Open DWG File

Drawing Exchange Format (DXF)

DXF is a CAD exchange format introduced by Autodesk in 1982 as part of AutoCAD 1.0. Latest released version of DXF was 28.1.01 and it was shipped with AutoCAD 2014. DXF was introduced as an open source analogue of DWG file format to be used for CAD data exchange between AutoCAD and other software and hardware.

DXF functionality has certain limitations in comparison to DWG but because of being open source DXF is supported by many different software packages. If you need to use your CAD data in a software other than Autodesk’s, you need to use DXF. If not, use DWG.

DXF files similar to most other CAD exchange file formats take significantly more space than DWG because DWG is stored in binary format and DXF is plain text.

DXF files contains following sections:

• HEADER. Contains information about DXF file, settings and variables associated with DXF file.
• CLASSES. Holds information for application specific classes. Instances of these classes can appear in BLOCKS, ENTITIES and OBJECTS sections.
• TABLES. Contains definitions of named items.
• BLOCKS. Contains an entry for each block entry in the drawing.
• ENTITIES. Contains drawing entities
• OBJECTS. Group codes that apply to non-graphical objects.
• THUMBNAILIMAGE. Preview image of the DXF file.

Objects in DXF format are different from entities. Objects don’t have visual representation and entities do. For example, dictionaries are objects. Entities are referred in DXF as graphic objects and objects are referred as nongraphical objects.

DXF files are transferred over e-mail or internet using following multipurpose internet mail extensions (MIME) types:

• application/dxf
• application/x-autocad
• application/x-dxf
• drawing/x-dxf
• image/vnd.dxf
• image/x-autocad
• image/x-dxf
• zz-application/zz-winassoc-dxf

Alternative formats to DXF are DWG, IGES, STEP.