Engine determines best behavior. Currently equivalent to Nonatomic.

The Model and all of its descendants are streamed in/out together. For streaming in, this applies when any descendant BasePart is eligible for streaming in. For streaming out, this applies when all descendant BaseParts are eligible for streaming out.

Persistent models are sent as a complete atomic unit soon after the player joins and before the Workspace.PersistentLoaded event fires. Persistent models and their descendants are never streamed out.

Behaves as a persistent model for players that have been added using Model:AddPersistentPlayer(). For other players, behavior is the same as Atomic. You can revert a model from player persistence via Model:RemovePersistentPlayer().

When a nonatomic model is streamed, descendants are also sent, except for part descendants. Nonatomic models that are not descendants of parts are sent during experience loading.