. However, now my project file crashes when I attempt to open it! Not good. anyway I can reactivate the plugin so I can open my project file?

Fatal error: [File:D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp] [Line: 4221] Failed to load UnrealEd Engine class ‘/Script/DisplayClusterEditor.DisplayClusterEditorEngine’.

i was able to recover the project through perforce, but I had to reactivate the nDisplay plugin to get it to work… Unfortunately, this puts me back t square one. Anyway I can deactivate nDisplay without crashing the project crashing ? Any help on this would be appreciated.

I tried enabling the nDisplay plugin and capturing a movie with the sequencer in 5.0.3, and it seemed to work ok, so I’m not sure yet what might be going wrong for you.

Which version of the Cesium for Unreal plugin are you using? Do you have this problem with the Cesium for Unreal Samples project as well, or only with your own project? What platform are you on? Can you install the Unreal Engine debug symbols so that we get a more useful call stack?


It was working earlier in the project. My scene is getting quite large.

I did try to use the virtual camera with the iphone using the unreal remote app. However, that was just to quick test and I’ve uninstalled the plugins.

I’m on Windows. rtx 3090, 24GB VrAM 12GB RAM, Threadripper 3970x.

I enabled debug symbols:
is this what you’re looking for?

Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000000000000250

UnrealEditor_CesiumRuntime!TArray<TScriptDelegate,TSizedDefaultAllocator<32> >::RemoveAllSwap<<lambda_91e272c2e6003ae2685cd0d06095ff3e> >() [D:\RocketSync\5.0.0-19505902+++UE5+Release-5.0\Working\Engine\Source\Runtime\Core\Public\Containers\Array.h:2456]
UnrealEditor_CesiumRuntime!ACesium3DTileset::BeginPlay() [D:\build\U5M-Marketplace\Sync\LocalBuilds\PluginTemp\HostProject\Plugins\CesiumForUnreal\Source\CesiumRuntime\Private\Cesium3DTileset.cpp:473]
UnrealEditor_Engine!AActor::DispatchBeginPlay() [D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Private\Actor.cpp:3849]
UnrealEditor_Engine!AWorldSettings::NotifyBeginPlay() [D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Private\WorldSettings.cpp:283]
UnrealEditor_Engine!AGameStateBase::HandleBeginPlay() [D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Private\GameStateBase.cpp:205]
UnrealEditor_Engine!UWorld::BeginPlay() [D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Private\World.cpp:4908]
UnrealEditor_Engine!UGameInstance::StartPlayInEditorGameInstance() [D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Private\GameInstance.cpp:500]
UnrealEditor_UnrealEd!UEditorEngine::CreateInnerProcessPIEGameInstance() [D:\build++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\PlayLevel.cpp:3052]
UnrealEditor_UnrealEd!UEditorEngine::OnLoginPIEComplete_Deferred() [D:\build++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\PlayLevel.cpp:1568]
UnrealEditor_UnrealEd!UEditorEngine::CreateNewPlayInEditorInstance() [D:\build++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\PlayLevel.cpp:1830]
UnrealEditor_UnrealEd!UEditorEngine::StartPlayInEditorSession() [D:\build++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\PlayLevel.cpp:2798]
UnrealEditor_DisplayClusterEditor!UDisplayClusterEditorEngine::StartPlayInEditorSession() [D:\build++UE5\Sync\Engine\Plugins\Runtime\nDisplay\Source\DisplayClusterEditor\Private\DisplayClusterEditorEngine.cpp:139]
UnrealEditor_UnrealEd!UEditorEngine::StartQueuedPlaySessionRequestImpl() [D:\build++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\PlayLevel.cpp:1148]
UnrealEditor_UnrealEd!UEditorEngine::StartQueuedPlaySessionRequest() [D:\build++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\PlayLevel.cpp:1051]
UnrealEditor_UnrealEd!UEditorEngine::Tick() [D:\build++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\EditorEngine.cpp:1665]
UnrealEditor_UnrealEd!UUnrealEdEngine::Tick() [D:\build++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\UnrealEdEngine.cpp:474]
UnrealEditor_DisplayClusterEditor!UDisplayClusterEditorEngine::Tick() [D:\build++UE5\Sync\Engine\Plugins\Runtime\nDisplay\Source\DisplayClusterEditor\Private\DisplayClusterEditorEngine.cpp:191]
UnrealEditor!FEngineLoop::Tick() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:5215]
UnrealEditor!GuardedMain() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\Launch.cpp:183]
UnrealEditor!GuardedMainWrapper() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:147]
UnrealEditor!LaunchWindowsStartup() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:283]
UnrealEditor!WinMain() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:330]
UnrealEditor!__scrt_common_main_seh() [d:\a01_work\6\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]

…about mid project Cesium began to become chunky, tiles popping-in quite noticeable.

i appreciate the help on this.

Yeah the call stack is much more helpful now that you have debug symbols. Can you tell me exactly which version of Cesium for Unreal you’re using, though, so I can match up the line numbers? You can find the version under Edit → Plugins.

Unreal 5.0.3. Cesium 1.15.1

I just noticed an option to update the Cesium plugin this morning.

Yes we release a new version at the beginning of each month. Sometimes more often if there’s an important bug fix. I don’t expect the upgrade to fix the problem you’re having, but it’s certainly worth a try.

But with your call stack and v1.15.1, the crash is happening on this line:

Honestly, that doesn’t make a lot of sense. It’s just using Unreal Engine’s built-in Actor iteration mechanism to loop through the Sequences in your level. I’d be looking for some kind of memory corruption - not necessarily related to the Cesium plugin at all - that is making basic operations like this unreliable.

Can you reproduce this problem in a minimal level that you can share with us? That’s probably the only way we’ll be able to debug it.