.dgn

What is a .dgn file?

Bentley MicroStation's native format — civil engineering and infrastructure.

Safe format
Type Cad
By Bentley Systems (originally Intergraph)
MIME application/octet-stream

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What is it

DGN is the native file format for Bentley MicroStation, a CAD platform used primarily in civil engineering, transportation infrastructure, utilities, and plant design. If AutoCAD dominates architecture, MicroStation owns roads, bridges, railways, and power grids.

The format has been through two major versions: DGN v7 (Intergraph's original format, fixed-record binary) and DGN v8 (based on OGC's GeoPackage-like structure, supporting unlimited levels, multiple models, and true database-style element storage). V8 DGN files can store 2D/3D geometry, cell libraries, reference attachments, rendering materials, and project metadata. The format also supports geospatial coordinate systems natively — crucial for infrastructure projects that span kilometres.

DGN competes directly with DWG in the AEC (Architecture, Engineering, Construction) market. In practice, the division is often geographic and disciplinary: North American architects tend toward AutoCAD/DWG, while European and Asian infrastructure projects frequently use MicroStation/DGN. Government transportation departments (DOTs) in several US states mandate DGN for highway design deliverables.

Technical details
Full Name
MicroStation Design File
MIME Type
application/octet-stream
Developer
Bentley Systems (originally Intergraph)
Magic Bytes
08 09 FE 02 (v7) / D0 CF 11 E0 (v8)
Safety
.dgn is a known, safe format.
What opens it
MicroStation
Subscription Windows
Bentley View
FREE Windows
OpenRoads Designer
Subscription Windows
FME (conversion)
License Win / Mac / Linux
FAQ
Can I open DGN files in AutoCAD?
AutoCAD can import DGN files, but the conversion isn't always perfect — complex elements, cell libraries, and reference attachments may not translate cleanly. Bentley View is a free viewer for native DGN viewing.
What's the difference between DGN and DWG?
Both are CAD formats. DGN is MicroStation's native format, strong in civil/infrastructure. DWG is AutoCAD's native format, dominant in architecture. They serve similar purposes in different markets.
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