Editing AutoCAD DXF (section)

== File structure ==
ASCII versions of DXF can be read with any [[text editor]]. The basic organization of a DXF file is as follows:<ref>{{cite web |url =http://www.autodesk.com/techpubs/autocad/acadr14/dxf/dxf_file_structure_al_u05_b.htm |title=DXF File Structure}}</ref>

; {{code|HEADER}} section: General information about the drawing. Each parameter has a variable name and an associated value.
; {{code|CLASSES}} section: Holds the information for application-defined classes whose instances appear in the {{Code|BLOCKS}}, {{Code|ENTITIES}}, and {{Code|OBJECTS}} sections of the database. Generally does not provide sufficient information to allow interoperability with other programs.
; {{code|TABLES}} section: This section contains definitions of named items.
# Application ID ({{Code|APPID}}) table
# Block Record ({{Code|BLOCK_RECORD}}) table
# Dimension Style ({{Code|DIMSTYLE}}) table
# Layer ({{Code|LAYER}}) table
# Linetype ({{Code|LTYPE}}) table
# Text style ({{Code|STYLE}}) table
# User Coordinate System ({{Code|UCS}}) table
# View ({{Code|VIEW}}) table
# Viewport configuration ({{Code|VPORT}}) table

; {{Code|BLOCKS}} section: This section contains Block Definition entities describing the entities comprising each Block in the drawing.
; {{Code|ENTITIES}} section: This section contains the drawing entities, including any Block References.
; {{Code|OBJECTS}} section: Contains the data that apply to nongraphical objects, used by [[AutoLISP]], and [[ObjectARX]] applications.
; {{Code|THUMBNAILIMAGE}} section: Contains the preview image for the DXF file.
; {{Code|END OF FILE}}

The data format of a DXF is called a "tagged data" format, which "means that each data element in the file is preceded by an integer number that is called a group code. A group code's value indicates what type of data element follows. This value also indicates the meaning of a data element for a given object (or record) type. Virtually all user-specified information in a drawing file can be represented in DXF format."<ref>"Chapter 1 -- DXF Format" [http://www.autodesk.com/techpubs/autocad/acad2000/dxf/dxf_format.htm Autodesk.com]</ref>