Unreal Engine Issues and Bug Tracker (UE-149468)

Description

Cascade to Niagara conversion causes the editor to crash due to any distribution parameter in the Particle Emitter being reset to none.

Repro Rate: 4/4

Tested this in //UE4/Release-4.27 @ CL# 18319896 and the issue occurred there, it is not a regression.

Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000000000000010

Steps to Reproduce

Create a new Blank BP project
Enable Cascade To Niagara Converter plugin and restart the editor. (Edit > Plugins)
Right-Click in the Content Browser, create a Cascade Particle System (Legacy). (Under Miscellaneous)
Open the Cascade Particle System
Select Spawn under the Particle Emitter
In Details, find Rate Scale > Distribution; Click on the revert arrow to default.
Close the particle editor
Right-Click on the Cascade Particle System and Convert to Niagara System

Results: Crash occurs due to invalid distribution settings in the Cascade Particle System during conversion.
Expected: Particle System converts successfully and defaults invalid distributions to Niagara defaults if an invalid value is received.

Callstack

Error: === Critical error: ===
Error: 
Error: Fatal error!
Error: 
Error: Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000000000000010
Error: 
Error: [Callstack] 0x00007ffb8115c4ae UnrealEditor-CascadeToNiagaraConverter.dll!UFXConverterUtilitiesLibrary::GetDistributionMinMaxValues() [D:\build\++UE5\Sync\Engine\Plugins\FX\CascadeToNiagaraConverter\Source\CascadeToNiagaraConverter\Private\NiagaraStackGraphUtilitiesAdapterLibrary.cpp:1210]
Error: [Callstack] 0x00007ffb81171ba7 UnrealEditor-CascadeToNiagaraConverter.dll!UFXConverterUtilitiesLibrary::execGetDistributionMinMaxValues() [D:\build\++UE5\Sync\Engine\Plugins\FX\CascadeToNiagaraConverter\Intermediate\Build\Win64\UnrealEditor\Inc\CascadeToNiagaraConverter\NiagaraStackGraphUtilitiesAdapterLibrary.gen.cpp:3723]
Error: [Callstack] 0x00007ffbc120bcb7 UnrealEditor-CoreUObject.dll!UFunction::Invoke() [D:\build\++UE5\Sync\Engine\Source\Runtime\CoreUObject\Private\UObject\Class.cpp:5912]
Error: [Callstack] 0x00007ffbc14317a7 UnrealEditor-CoreUObject.dll!UObject::ProcessEvent() [D:\build\++UE5\Sync\Engine\Source\Runtime\CoreUObject\Private\UObject\ScriptCore.cpp:2003]
Error: [Callstack] 0x00007ffb826d6cf1 UnrealEditor-PythonScriptPlugin.dll!PyUtil::InvokeFunctionCall() [D:\build\++UE5\Sync\Engine\Plugins\Experimental\PythonScriptPlugin\Source\PythonScriptPlugin\Private\PyUtil.cpp:557]
Error: [Callstack] 0x00007ffb826b8601 UnrealEditor-PythonScriptPlugin.dll!FPyWrapperObject::CallFunction_Impl() [D:\build\++UE5\Sync\Engine\Plugins\Experimental\PythonScriptPlugin\Source\PythonScriptPlugin\Private\PyWrapperObject.cpp:301]
Error: [Callstack] 0x00007ffb826b6c53 UnrealEditor-PythonScriptPlugin.dll!FPyWrapperObject::CallClassMethodWithArgs_Impl() [D:\build\++UE5\Sync\Engine\Plugins\Experimental\PythonScriptPlugin\Source\PythonScriptPlugin\Private\PyWrapperObject.cpp:320]
Error: [Callstack] 0x00007ffb8266c95e UnrealEditor-PythonScriptPlugin.dll!FPyMethodWithClosureDef::Call() [D:\build\++UE5\Sync\Engine\Plugins\Experimental\PythonScriptPlugin\Source\PythonScriptPlugin\Private\PyMethodWithClosure.cpp:152]
