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How to convert DGN (MicroStation) to COLLADA (.dae)?

PolyTrans|CAD+DCC performs mathematically precise CAD, DCC/Animation, GIS and BIM 3D file conversions into all key downstream 3D packages and file formats. Okino software is used and trusted throughout the world by many tens of thousands of 3D professionals in mission & production critical environments, backed by respectable personal support directly from our core development team.



DGN is a 2D/3D file format, with its roots going back to the early 1980s, that is used as the native file format of such programs as Bentley's MicroStation and Intergraph's PDS software packages. Relative to deep history, DGN could be considered a competitor or rival to the Autodesk DWG file format. Okino considers both DGN and DWG rather "crude" and old file formats, depending on what vintage of file is used and whether the files contain ACIS-SAT/Parasolid "BREP solids" geometry or just 2D/3D vector geometry.

Okino considers a DGN V8 file to be of two varieties: (1) "GIS" like models defined using basic primitives like lines, curves, arcs and 3D objects defined by the extrusion and revolution of these basic elements - these types of files are typically glutted with an enormous number of basic elements which can result in massive scenes that can very slow to display and take up a lot of memory. (2) The second variety of DGN file uses the more modern "BREP solids" geometry type to define the 3D objects as lighter weight and more efficient NURBS surfaces and solids.

Okino spent over 20 years developing its DGN importers and exporters. As such, we understand the nuances of DGN and its related conversion issues. Please refer to our DGN importer WEB page which has extensive information on (1) the history of DGN and when to use DGN, (2) how to import massive DGN files (such as PDMS 3D plants, oil refineries, etc), (3) how to import from AVEVA PDMS and Intergraph PDS, and (4) our suggestions about using STEP or VRML2 as alternative conversion methods from Bentley's MicroStation.



COLLADA (DAE) is a XML-based readable file format of the 2007/2008 era which had an original goal of allowing efficient cross conversion of 3D asset data between all of the major 3D DCC/Animation systems of that era. Many 3D software programs came to implement COLLADA but with varying levels of comformity and data reliability. COLLADA is more generally known as a polygonal mesh file format and not a MCAD/CAD/AEC/GIS format. Today people would usually use FBX over COLLADA, depending on the quality of the associated (and dated?) import/export converters.

Okino created one of the key implementations of the COLLADA file format in its import and export converters. However, it saw little need for them except for exporting into Cinema-4D from 2008 to 2012, as the primary gateway into Google Earth, and as our still-preferred method to move 3D assets into Blender (rather than FBX). COLLADA does have its place in these current and prior times.

Okino has a unique take on the COLLADA file format as Okino was at the very center of the DCC/Animation conversion world. In 2007 Rémi Arnaud and Mark Barnes argued that yet-another 3D file format was required and hence Sony funded their efforts to define COLLADA for the cross conversion of assets between (initially) 3ds Max and Maya. However, what they conveniently ignored was that Okino already had the defacto cross conversion system in place, for the prior decade, based on its BDF (binary data translation file format) for 3ds Max, Maya, Cinema-4D, Softimage, LightWave and others. In the mid 2000's there was a "not invented here" mindset and hence everyone wanted to stamp/force their own 3D file format on the industry: FBX (Autodesk), COLLADA (Sony), 3dxml (Dassault Systems), XAML-3D (Microsoft), U3D (Adobe and Intel), etc. There was little need or reason to have "yet-another" set of new 3D file formats. All, except FBX, would basically come and go as of 2007/2008. The implosion of the DCC/Animation industry of 2005-2007 and the 2008/2009 recession further hampered the long term adoption or need for COLLADA over Autodesk's FBX.

COLLADA is/was a very fine file format but it was really not needed at the time of its introduction in 2007. It only introduced yet-more confusion to the 3D graphics market as to which 3D file format to use to transfer 3D assets between packages. Developers generally implemented v1.4 of the COLLADA file specification then lost interest thereafter.

However, as a saving grace for COLLADA, all of the 3D software packages which had implemented a good COLLADA exporter became instant gateways to move their 3D assets into the then-new glTF file format of the mid 2010s, until such time that these same packages could add in their own glTF exporters.