AutoCAD® 2002 - Autodesk

Extension Dictionary and Persistent Reactors
The extension dictionary is an optional sequence that stores the handle of a
dictionary object that belongs to the current object, which in turn may contain
entries. This facility allows attachment of arbitrary database objects to
any database object. Any object or entity may have this section.
Persistent reactors are an optional sequence that stores object handles of
objects registering themselves as reactors on the current object. Any object or
entity may have this section.
Extended Data
Extended data (xdata) is created by AutoLISP or ObjectARX applications. If
an entity contains extended data, it follows the entity’s normal definition
data. The group codes 1000 through 1071 describe extended data. The following
is an example of an entity containing extended data in DXF format.
Normal entity definition data:
0
INSERT
5
F11
100
AcDbEntity
8
TOP
100
AcDbBlockReference
2
BLOCK_A
10
0.0
20
0.0
30
0.0
Extended entity definition data:
170 | Appendix B Advanced DXF Issues