A .rfa file is a family file; a .rvt file is a model file. Each of these files is a database that collects various graphical and non-graphical objects. These objects have different types, sizes, destinations, functionality and specifics. A drawing loaded from a file can contain different information about objects that define the geometry, styles, representations, settings and attached data.

Database

A database serves as a container object for all data and relationships loaded from the file. Objects of the database are organized in collections; each collection contains and manipulates objects of a specific type. Each object can be accessed using its own unique identifier, which is created by an object's database and valid during the lifecycle of the object.

Each database contains the following types of objects:

• Element — An object that usually corresponds to a single building component such as a wall or door, but it can be also an abstract object such as the type of something or a view. Each element has a unique ID.
• Manager — A special container that stores and manages object collections.
• Other objects — Objects that do not have a graphical representation, such as groups, DBDrawings, etc.

Specifically, each database has the following main parts for storing and working with objects:

• ElemTable — Container that keeps all elements. It stores an array of ElemRec items; each ElemRec item contains three parts of the element and element history.
• AppInfoManager — Root manager for database managers. Named managers are used by an application, subroutines, an element's methods to find other elements, get/set settings, and they describe element dependency, etc. Each manager is derived from the OdBmAppInfo class and may contain additional information.
• StyleSettings — Container that keeps predefined tables of predefined built-in parameters (CategoryTable, MaterialTable, PenWidthTableGetter, LinePatternTable, FontTable, FillPatternTable, TilePatternTable, AppearanceAssetTable, StructuralPropertySetTable).
• OwnerFamilyId — ID of the main family in the file, if the database is a family file (.rfa file).
• DevBranchInfo — Container that keeps base information about the file: product, file version, user name, language, information for work sharing, etc.

Element

Elements are stored as an ElemTable inside the database. Each element has three parts:

• ElementHeader — Base, element-independent data, and the pointer to the element class descriptor.
• Element — Data specific to the element. For example, for CurveElement, all data that is used for regenerating geometry and interacting with other database objects is stored in CurveElement which is inherited from Element.
• GElement — Geometry cache (or SerializedDummy if it does not have geometry cache). GElement can contain a set of view-dependent geometries. If it has a set of geometries, GFilter nodes should be used to choose the correct geometry.

See Also

ODA BimRv SDK Database Overview