Error: [Callstack] 0x00007ffb9b791a63 python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b78aaa3 python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b78c487 python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b78f2aa python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b785af7 python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b78f2aa python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b785af7 python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b78f2aa python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b78f9ea python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b78f9ea python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b78c3a4 python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b78f2aa python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b78aaa3 python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b7a4735 python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b7a606f python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb9b7a60b1 python39.dll!UnknownFunction []
Error: [Callstack] 0x00007ffb82670a76 UnrealEditor-PythonScriptPlugin.dll!FPythonScriptPlugin::EvalString() [D:\build\++UE5\Sync\Engine\Plugins\Experimental\PythonScriptPlugin\Source\PythonScriptPlugin\Private\PythonScriptPlugin.cpp:1277]
Error: [Callstack] 0x00007ffb8269f919 UnrealEditor-PythonScriptPlugin.dll!FPythonScriptPlugin::RunFile() [D:\build\++UE5\Sync\Engine\Plugins\Experimental\PythonScriptPlugin\Source\PythonScriptPlugin\Private\PythonScriptPlugin.cpp:1397]
Error: [Callstack] 0x00007ffb82670e87 UnrealEditor-PythonScriptPlugin.dll!FPythonScriptPlugin::ExecPythonCommandEx() [D:\build\++UE5\Sync\Engine\Plugins\Experimental\PythonScriptPlugin\Source\PythonScriptPlugin\Private\PythonScriptPlugin.cpp:573]
Error: [Callstack] 0x00007ffb8115b182 UnrealEditor-CascadeToNiagaraConverter.dll!ICascadeToNiagaraConverterModule::ExecuteConvertCascadeSystemToNiagaraSystem() [D:\build\++UE5\Sync\Engine\Plugins\FX\CascadeToNiagaraConverter\Source\CascadeToNiagaraConverter\Private\CascadeToNiagaraConverterModule.cpp:90]
Error: [Callstack] 0x00007ffb81154013 UnrealEditor-CascadeToNiagaraConverter.dll!UE::Core::Private::Tuple::TTupleBase<TIntegerSequence<unsigned int,0>,TArray<UParticleSystem *,TSizedDefaultAllocator<32> > >::ApplyAfter<void (__cdecl*const &)(TArray<UParticleSystem *,TSizedDefaultAllocator<32> >)>() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Templates\Tuple.h:324]
Error: [Callstack] 0x00007ffb8115b3f1 UnrealEditor-CascadeToNiagaraConverter.dll!TBaseStaticDelegateInstance<void __cdecl(void),FDefaultDelegateUserPolicy,TArray<UParticleSystem *,TSizedDefaultAllocator<32> > >::ExecuteIfSafe() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:731]
Error: [Callstack] 0x00007ffbc086d46d UnrealEditor-Slate.dll!SMenuEntryBlock::OnClicked() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\MultiBox\SMenuEntryBlock.cpp:1157]
Error: [Callstack] 0x00007ffbc086e3f0 UnrealEditor-Slate.dll!SMenuEntryBlock::OnMenuItemButtonClicked() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\MultiBox\SMenuEntryBlock.cpp:1108]
Error: [Callstack] 0x00007ffbc0850814 UnrealEditor-Slate.dll!TBaseSPMethodDelegateInstance<0,SMenuEntryBlock,1,FReply __cdecl(void),FDefaultDelegateUserPolicy>::Execute() [D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:290]
Error: [Callstack] 0x00007ffbc08eb90b UnrealEditor-Slate.dll!SButton::ExecuteOnClick() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Widgets\Input\SButton.cpp:464]
Error: [Callstack] 0x00007ffbc0912cc6 UnrealEditor-Slate.dll!SButton::OnMouseButtonUp() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Widgets\Input\SButton.cpp:389]
Error: [Callstack] 0x00007ffbc086e4dc UnrealEditor-Slate.dll!SMenuEntryButton::OnMouseButtonUp() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\MultiBox\SMenuEntryBlock.cpp:434]
