Unreal Engine crashes when deleting a foliage actor using the erase tool

Development World Creation
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1

When I create a foliage actor (Basic Trees) I have the ability to place the actors throughout the level but when I shift click to delete one or more of the trees Unreal engine crashes with the following error: Assertion failed: RemoveCount == 1 [File:D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Public\Instances\InstancedPlacementHash.h] [Line: 98]

The rest of the error proceeds as follows:

UnrealEditor_Foliage!FFoliageInfo::RemoveInstances() [D:\build++UE5\Sync\Engine\Source\Runtime\Foliage\Private\InstancedFoliage.cpp:2402]
UnrealEditor_Foliage!AInstancedFoliageActor::DeleteFoliageActorInstance() [D:\build++UE5\Sync\Engine\Source\Runtime\Foliage\Private\InstancedFoliage.cpp:5030]
UnrealEditor_FoliageEdit!UFoliageEditorSubsystem::OnActorDeleted() [D:\build++UE5\Sync\Engine\Source\Editor\FoliageEdit\Private\FoliageEditorSubsystem.cpp:169]
UnrealEditor_FoliageEdit!TBaseUObjectMethodDelegateInstance<0,UFoliageEditorSubsystem,void __cdecl(AActor *),FDefaultDelegateUserPolicy>::ExecuteIfSafe() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:667]
UnrealEditor_Engine!TMulticastDelegate<void __cdecl(AActor *),FDefaultDelegateUserPolicy>::Broadcast() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateSignatureImpl.inl:956]
UnrealEditor_Engine!UWorld::DestroyActor() [D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Private\LevelActor.cpp:997]
UnrealEditor_Foliage!FFoliageActor::RemoveInstance() [D:\build++UE5\Sync\Engine\Source\Runtime\Foliage\Private\FoliageActor.cpp:155]
UnrealEditor_Foliage!FFoliageInfo::RemoveInstancesImpl() [D:\build++UE5\Sync\Engine\Source\Runtime\Foliage\Private\InstancedFoliage.cpp:2442]
UnrealEditor_Foliage!FFoliageInfo::RemoveInstances() [D:\build++UE5\Sync\Engine\Source\Runtime\Foliage\Private\InstancedFoliage.cpp:2402]
UnrealEditor_FoliageEdit!FEdModeFoliage::RemoveInstancesForBrush'::2’::<lambda_1>::operator()() [D:\build++UE5\Sync\Engine\Source\Editor\FoliageEdit\Private\FoliageEdMode.cpp:1673]
UnrealEditor_FoliageEdit!UE::Core::Private::Function::TFunctionRefCaller<FEdModeFoliage::ForEachFoliageInfo'::2’::<lambda_1>,bool __cdecl(APartitionActor *)>::Call() [D:\build++UE5\Sync\Engine\Source\Runtime\Core\Public\Templates\Function.h:471]
UnrealEditor_Engine!FActorPartitionLevel::ForEachRelevantActor() [D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Private\ActorPartition\ActorPartitionSubsystem.cpp:145]
UnrealEditor_Engine!UActorPartitionSubsystem::ForEachRelevantActor() [D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Private\ActorPartition\ActorPartitionSubsystem.cpp:348]
UnrealEditor_FoliageEdit!FEdModeFoliage::ForEachFoliageInfo() [D:\build++UE5\Sync\Engine\Source\Editor\FoliageEdit\Private\FoliageEdMode.cpp:707]
UnrealEditor_FoliageEdit!FEdModeFoliage::RemoveInstancesForBrush() [D:\build++UE5\Sync\Engine\Source\Editor\FoliageEdit\Private\FoliageEdMode.cpp:1677]
UnrealEditor_FoliageEdit!FEdModeFoliage::ApplyBrush() [D:\build++UE5\Sync\Engine\Source\Editor\FoliageEdit\Private\FoliageEdMode.cpp:2665]
UnrealEditor_FoliageEdit!FEdModeFoliage::InputKey() [D:\build++UE5\Sync\Engine\Source\Editor\FoliageEdit\Private\FoliageEdMode.cpp:3648]
UnrealEditor_UnrealEd!ULegacyEdModeWrapper::InputKey() [D:\build++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\Tools\LegacyEdMode.cpp:194]
UnrealEditor_UnrealEd!FEditorModeTools::InputKey'::2’::<lambda_1>::operator()() [D:\build++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\EditorModeManager.cpp:1326]
UnrealEditor_UnrealEd!FEditorModeTools::ForEachEdMode() [D:\build++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\EditorModeManager.cpp:621]
UnrealEditor_UnrealEd!FEditorModeTools::InputKey() [D:\build++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\EditorModeManager.cpp:1321]
UnrealEditor_UnrealEd!FEditorViewportClient::Internal_InputKey() [D:\build++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\EditorViewportClient.cpp:2948]
UnrealEditor_UnrealEd!FLevelEditorViewportClient::InputKey() [D:\build++UE5\Sync\Engine\Source\Editor\UnrealEd\Private\LevelEditorViewport.cpp:3082]
UnrealEditor_Engine!FSceneViewport::OnMouseButtonDown() [D:\build++UE5\Sync\Engine\Source\Runtime\Engine\Private\Slate\SceneViewport.cpp:542]
UnrealEditor_Slate!SViewport::OnMouseButtonDown() [D:\build++UE5\Sync\Engine\Source\Runtime\Slate\Private\Widgets\SViewport.cpp:242]
UnrealEditor_Slate!FEventRouter::Route<FReply,FEventRouter::FBubblePolicy,FPointerEvent,FSlateApplication::RoutePointerDownEvent'::5’::<lambda_2> >() [D:\build++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:442]
UnrealEditor_Slate!FSlateApplication::RoutePointerDownEvent() [D:\build++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:5090]
UnrealEditor_Slate!FSlateApplication::ProcessMouseButtonDownEvent() [D:\build++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:5038]
UnrealEditor_Slate!FSlateApplication::OnMouseDown() [D:\build++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:4936]
UnrealEditor_ApplicationCore!FWindowsApplication::ProcessDeferredMessage() [D:\build++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:2239]
UnrealEditor_ApplicationCore!FWindowsApplication::DeferMessage() [D:\build++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:2738]
UnrealEditor_ApplicationCore!FWindowsApplication::ProcessMessage() [D:\build++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:1099]
UnrealEditor_ApplicationCore!FWindowsApplication::AppWndProc() [D:\build++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:937]
user32
user32
UnrealEditor_ApplicationCore!FWindowsPlatformApplicationMisc::PumpMessages() [D:\build++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsPlatformApplicationMisc.cpp:148]
UnrealEditor!FEngineLoop::Tick() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:5749]
UnrealEditor!GuardedMain() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\Launch.cpp:188]
UnrealEditor!GuardedMainWrapper() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:118]
UnrealEditor!LaunchWindowsStartup() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:258]
UnrealEditor!WinMain() [D:\build++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:298]
UnrealEditor!__scrt_common_main_seh() [D:\a_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
kernel32
ntdll

