Editing AutoCAD DXF

{{Short description|CAD software interoperability file format}}
{{More citations needed|date=October 2012}}
{{Infobox file format
| name = Drawing Interchange Format
| icon =
| logo =
| screenshot =
| caption =
| extension = .dxf
| mime = image/vnd.dxf
| type code =
| uniform type =
| magic =
| owner = [[Autodesk]]
| released = {{start date and age|1982|12}}
| latest release version = u19.1.01.
| latest release date = {{start date and age|2007|01}}<ref>{{cite web |title=DXF specifications |url=http://images.autodesk.com/adsk/files/autocad_2012_pdf_dxf-reference_enu.pdf}}</ref>
| genre = [[CAD data exchange]]
| container for =
| contained by =
| extended from =
| extended to =
| standard =
| url =
}}

'''AutoCAD DXF''' ('''Drawing Interchange Format''', or '''Drawing Exchange Format''') is a [[computer-aided design]] (CAD) data [[file format]] developed by [[Autodesk]]<ref>{{cite web |url=http://www.faqs.org/faqs/graphics/fileformats-faq/part3/section-45.html |title=FAQS.org}}</ref> to enable [[CAD data exchange]] and interoperability between AutoCAD on different [[computing platform]]s.<ref name=":0"/>

== History ==
DXF was introduced in December 1982 as part of AutoCAD 1.0, and was intended to provide an exact representation of the data in the AutoCAD native file format, DWG (Drawing). For many years, Autodesk did not publish specifications, making correct creation of DXF files difficult. Autodesk now publishes the incomplete<ref name=":0">{{cite web |last1=Moitzi |first1=Manfred |title=What is DXF? |url=https://ezdxf.readthedocs.io/en/stable/concepts/dxf.html |website=/ezdxf.readthedocs.io |publisher=Manfred Moitzi |access-date=27 October 2023}}</ref> DXF specifications online.

== Compatibility ==
Versions of AutoCAD from Release 10 (October 1988) and up support both American Standard Code for Information Interchange ([[ASCII]]) and [[Binary file|binary]] forms of DXF.<ref>{{Cite book|last=Schoonmaker|first=Stephen J.|url=https://www.worldcat.org/oclc/54090798|title=The CAD guidebook: a basic manual for understanding and improving computer-aided design|date=2003|publisher=Marcel Dekker|isbn=0-8247-4569-8|location=New York|oclc=54090798}}</ref>{{Rp|page=59}} Earlier versions support only ASCII.

As AutoCAD has become more powerful, supporting more complex object types, DXF has become less useful. Certain object types, including [[ACIS]] solids and regions, are not documented. Other object types, including AutoCAD 2006's dynamic blocks, and all of the objects specific to the [[vertical market]] versions of AutoCAD, are partially documented, but not well enough to allow other developers to support them. For these reasons many CAD applications use the [[.dwg|DWG format]] which can be licensed from Autodesk or non-natively from the [[Open Design Alliance]].

DXF files do not directly specify the units of measurement used for its coordinates and dimensions. DXF files have a HEADER section where a $INSUNITS variable may specify the intended unit (e.g., 1 for inches, 4 for millimeters). However, not all DXF files contain this information, and some software ignores it.

Most CAD systems and many vector graphics packages support the import and export of DXF files, notably [[Adobe Inc.|Adobe]] products, [[Inkscape]], and [[Blender (software)|Blender]]. Some CAD systems use DXF as their native format, notably [[QCAD]] and [[LibreCAD]].

== 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>

== Criticism ==
Because comprehensive documentation does not exist,<ref name=":0"/> consideration is often given to alternative [[open file format]]s such as Scalable Vector Graphics ([[SVG]], defined by the [[World Wide Web Consortium]] (W3C)), [[Design Web Format]] (DWF, defined by Autodesk<ref>{{cite web |title=DWF files |url=https://www.adobe.com/creativecloud/file-types/image/raster/dwf-file.html |website=adobe.com |publisher=Adobe 2023 |access-date=27 October 2023}}</ref>), or even [[Encapsulated PostScript]] (EPS, [[International Organization for Standardization]] (ISO) and [[International Electrotechnical Commission]] (IEC) standard 29112:2018). DXF (and [[DWG]]) is still a preferred format for CAD files for use by the ISO.<ref>{{cite web |title=ISO Central Secretariat requirements - FAQ for graphics (formats and files) |url=https://www.iso.org/files/live/sites/isoorg/files/archive/pdf/en/grph_faq.pdf |website=iso.org |publisher=ISO 2002 |access-date=27 October 2023}}</ref>

== References ==
{{Reflist}}

== External links ==
{{Commons category|DXF file format}}
* [http://www.autodesk.com/techpubs/autocad/acadr14/dxf/ AutoCAD DXF Reference (from Release 14, 1998)] ([http://images.autodesk.com/adsk/files/autocad_2012_pdf_dxf-reference_enu.pdf PDF version from 2012])
* [https://www.fileformat.info/format/dxf/egff.htm AutoCAD DXF File Format Summary].
* [http://www.autodesk.com/techpubs/autocad/acadr14/dxf/symbol_table_example_al_u05_b.htm Annotated example DXF file] {{Webarchive |url=https://web.archive.org/web/20170106191202/http://www.autodesk.com/techpubs/autocad/acadr14/dxf/symbol_table_example_al_u05_b.htm |date=January 6, 2017}}
* [https://viewer.autodesk.com AutoDesk Online DXF File Viewer].

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[[Category:1982 introductions]]
[[Category:AutoCAD|DXF]]
[[Category:Autodesk products]]
[[Category:CAD file formats|DXF]]