你好 stackoverflow 社区，
第一次问。
我正在开发一个原型，用于使用虚幻引擎在 VR 中对 CAD 数据进行建模。我已经设法让我的 Unreal 项目使用我的 CAD 系统 Siemens NX 构建，或者更确切地说是 API NXOpen。
总的来说，API 可以工作，我可以调用 NXOpen 函数并可以创建基本对象但是某些操作会导致崩溃，我的猜测是它与内存管理有关。我无法理解到底发生了什么。
例如，我有代码可以创建一个运行良好的 NX 块功能。之后，我需要一个存储在块特征内的 body 对象。访问也有效，但是当“body”超出范围时，它会崩溃。访问 NX 功能中的各种数据时也会发生类似的崩溃。这个虚拟代码经常触发崩溃：
// 'block' gets created here
if (block) {
std::vector<NXOpen::Body*> bodies = block->GetBodies();
if (bodies.size() > 0) {
NXOpen::Body* body = bodies.front();
}
} // <-- this line crashes
Exception thrown: read access violation.
**flag** was 0xFFFFFFFFFFFFFFFF. occurred
[Inline Frame] UE4Editor-Core.dll!__TBB_machine_cmpswp1(volatile void *) Line 69 C++
> [Inline Frame] UE4Editor-Core.dll!__TBB_TryLockByte(unsigned char &) Line 917 C++
UE4Editor-Core.dll!__TBB_LockByte(unsigned char & flag) Line 924 C++
[Inline Frame] UE4Editor-Core.dll!MallocMutex::scoped_lock::{ctor}(MallocMutex &) Line 66 C++
UE4Editor-Core.dll!rml::internal::Block::freePublicObject(rml::internal::FreeObject * objectToFree) Line 1382 C++
[Inline Frame] UE4Editor-Core.dll!rml::internal::internalPoolFree(rml::internal::MemoryPool * memPool, void *) Line 2571 C++
UE4Editor-Core.dll!rml::internal::internalFree(void * object) Line 2595 C++
UE4Editor-Core.dll!FMemory::Free(void * Original) Line 76 C++
UE4Editor-GestEnUE-Win64-DebugGame.dll!operator delete(void * Ptr, unsigned __int64 Size) Line 6 C++
[External Code]
UE4Editor-GestEnUE-Win64-DebugGame.dll!UNXConnection::AddPointSetsToBody(const FString & name) Line 268 C++
UE4Editor-GestEnUE-Win64-DebugGame.dll!ANXPart::AddCylinder(FVector pos, FVector axis, float height, float diameter, bool WorldSpace) Line 103 C++
UE4Editor-GestEnUE-Win64-DebugGame.dll!ANXPart::execAddCylinder(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 18 C++
UE4Editor-CoreUObject.dll!UFunction::Invoke(UObject * Obj, FFrame & Stack, void * const Z_Param__Result) Line 4643 C++
UE4Editor-CoreUObject.dll!UObject::CallFunction(FFrame & Stack, void * const Z_Param__Result, UFunction * Function) Line 904 C++
[Inline Frame] UE4Editor-CoreUObject.dll!FFrame::Step(UObject *) Line 319 C++
UE4Editor-CoreUObject.dll!UObject::ProcessContextOpcode(FFrame & Stack, void * const Z_Param__Result, bool bCanFailSilently) Line 2314 C++
[Inline Frame] UE4Editor-CoreUObject.dll!FFrame::Step(UObject *) Line 319 C++
UE4Editor-CoreUObject.dll!UObject::execLetObj(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 2136 C++
[Inline Frame] UE4Editor-CoreUObject.dll!FFrame::Step(UObject *) Line 319 C++
UE4Editor-CoreUObject.dll!ProcessLocalScriptFunction(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 974 C++
UE4Editor-CoreUObject.dll!ProcessScriptFunction<void (__cdecl*)(UObject *,FFrame &,void *)>(UObject * Context, UFunction * Function, FFrame & Stack, void * const Z_Param__Result, void(*)(UObject *, FFrame &, void *) ExecFtor) Line 809 C++
UE4Editor-CoreUObject.dll!ProcessLocalFunction(UObject * Context, UFunction * Fn, FFrame & Stack, void * const Z_Param__Result) Line 1033 C++
[Inline Frame] UE4Editor-CoreUObject.dll!FFrame::Step(UObject *) Line 319 C++
UE4Editor-CoreUObject.dll!ProcessLocalScriptFunction(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 974 C++
UE4Editor-CoreUObject.dll!ProcessScriptFunction<void (__cdecl*)(UObject *,FFrame &,void *)>(UObject * Context, UFunction * Function, FFrame & Stack, void * const Z_Param__Result, void(*)(UObject *, FFrame &, void *) ExecFtor) Line 809 C++
UE4Editor-CoreUObject.dll!ProcessLocalFunction(UObject * Context, UFunction * Fn, FFrame & Stack, void * const Z_Param__Result) Line 1033 C++
[Inline Frame] UE4Editor-CoreUObject.dll!FFrame::Step(UObject *) Line 319 C++
UE4Editor-CoreUObject.dll!UObject::ProcessContextOpcode(FFrame & Stack, void * const Z_Param__Result, bool bCanFailSilently) Line 2314 C++
