The data model refers to the declaration, structure, and handling of types, data, and changes on data within FrooxEngine. The data model allows for change detection, value synchronization, unified structure, and serialization of any and all types that FrooxEngine encounters.
Elements
Everything that gets managed by the data model in some fashion implements the IWorldElement interface. This interface assigns elements with a host of properties, including a reference ID, possible parent element, and whether the element is persistent or not.
This interface doesn't have much behavior by itself--it only specifies a thing as being able to be saved and loaded into worlds in some fashion. More complex behaviors offered by the data model are provided by types that implement this interface. The three types of elements that directly implement this interface are sync elements, workers, and worlds.
Sync elements
Sync elements represent a value or object that can be written to, linked, and send/receive change events from other elements. Sync elements mainly comprise of fields and various types of collections--usually any type name that starts with Sync derives from a sync element.
The main thing that separates sync elements from other elements is, well, synchronization. Whenever a sync element is changed, spare few exceptions like RawOutput<T>, it and its entire parent hierarchy propagate a change event. This includes the elements getting put in the world's update manager to synchronize their values at the end of the update loop.
Workers
World
Each instance
Strict exclusivity
The data model can only function without issue when everyone in a session agrees on what the data model should be. This is the reason why plugins marked as a core assembly type cause incompatible sessions with those who do not have the plugin.