Error: [Callstack] 0x00007ffbc06b4034 UnrealEditor-Slate.dll!<lambda_51e270ca99ea7ce852539efd04dd453f>::operator()() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:4961]
Error: [Callstack] 0x00007ffbc0696fc6 UnrealEditor-Slate.dll!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,<lambda_51e270ca99ea7ce852539efd04dd453f> >() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:405]
Error: [Callstack] 0x00007ffbc07102de UnrealEditor-Slate.dll!FSlateApplication::RoutePointerUpEvent() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:4947]
Error: [Callstack] 0x00007ffbc06f91b1 UnrealEditor-Slate.dll!FSlateApplication::ProcessMouseButtonUpEvent() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:5495]
Error: [Callstack] 0x00007ffbc06ed5dc UnrealEditor-Slate.dll!FSlateApplication::OnMouseUp() [D:\build\++UE5\Sync\Engine\Source\Runtime\Slate\Private\Framework\Application\SlateApplication.cpp:5460]
Error: [Callstack] 0x00007ffbe926a92e UnrealEditor-ApplicationCore.dll!FWindowsApplication::ProcessDeferredMessage() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:2210]
Error: [Callstack] 0x00007ffbe9259247 UnrealEditor-ApplicationCore.dll!FWindowsApplication::DeferMessage() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:2699]
Error: [Callstack] 0x00007ffbe926ce51 UnrealEditor-ApplicationCore.dll!FWindowsApplication::ProcessMessage() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:1078]
Error: [Callstack] 0x00007ffbe92549a7 UnrealEditor-ApplicationCore.dll!FWindowsApplication::AppWndProc() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsApplication.cpp:916]
Error: [Callstack] 0x00007ffc545363ed USER32.dll!UnknownFunction []
Error: [Callstack] 0x00007ffc54535de2 USER32.dll!UnknownFunction []
Error: [Callstack] 0x00007ffbe926e148 UnrealEditor-ApplicationCore.dll!FWindowsPlatformApplicationMisc::PumpMessages() [D:\build\++UE5\Sync\Engine\Source\Runtime\ApplicationCore\Private\Windows\WindowsPlatformApplicationMisc.cpp:138]
Error: [Callstack] 0x00007ff756d17114 UnrealEditor.exe!FEngineLoop::Tick() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:5139]
Error: [Callstack] 0x00007ff756d30d9c UnrealEditor.exe!GuardedMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Launch.cpp:183]
Error: [Callstack] 0x00007ff756d30e8a UnrealEditor.exe!GuardedMainWrapper() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:147]
Error: [Callstack] 0x00007ff756d33c4d UnrealEditor.exe!LaunchWindowsStartup() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:283]
Error: [Callstack] 0x00007ff756d45534 UnrealEditor.exe!WinMain() [D:\build\++UE5\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:330]
Error: [Callstack] 0x00007ff756d486e6 UnrealEditor.exe!__scrt_common_main_seh() [d:\a01\_work\6\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
Error: [Callstack] 0x00007ffc536d7bd4 KERNEL32.DLL!UnknownFunction []
Error: [Callstack] 0x00007ffc5504ced1 ntdll.dll!UnknownFunction []

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Fixed

Component	UE - Niagara
Affects Versions	5.0
Target Fix	5.4

Fix Commit	31479782
Main Commit	31480063
Release Commit	31479851

Created	Apr 18, 2022
Resolved	Feb 14, 2024
Updated	Feb 21, 2024

UE-149468

Parameter distributions can be reset to None in Cascade Particle Systems, causing Cascade to Niagara conversion to crash the editor.

Parameter distributions can be reset to None in Cascade Particle Systems, causing Cascade to Niagara conversion to crash the editor.

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