The following terms help to further define the DataGroup System concept:

• Catalog Type - Any Building object having attached data that you and the application can recognize, control, manipulate, and schedule. Catalog types are defined by the application and by the user, within application and user defined definitions.
• Catalog Item - Any Building predefined subclassification of an object. A catalog item predefines some or all of the instance data applied when a particular object is placed.
• Instance Data - Information that is attached to, and unique to, any given catalog item instance in a model (within a 2D or 3D file). Instance data identifies a catalog item, known to and defined by the application and/or the user. Instance data attributes can be edited on individual catalog item instances.
• Application Properties - Property attributes that are controlled by the application and used to define application catalog items. This includes data that drives and is driven by geometric properties (e.g. wall height determines the physical geometry of a wall) and not user attribute data that is independent of geometry.
• User Properties - Property attributes that are controlled by the user and employed exclusively to carry information for tracking and reporting. This data is not normally leveraged by the application.