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When you reimport a Static Mesh with an Added Material ID associated with it and in the Static Mesh Editor assign a material, the engine crashes.
Also reproduced in Main Promotable-CL-2552010 & Releases/4.8/Promoted-CL-2550455
RESULTS: CRASH
EXPECTED: Material assigned with no crash
Assertion failed: StaticMesh.Materials.IsValidIndex(SlotIndex) [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.8\Engine\Source\Editor\StaticMeshEditor\Private\StaticMeshEditorTools.cpp] [Line: 1258] UE4Editor_StaticMeshEditor! FMeshSectionSettingsLayout::OnMaterialChanged() staticmesheditortools.cpp:1259 UE4Editor_StaticMeshEditor! TBaseSPMethodDelegateInstance<0,FMeshSectionSettingsLayout,0,TTypeWrapper<void> __cdecl() delegateinstancesimpl_variadics.inl:282 UE4Editor_StaticMeshEditor! TBaseSPMethodDelegateInstance<0,FMeshSectionSettingsLayout,0,void __cdecl() delegateinstancesimpl_variadics.inl:388 UE4Editor_PropertyEditor! FMaterialItemView::ReplaceMaterial() propertycustomizationhelpers.cpp:763 UE4Editor_PropertyEditor! TBaseSPMethodDelegateInstance<0,FMaterialItemView,0,TTypeWrapper<void> __cdecl() delegateinstancesimpl_variadics.inl:282 UE4Editor_PropertyEditor! TBaseSPMethodDelegateInstance<0,FMaterialItemView,0,void __cdecl() delegateinstancesimpl_variadics.inl:388 UE4Editor_PropertyEditor! SPropertyEditorAsset::SetValue() spropertyeditorasset.cpp:525 UE4Editor_PropertyEditor! TBaseSPMethodDelegateInstance<0,SPropertyEditorAsset,0,TTypeWrapper<void> __cdecl() delegateinstancesimpl_variadics.inl:282 UE4Editor_PropertyEditor! TBaseSPMethodDelegateInstance<0,SPropertyEditorAsset,0,void __cdecl() delegateinstancesimpl_variadics.inl:388 UE4Editor_PropertyEditor! SPropertyMenuAssetPicker::OnAssetSelected() spropertymenuassetpicker.cpp:232 UE4Editor_PropertyEditor! TBaseSPMethodDelegateInstance<0,SPropertyMenuAssetPicker,0,TTypeWrapper<void> __cdecl() delegateinstancesimpl_variadics.inl:282 UE4Editor_PropertyEditor! TBaseSPMethodDelegateInstance<0,SPropertyMenuAssetPicker,0,void __cdecl() delegateinstancesimpl_variadics.inl:388 UE4Editor_ContentBrowser! SAssetView::AssetSelectionChanged() sassetview.cpp:3076 UE4Editor_ContentBrowser! TBaseSPMethodDelegateInstance<0,SAssetView,0,TTypeWrapper<void> __cdecl() delegateinstancesimpl_variadics.inl:282 UE4Editor_ContentBrowser! TBaseSPMethodDelegateInstance<0,SAssetView,0,void __cdecl() delegateinstancesimpl_variadics.inl:388 UE4Editor_ContentBrowser! TBaseDelegate<void,TSharedPtr<FAssetViewItem,0>,enum ESelectInfo::Type>::ExecuteIfBound() delegatesignatureimpl_variadics.inl:519 UE4Editor_ContentBrowser! SListView<TSharedPtr<FAssetViewItem,0> >::Private_SignalSelectionChanged() slistview.h:609 UE4Editor_ContentBrowser! STableRow<TSharedPtr<FAssetViewItem,0> >::OnMouseButtonUp() stablerow.h:437 UE4Editor_Slate! <lambda_de96dc3471181973108233c6db1f9843>::operator() slateapplication.cpp:4169 UE4Editor_Slate! FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,<lambda_de96dc3471181973108233c6db1f9843> >() slateapplication.cpp:212 UE4Editor_Slate! FSlateApplication::ProcessMouseButtonUpEvent() slateapplication.cpp:4172 UE4Editor_Slate! FSlateApplication::OnMouseUp() slateapplication.cpp:4132 UE4Editor_Core! FWindowsApplication::ProcessDeferredMessage() windowsapplication.cpp:1406 UE4Editor_Core! FWindowsApplication::DeferMessage() windowsapplication.cpp:1711 UE4Editor_Core! FWindowsApplication::ProcessMessage() windowsapplication.cpp:706 UE4Editor_Core! FWindowsApplication::AppWndProc() windowsapplication.cpp:628 user32! <Unknown> user32! <Unknown> UE4Editor_Core! FWindowsPlatformMisc::PumpMessages() windowsplatformmisc.cpp:792 UE4Editor! FEngineLoop::Tick() launchengineloop.cpp:2319 UE4Editor! GuardedMain() launch.cpp:142 UE4Editor! GuardedMainWrapper() launchwindows.cpp:126 UE4Editor! WinMain() launchwindows.cpp:295
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