DGN is the name used for CAD file format

File format

A file format is a particular way that information is encoded for storage in a computer file.Since a disk drive, or indeed any computer storage, can store only bits, the computer must have some way of converting information to 0s and 1s and vice-versa. There are different kinds of formats for...

s supported by Bentley Systems

Bentley Systems

Bentley Systems, Incorporated is a software company that produces solutions for the design, construction and operation of infrastructure. The company’s software serves the building, plant, civil, and geospatial vertical markets in the areas of architecture, engineering, construction and operations...

' MicroStation

Microstation

MicroStation is a CAD software product for 2- and 3-dimensional design and drafting, developed and sold by Bentley Systems. The latest versions of the software are released solely for Microsoft Windows operating systems, but historically MicroStation was available for Macintosh platforms and a...

 and Intergraph

Intergraph

Intergraph Corporation is an American software development and services company. It provides enterprise engineering and geospatially powered software to businesses, governments, and organizations around the world. Intergraph operates through two divisions: Process, Power & Marine and Security,...

's Interactive Graphics Design System (IGDS) CAD programs.

There are two versions of DGN:

• Up until 2000, all DGN files were based on the Intergraph Standard File Formats
  Intergraph Standard File Formats
  Intergraph Standard File Formats are the file formats common to MicroStation and Intergraph's Interactive Graphics Design System...
  
   (ISFF) specification, published in the late 1980s by Intergraph. Sometimes referred to as V7 DGN, or Intergraph DGN.

• In 2000, Bentley Systems created an updated version of DGN which includes a superset of DGN's capabilities, but which has a different internal data structure than the ISFF-based DGN. This version is properly referred to as V8 DGN.

Although DGN is not as widely-used as Autodesk

Autodesk

Autodesk, Inc. is an American multinational corporation that focuses on 3D design software for use in the architecture, engineering, construction, manufacturing, media and entertainment industries. The company was founded in 1982 by John Walker, a coauthor of the first versions of the company's...

's DWG

AutoCAD DWG

DWG is a binary file format used for storing two and three dimensional design data and metadata. It is the native format for several CAD packages including AutoCAD, IntelliCAD and Caddie. In addition, DWG is supported non-natively by many other CAD applications...

, it is nevertheless mission critical in many large projects, including buildings, highways, bridges, process plants, shipbuilding.

In 2008 Autodesk and Bentley agreed on exchange of software libraries, including Autodesk RealDWG, to improve the ability to read and write the companies' respective DWG and DGN formats in mixed environments with greater fidelity. In addition, the two companies will facilitate work process interoperability between their AEC applications through supporting the reciprocal use of available Application Programming Interfaces (APIs).

External links

• OpenDGN - Bentley's OpenDGN initiative
• Microstation 95/ISFF Description (pdf) - Information on the ISFF/DGN file format as distributed with Microstation 95.
• ISFF Specification - Intergraph Standard File Formats (Element Structure)
• DGNLib - DGNLib: a free Microstation DGN (ISFF) program library
• DGNdirect - DGNdirect, from Open Design Alliance
  Open Design Alliance
  The Open Design Alliance is a nonprofit organization of over 1,200 members in 50 countries which develops Teigha©, a software development platform used to create engineering applications including CAD...
  
  : a V8/V7 DGN program library.