History of the Open Design Alliance

The Open Design Alliance (ODA) is a member-driven, nonprofit organization dedicated to the promotion of open industry-standard formats for CAD. First established in 1998, it now has over 1000 members in 40 countries. Major milestones include:
Launch of Teigha® as the new name for the ODA software development platform for CAD and other technical graphics applications. The Teigha brand encompasses all products and is the unifying concept for an environment that goes far beyond the reading and writing of .dwg and .dgn files. Teigha enables ODA members to quickly design and build applications for their customers.
Platform availability was expanded to include .NET support for DWGdirect (now known as Teigha for .dwg files). HOOPS and RedSDK integrations were completed, providing easy access to third-party high performance rendering solutions.
Introduction of DRX (now known as TX), a development platform that allows end-users to create extensions for DWGdirect-based applications. Under the 3rd party component strategy ACIS support from Spatial Technology was integrated with the ODA platform and made available as an optional component for 3d solids support.
Launch of beta release of DGNdirect (now known as Teigha for .dgn files) based on the ODA platform. 
Architecture support was integrated into the ODA platform, allowing member applications to read, create, render, and manipulate custom architectural objects.
In October the OpenDWG Alliance was renamed Open Design Alliance to reflect its wider mission — after an agreement with Bentley® Systems to support the OpenDGN standard. Platform availability was expanded to include ActiveX support for DWGdirect (now known as Teigha for .dwg files).
Introduction of a new software platform called DWGdirect (now known as Teigha for .dwg files). DWGdirect introduced a modern, powerful, and extensible programming interface with far more capabilities than the original OpenDWG Toolkit/Viewkit (now known as Teigha Classic Toolkit/Viewkit for .dwg files), with support for Microsoft® Windows® and most major UNIX platforms.
Incorporation in February of the "OpenDWG Alliance" as an independent, non-profit corporation dedicated to making the .dwg file format an open, accessible standard for storage of drawing data. The new body was formed by a number of companies, led by Visio Corporation.
Committed to the development of software for reading and writing .dwg files, the OpenDWG Alliance set out to make the OpenDWG Toolkit and Viewkit (based on the former MarComp AUTODIRECT libraries) available to all of its members. It began to maintain the OpenDWG library and publish the OpenDWG file specification. The OpenDWG library is now known as Teigha Classic for .dwg files.
Pre 1998
Seeing the need for read and write access to .dwg files as a market opportunity, a number of companies interpreted the .dwg files 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.
By 1997, MarComp had risen to prominence as the leading maker of programming toolkits for accessing .dwg files. In January 1998, MarComp was acquired by Visio Corporation, now part of Microsoft® Corporation.