Perform Frustum Check

[TooManyCrashes]

You can do it like this:

bool IsInFrustum( AActor* Actor)
{
	ULocalPlayer* LocalPlayer = GetWorld()->GetFirstLocalPlayerFromController();
	if (LocalPlayer != nullptr && LocalPlayer->ViewportClient != nullptr && LocalPlayer->ViewportClient->Viewport)
	{
		FSceneViewFamilyContext ViewFamily(FSceneViewFamily::ConstructionValues(
			LocalPlayer->ViewportClient->Viewport,
			GetWorld()->Scene,
			LocalPlayer->ViewportClient->EngineShowFlags)
			.SetRealtimeUpdate(true));

		FVector ViewLocation;
		FRotator ViewRotation;
		FSceneView* SceneView = LocalPlayer->CalcSceneView(&ViewFamily, ViewLocation, ViewRotation, LocalPlayer->ViewportClient->Viewport);
		if (SceneView != nullptr)
		{
			return SceneView->ViewFrustum.IntersectSphere(
						Actor->GetActorLocation(), Actor->GetSimpleCollisionRadius());
		}			 
	}

    return false
}