HISMC crash upon play

Development Programming & Scripting
1

i have setup-ed a simple c++ code with the Hierarchical instanced static mesh.

// in constructor 
static ConstructorHelpers::FObjectFinder<UStaticMesh> MountainMesh(TEXT("StaticMesh'/Game/Voronoi/Monkey.Monkey'"));
MountainSpawner = CreateDefaultSubobject<UHierarchicalInstancedStaticMeshComponent>(TEXT("MountainSpawner"));
MountainSpawner->RegisterComponent();
MountainSpawner->AttachTo(RootComponent);

MountainSpawner->SetStaticMesh(MountainMesh.Object);

for (int32 a = 0; a < 10; a++) {

	FRotator rotate = FRotator(0, FMath::RandRange(0, 360), 0);
	FVector Location = FVector(FMath::RandRange(0, SurfaceWidth*MapScale), FMath::RandRange(0, SurfaceHeight*MapScale), FMath::RandRange(-200, 0));
	int32 XYScale = FMath::RandRange(5, 12);
	FVector Scale = FVector(XYScale, XYScale, XYScale);
	MountainSpawner->AddInstance(FTransform(rotate, Location, Scale));
}

the last entry before the error in the log showed:
[2016.09.13-10.47.30:672][731]LogWindows:Error: Assertion failed: !IsAsyncBuilding() [File:D:\Build++UE4+Release-4.13+Compile\Sync\Engine\Source\Runtime\Engine\Private\HierarchicalInstancedStaticMesh.cpp] [Line: 2564]

I have no idea what is that!

It appeared fine in editor but crashed during play. Can someone point to what is wrong? Is it in the code or HISMC itself?

2

It appears that constructor doesnt like multiple instances of HISMC. I have to shift it to OnConstruction function. The below code is the solution.

void AHISMCSpawner::OnConstruction(const FTransform& Transform) {
Super::OnConstruction(Transform);
UE_LOG(LogTemp, Warning, TEXT("OnConstruction ZZ "));

MountainSpawner->ClearInstances();
for (int32 a = 0; a < 10; ++a) {

	FRotator rot = FRotator(0, FMath::RandRange(0, 360), 0);
	FVector loc = FVector(FMath::RandRange(0, SurfaceWidth*MapScale), FMath::RandRange(0, SurfaceHeight*MapScale), FMath::RandRange(-200, 0));
	int32 XYScale = FMath::RandRange(5, 12);
	FVector scale = FVector(XYScale, XYScale, XYScale);
	MountainSpawner->AddInstance(FTransform(rot, loc, scale));
}
}