All entities have a number of common properties and include member functions for setting and getting their values. These properties, which can also be set by user commands, are the following:
When you add an entity to a block table record, AutoCAD ® automatically invokes the AcDbEntity::setDatabaseDefaults() function, which sets the properties to their default values if you have not explicitly set them.
AcDbViewport acquires the settings of the current graphics window.
If a property has not been explicitly specified for an entity, the database's current value for that property is used. See Database Operations for a description of the member functions used for setting and getting the current property values associated with the database.