I cannot believe... Code: The type or member 'The type or member 'SerializableBoundingSphereD' is prohibited It's in the VRage.Serialization namespace. And yet, SerializableBoundingBo in the VRage namespace is perfectly fine to use. I'm probably asking you to poke a stick in a hornets nest to look at that one. Surely there is a better way for me to serialise some data into binary using the game's existing base `Serializable` classes and structs rather than copying them to my own project? --- Automerge --- Please see if you can add it to the whitelist.