# \[Crash\] BP LocalVar crash when try to Create External Curve

**URL:** <https://forums.unrealengine.com/t/crash-bp-localvar-crash-when-try-to-create-external-curve/369549>\
**Category:** C++\
**Tags:** unreal-engine, crash, bug-report, editor, question, Blueprint\
**Created:** [September 6, 2016, 10:46am UTC](https://forums.unrealengine.com/t/crash-bp-localvar-crash-when-try-to-create-external-curve/369549 "2016-09-06T10:46:19Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![dorgon\_chang](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/dorgon_chang/32/1124941_2.png) [@dorgon\_chang](https://forums.unrealengine.com/u/dorgon_chang)\
**Post date:** [September 6, 2016, 10:46am UTC](https://forums.unrealengine.com/t/crash-bp-localvar-crash-when-try-to-create-external-curve/369549/1 "2016-09-06T10:46:19Z")

</div>

step to reproduce:

1.create my own USTRUCT:

```
USTRUCT()
struct MYPROJECT_API FMyCustomCurve
{
	GENERATED_BODY()
public:
    ....
	UPROPERTY(config, EditAnywhere, meta = (
		DisplayName = "Custom Tween Curve",
		XAxisName = "Alpha", YAxisName = "Value"))
		FRuntimeFloatCurve CustomCurve;
};

```

2.add structure to a BP Function local variable.  
3.Press Create External Curve for structure.

4.Crash.

After trace code, I find out Owner is nullptr which in  
void FCurveStructCustomization::CustomizeHeader, OuterObjects is 0.  
…\Epic Games\4.13\Engine\Source\Editor\DetailCustomizations\Private\CurveStructCustomization.cpp : 64

here is C++ Call Stack:

```
UE4Editor-CoreUObject.dll!UObjectBaseUtility::GetName() Line 345	C++

```

> UE4Editor-DetailCustomizations.dll!FCurveStructCustomization::OnCreateButtonClicked() Line 268 C++  
> UE4Editor-DetailCustomizations.dll!TMemberFunctionCaller\<FCurveStructCustomization,FReply (\_\_cdecl FCurveStructCustomization::_)(void) \_\_ptr64\>::operator()\<\>() Line 161 C++  
> UE4Editor-DetailCustomizations.dll!TTupleImpl\<TIntegerSequence \>::ApplyAfter\<TMemberFunctionCaller\<FCurveStructCustomization,FReply (\_\_cdecl FCurveStructCustomization::_)(void) \_\_ptr64\> \>(TMemberFunctionCaller\<FCurveStructCustomization,FReply (\_\_cdecl FCurveStructCustomization::\*)(void)\> && Func) Line 115 C++  
> UE4Editor-DetailCustomizations.dll!TBaseSPMethodDelegateInstance\<0,FCurveStructCustomization,0,FReply \_\_cdecl(void)\>::Execute() Line 317 C++  
> UE4Editor-Slate.dll!TBaseDelegate::Execute() Line 521 C++  
> UE4Editor-Slate.dll!SButton::OnMouseButtonUp(const FGeometry & MyGeometry, const FPointerEvent & MouseEvent) Line 278 C++  
> UE4Editor-Slate.dll!FSlateApplication::RoutePointerUpEvent::\_\_l8::(const FArrangedWidget & TargetWidget, const FPointerEvent & Event) Line 4901 C++  
> UE4Editor-Slate.dll!FEventRouter::Route\<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,FReply (const FArrangedWidget &, const FPointerEvent &) \>(FSlateApplication \* ThisApplication, FEventRouter::FToLeafmostPolicy RoutingPolicy, FPointerEvent EventCopy, const FSlateApplication::RoutePointerUpEvent::**l8::FReply (const FArrangedWidget &, const FPointerEvent &) & Lambda) Line 215 C++  
> UE4Editor-Slate.dll!FSlateApplication::RoutePointerUpEvent(FWidgetPath & WidgetsUnderPointer, FPointerEvent & PointerEvent) Line 4890 C++  
> UE4Editor-Slate.dll!FSlateApplication::ProcessMouseButtonUpEvent(FPointerEvent & MouseEvent) Line 5348 C++  
> UE4Editor-Slate.dll!FSlateApplication::OnMouseUp(const EMouseButtons::Type Button, const FVector2D CursorPos) Line 5328 C++  
> UE4Editor-Core.dll!FWindowsApplication::ProcessDeferredMessage(const FDeferredWindowsMessage & DeferredMessage) Line 1584 C++  
> UE4Editor-Core.dll!FWindowsApplication::DeferMessage(TSharedPtr\<FWindowsWindow,0\> & NativeWindow, HWND **\* InHWnd, unsigned int InMessage, unsigned** int64 InWParam, int64 InLParam, int MouseX, int MouseY, unsigned int RawInputFlags) Line 1930 C++  
> UE4Editor-Core.dll!FWindowsApplication::ProcessMessage(HWND \* hwnd, unsigned int msg, unsigned int64 wParam, int64 lParam) Line 747 C++  
> UE4Editor-Core.dll!FWindowsApplication::AppWndProc(HWND \* hwnd, unsigned int msg, unsigned int64 wParam, int64 lParam) Line 669 C++  
> [External Code]   
> UE4Editor-Core.dll!FWindowsPlatformMisc::PumpMessages(bool bFromMainLoop) Line 905 C++  
> UE4Editor.exe!FEngineLoop::Tick() Line 2788 C++  
> UE4Editor.exe!GuardedMain(const wchar\_t \* CmdLine, HINSTANCE \* hInInstance, HINSTANCE \* hPrevInstance, int nCmdShow) Line 156 C++  
> UE4Editor.exe!WinMain(HINSTANCE \* hInInstance, HINSTANCE** \* hPrevInstance, char \* \_\_formal, int nCmdShow) Line 191 C++

---

<div class="post-metadata">

**Author:** ![anonymous\_user\_2b03d27c](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_2b03d27c](https://forums.unrealengine.com/u/anonymous_user_2b03d27c)\
**Post date:** [September 6, 2016, 7:29pm UTC](https://forums.unrealengine.com/t/crash-bp-localvar-crash-when-try-to-create-external-curve/369549/2 "2016-09-06T19:29:51Z")

</div>

Hey dorgon-

I was able to reproduce the crash and have entered a ticket for this that you can follow here ([Unreal Engine Issues and Bug Tracker (UE-35629)](https://issues.unrealengine.com/issue/UE-35629) ). As a workaround, you can create a global variable of the same struct and create the External Curve, then set the external curve for the local variable to the same asset that was created.

Cheers