DWG (from drawing) is a proprietary[3] binary file format used for storing two- and three- dimensional design data and metadata.

It is the native format for several CAD packages including DraftSight, AutoCAD, ZWCAD, IntelliCAD (and its variants), Caddie and Open Design Alliance compliant applications.

DWG (denoted by the .dwg filename extension) was the native file format for the Interact CAD package, developed by Mike Riddle in the late 1970s,[4] and subsequently licensed by Autodesk in 1982 as the basis for AutoCAD.

[5][6][7] From 1982 to 2009, Autodesk created versions of AutoCAD which wrote no fewer than 18 major variants of the DWG file format,[8] none of which is publicly documented.

This function was supported by an encrypted checksum and product code (called a "watermark" by Autodesk), written into DWG files created by the program.

[17] AutoCAD would pop up a message, warning of potential stability problems, if a user opened a 2007 version DWG file which did not include this text string.

[21] Nine days later, Autodesk's attorneys won a broad and deep temporary restraining order against the Open Design Alliance.

The effect of the temporary restraining order and subsequent consent decree was to render the Open Design Alliance's DWGdirect libraries, from one point of view, incapable of creating DWG files that are 100% compatible with AutoCAD Unsubstantiated claim.

[23] Others point out that the failure of "100% compatibility" means only that loading such a drawing triggers an essentially irrelevant warning message when the file is opened in AutoCAD.

In September 2007, Autodesk responded, claiming that DWG has gained a "secondary meaning," separate from its use as a generic file format name.

[37] In early 2007, Autodesk petitioned the USPTO to cancel the Open Design Alliance's "OpenDWG" trademarks, claiming that they had been abandoned.

[39] In 2008, Autodesk sued SolidWorks in US District Court, arguing that through its marketing efforts, the term "DWG" has lost its original generic meaning and taken on a secondary meaning referring specifically to Autodesk's proprietary drawing file format, and therefore any use of "DWG" in competitive products amounted to trademark infringement.

But the LibreDWG library, offered under the GNU GPLv3, could initially not be used by most targeted FOSS graphic software, such as FreeCAD, LibreCAD and Blender, because of a GPLv2/GPLv3 license incompatibility.