OpenDWG History

The Open Design Alliance is committed to the development of libraries for reading and writing DWG files, making the DWG file format an open standard for storage and exchange of CAD data. To achieve these goals, the Open Design Alliance develops OpenDWG and maintains and publishes its file specification.

Early DWG Access

Seeing the need for read and write access to DWG files as a market opportunity, a number of developers took it upon themselves to reverse-engineer the DWG file format, enabling them to produce programming toolkits, file viewers, and other add-ons for Autodesk® AutoCAD®. These companies included Cimmetry Systems, Cyco, Kamel Software, MarComp, Sirlin, and Softsource. From 1990 to 1997, MarComp rose to prominence as the leading maker of programming toolkits for accessing DWG files. MarComp produced these toolkits using a black box technique, laboriously creating one test drawing after another with AutoCAD and determining how the files changed with changes in the drawing. Over time, MarComp continued to adapt and extend AUTODIRECT to support eight consecutive versions of AutoCAD drawing files — versions 2.5, 2.6, 9, 10, 11, 12, 13 and 14, as well as the several minor revisions made by Autodesk during the life of AutoCAD Release 13. MarComp's AUTODIRECT took an innovative approach to DWG access by incorporating the ability to read both DWG and DXF in one package, and by "resolving" all files. Sensing the need to bring this technology in house, Visio Corporation (now part of Microsoft® Corporation) acquired MarComp in January 1998.

Forming the OpenDWG® Alliance 

Visio Corporation determined that the DWG format should become an open standard, with multiple vendors able to read and write these files without fear of data loss. In February 1998 it formed with a number of companies the OpenDWG Alliance, an independent non-profit corporation dedicated to making DWG an open, accessible standard for storage of drawing data. Since its founding, the OpenDWG Alliance made the OpenDWG Toolkit and Viewkit (based on the former MarComp AUTODIRECT libraries) available to all of its members. In 2002, the OpenDWG Alliance introduced a completely new set of libraries — DWGdirect — written from the ground-up in object-oriented C++. In 2003, the OpenDWG Alliance changed its name to Open Design Alliance.

OpenDWG Today

The Open Design Alliance continues to promote open industry-standard formats for CAD data now and in the future. The ODA maintains and updates the OpenDWG file specification regularly to accommodate changes in the DWG file format. With thousands of ODA members employing the use of ODA software libraries in their own applications, OpenDWG will continue to be a robust, reliable, and accepted standard for the storage and exchange of CAD data.