This section describes how to derive a custom class from OdDbEntity class, and includes specific examples of overriding virtual methods provided by the OdDbEntity class. Overriding common entity operations, such as object snap points, grip points, and stretch points, is also discussed in this section.

OdDbEntity is the base class for all database objects that have a graphical representation. The OdDbEntity class is derived from the OdDbObject class. Creating a custom entity involves the following steps:

Deriving a Custom Entity Class

Implementing Drawing Functions

Implementing Save and Load Functions

Implementing Undo and Redo Operations

Implementing Transformation Functions

Implementing Grip Point Functions

Implementing Snap Point Functions

Implementing Exploding Functions

To learn about the Smiley example code, see Smiley Object Example.