If anyone could give me any insight into what is going on I would very much appreciate it. As a new developer I could just be overlooking something very simple. Thanks in advance for any answers!

2

Hey there @scrodosagin! Welcome to the community! What version of the engine is this? Does this error occur with any foliage actors painted on by the foliage tool?

3

I have the same problem. 5.3.2.

4

Same problem

5

Hey there @SupportiveEntity, to answer your questions I am using Unreal Engine Version 5.3.2 and yes it happens with any and all foliage actors painted on by the foliage tool.

6

Interesting @scrodosagin! Does this error apply for other versions/installations as well? The error is basically failing an assertion that one object is being removed. Though it’s unclear how that would occur. If possible, also change the foliage brush to singular, and on a new map place just a cube that’s been converted to a foliage mesh. Can you erase that one or does the same error occur?

7

I’m using version 5.3.2 and I had this same issue and it was super annoying. I don’t know why it’s happening but I found a work around. When in the foliage mode, select the actors you wish to delete then right click and chose “Replace Selected Actors With”. You can then replace them with any random static mesh and then safely delete. This was bugging me for ages but this seems to work to get around this bug.

1 Like
8

I have the same problem. 5.3.2. And I change the foliage brush to singular, the same error occur.

foliage_crash_stack
foliage_crash_stack1920×1080 111 KB

Another problem is that when I switch levels and go back to the current level, I don’t see any foliage.

9

same problem, ue crash when deleting foliage

appError called: Assertion failed: RemoveCount == 1 [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Engine\Public\Instances\InstancedPlacementHash.h] [Line: 98]