FManagedArrayCollection* Collection(NewObject()); Collection->AddElements(10, "GroupBar"); // Create a group GroupBar and add 10 elements. Collection->AddAttribute("AttributeFoo", "GroupBar"); // Add a FVector array named AttributeFoo to GroupBar. TManagedArray& Foo = Collection->GetAttribute("AttributeFoo", "GroupBar"); // Get AttributeFoo for (int32 i = 0; i <Foo.Num(); i++) { Foo[i] = FVector(i, i, i); // Update AttribureFoo's elements }