Crash Importing Skeletal Mesh LODs with a lot of morph targets

Crash Importing Skeletal Mesh LODs with a lot of morph targets

Error message:

Source Context:

   49       }
   50       
   51       
   52       void UMorphTarget::CreateMorphMeshStreams( const FMorphMeshRawSource& BaseSource, const FMorphMeshRawSource& TargetSource, int32 LODIndex, bool bCompareNormal )
   53       {
   54       check(BaseSource.IsValidTarget(TargetSource));
   55       
   56       // create the LOD entry if it doesn't already exist
   57       if( LODIndex == MorphLODModels.Num() )
   58       {
   59       new(MorphLODModels) FMorphTargetLODModel();
   60       }
   61       
   62       // morph mesh data to modify
   63 ***** FMorphTargetLODModel& MorphModel = MorphLODModels[LODIndex];
   64       // copy the wedge point indices
   65       // for now just keep every thing 
   66       
   67       // set the original number of vertices
   68       MorphModel.NumBaseMeshVerts = BaseSource.Vertices.Num();
   69       
   70       // empty morph mesh vertices first
   71       MorphModel.Vertices.Empty();
   72       
   73       // array to mark processed base vertices
   74       TArray<bool> WasProcessed;
   75       WasProcessed.Empty(BaseSource.Vertices.Num());
   76       WasProcessed.AddZeroed(BaseSource.Vertices.Num());
   77       
   78       

Most recent user affected CL: 2946394

Logs:
[Link Removed]
[Link Removed]

CrashReporter User Descriptions:
-EUS [Name Removed] - Crash while importing Skeletal Mesh LOD (seems to occur while importing the morph targets)
-[Name Removed] here. I send the FBX files in question to [Name Removed] now

1. Download and unpack this file: [Link Removed]
2. Import LOD0
3. Open the Skeletal Mesh
4. Under LOD Settings, select Import LOD Level 1 under LOD Import
5. Choose the LOD1 fbx file
6. Repeat Step 4, but choose the LOD2, then LOD3, and so on

Result: During one of these imports, the editor will crash
Expected: Editor imports LODs successfully

UE4Editor_Engine!UMorphTarget::CreateMorphMeshStreams() morphtools.cpp:64
UE4Editor_Engine!UMorphTarget::PostProcess() morphtools.cpp:49
UE4Editor_UnrealEd!UnFbx::FFbxImporter::ImportMorphTargetsInternal() fbxskeletalmeshimport.cpp:2904
UE4Editor_UnrealEd!UnFbx::FFbxImporter::ImportFbxMorphTarget() fbxskeletalmeshimport.cpp:2931
UE4Editor_UnrealEd!FbxMeshUtils::ImportSkeletalMeshLOD() fbxmeshutils.cpp:306
UE4Editor_UnrealEd!FbxMeshUtils::ImportMeshLODDialog() fbxmeshutils.cpp:410
UE4Editor_Persona!FPersonaMeshDetails::OnImportLOD() personameshdetails.cpp:659
UE4Editor_Persona!TBaseSPMethodDelegateInstance<0,FPersonaMeshDetails,0,TTypeWrapper<void> __cdecl() delegateinstancesimpl_variadics.inl:321
UE4Editor_Persona!TBaseSPMethodDelegateInstance<0,FPersonaMeshDetails,0,void __cdecl() delegateinstancesimpl_variadics.inl:428
UE4Editor_Slate!TBaseDelegate<void,TSharedPtr<FString,0>,enum ESelectInfo::Type>::ExecuteIfBound() delegatesignatureimpl_variadics.inl:608
UE4Editor_Slate!STextComboBox::OnSelectionChanged() stextcombobox.cpp:71
UE4Editor_Slate!TBaseSPMethodDelegateInstance<0,STextComboBox,0,TTypeWrapper<void> __cdecl() delegateinstancesimpl_variadics.inl:321
UE4Editor_Slate!TBaseSPMethodDelegateInstance<0,STextComboBox,0,void __cdecl() delegateinstancesimpl_variadics.inl:428
UE4Editor_Slate!TBaseDelegate<void,TSharedPtr<FString,0>,enum ESelectInfo::Type>::ExecuteIfBound() delegatesignatureimpl_variadics.inl:608
UE4Editor_Slate!SComboBox<TSharedPtr<FString,0> >::OnSelectionChanged_Internal() scombobox.h:325
UE4Editor_Slate!TBaseSPMethodDelegateInstance<0,SComboBox<TSharedPtr<FString,0> >,0,TTypeWrapper<void> __cdecl() delegateinstancesimpl_variadics.inl:321
UE4Editor_Slate!TBaseSPMethodDelegateInstance<0,SComboBox<TSharedPtr<FString,0> >,0,void __cdecl() delegateinstancesimpl_variadics.inl:428
UE4Editor_Slate!TBaseDelegate<void,TSharedPtr<FString,0>,enum ESelectInfo::Type>::ExecuteIfBound() delegatesignatureimpl_variadics.inl:608
UE4Editor_Slate!SListView<TSharedPtr<FString,0> >::Private_SignalSelectionChanged() slistview.h:609
UE4Editor_Slate!STableRow<TSharedPtr<FString,0> >::OnMouseButtonUp() stablerow.h:449
UE4Editor_Slate!<lambda_9ed539f2a96fd1ccd6d2214174cc7705>::operator() slateapplication.cpp:4540
UE4Editor_Slate!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,<lambda_9ed539f2a96fd1ccd6d2214174cc7705> >() slateapplication.cpp:214
UE4Editor_Slate!FSlateApplication::RoutePointerUpEvent() slateapplication.cpp:4530
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonUpEvent() slateapplication.cpp:4947
UE4Editor_Slate!FSlateApplication::OnMouseUp() slateapplication.cpp:4923
UE4Editor_Core!FWindowsApplication::ProcessDeferredMessage() windowsapplication.cpp:1415
UE4Editor_Core!FWindowsApplication::DeferMessage() windowsapplication.cpp:1732
UE4Editor_Core!FWindowsApplication::ProcessMessage() windowsapplication.cpp:697
UE4Editor_Core!FWindowsApplication::AppWndProc() windowsapplication.cpp:619
user32!<Unknown>
user32!<Unknown>
UE4Editor_Core!FWindowsPlatformMisc::PumpMessages() windowsplatformmisc.cpp:884
UE4Editor!FEngineLoop::Tick() launchengineloop.cpp:2611
UE4Editor!GuardedMain() launch.cpp:142
UE4Editor!GuardedMainWrapper() launchwindows.cpp:126
UE4Editor!WinMain() launchwindows.cpp:200
UE4Editor!__scrt_common_main_seh() exe_common.inl:264
kernel32!<Unknown>
ntdll!<Unknown>

UE crashes when importing too many LODs with morphs