[Inline Frame] UE4Editor-CoreUObject.dll!FFrame::Step(UObject *) Line 319 C++
UE4Editor-CoreUObject.dll!ProcessLocalScriptFunction(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 974 C++
UE4Editor-CoreUObject.dll!ProcessScriptFunction<void (__cdecl*)(UObject *,FFrame &,void *)>(UObject * Context, UFunction * Function, FFrame & Stack, void * const Z_Param__Result, void(*)(UObject *, FFrame &, void *) ExecFtor) Line 809 C++
UE4Editor-CoreUObject.dll!ProcessLocalFunction(UObject * Context, UFunction * Fn, FFrame & Stack, void * const Z_Param__Result) Line 1033 C++
[Inline Frame] UE4Editor-CoreUObject.dll!FFrame::Step(UObject *) Line 319 C++
UE4Editor-CoreUObject.dll!ProcessLocalScriptFunction(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 974 C++
UE4Editor-CoreUObject.dll!UObject::ProcessInternal(UObject * Context, FFrame & Stack, void * const Z_Param__Result) Line 1058 C++
UE4Editor-CoreUObject.dll!UFunction::Invoke(UObject * Obj, FFrame & Stack, void * const Z_Param__Result) Line 4643 C++
UE4Editor-CoreUObject.dll!UObject::ProcessEvent(UFunction * Function, void * Parms) Line 1464 C++
UE4Editor-Engine.dll!AActor::ProcessEvent(UFunction * Function, void * Parameters) Line 769 C++
UE4Editor-GestEnUE-Win64-DebugGame.dll!ABuilderBase::commit() Line 37 C++
UE4Editor-GestEnUE-Win64-DebugGame.dll!AGestEnLeapPawn::Tick(float DeltaTime) Line 138 C++
UE4Editor-Engine.dll!AActor::TickActor(float DeltaSeconds, ELevelTick TickType, FActorTickFunction & ThisTickFunction) Line 970 C++
UE4Editor-Engine.dll!FActorTickFunction::ExecuteTick(float DeltaTime, ELevelTick TickType, ENamedThreads::Type CurrentThread, const TRefCountPtr<FGraphEvent> & MyCompletionGraphEvent) Line 164 C++
[Inline Frame] UE4Editor-Engine.dll!FTickFunctionTask::DoTask(ENamedThreads::Type) Line 285 C++
UE4Editor-Engine.dll!TGraphTask<FTickFunctionTask>::ExecuteTask(TArray<FBaseGraphTask *,FDefaultAllocator> & NewTasks, ENamedThreads::Type CurrentThread) Line 842 C++
[Inline Frame] UE4Editor-Core.dll!FBaseGraphTask::Execute(TArray<FBaseGraphTask *,FDefaultAllocator> & CurrentThread, ENamedThreads::Type) Line 511 C++
UE4Editor-Core.dll!FNamedTaskThread::ProcessTasksNamedThread(int QueueIndex, bool bAllowStall) Line 686 C++
UE4Editor-Core.dll!FNamedTaskThread::ProcessTasksUntilQuit(int QueueIndex) Line 582 C++
[Inline Frame] UE4Editor-Core.dll!FTaskGraphImplementation::ProcessThreadUntilRequestReturn(ENamedThreads::Type) Line 1406 C++
UE4Editor-Core.dll!FTaskGraphImplementation::WaitUntilTasksComplete(const TArray<TRefCountPtr<FGraphEvent>,TInlineAllocator<4,FDefaultAllocator> > & Tasks, ENamedThreads::Type CurrentThreadIfKnown) Line 1457 C++
UE4Editor-Engine.dll!FTickTaskSequencer::ReleaseTickGroup(ETickingGroup WorldTickGroup, bool bBlockTillComplete) Line 557 C++
UE4Editor-Engine.dll!FTickTaskManager::RunTickGroup(ETickingGroup Group, bool bBlockTillComplete) Line 1505 C++
UE4Editor-Engine.dll!UWorld::RunTickGroup(ETickingGroup Group, bool bBlockTillComplete) Line 789 C++
UE4Editor-Engine.dll!UWorld::Tick(ELevelTick TickType, float DeltaSeconds) Line 1568 C++
UE4Editor-UnrealEd.dll!UEditorEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 1618 C++
UE4Editor-UnrealEd.dll!UUnrealEdEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 403 C++
UE4Editor-Win64-DebugGame.exe!FEngineLoop::Tick() Line 3967 C++
[Inline Frame] UE4Editor-Win64-DebugGame.exe!EngineTick() Line 62 C++
UE4Editor-Win64-DebugGame.exe!GuardedMain(const wchar_t * CmdLine, HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, int nCmdShow) Line 168 C++
UE4Editor-Win64-DebugGame.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow) Line 261 C++
如果我正确理解了调用堆栈，则会在删除对象时发生错误。但为什么这会是问题所在？会不会是 Unreal 和 NX 第三方库都试图管理内存？
有没有人知道什么可能导致这些崩溃，甚至知道如何解决它？如有必要，我很乐意提供更多信息。
问候，拉拉纳里卡