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How to convert IFC (Industry Foundation Classes) to DGN (MicroStation)?

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.



The Industry Foundation Classes (IFC) is a CAD data exchange object-based file format with a data model developed by buildingSMART to facilitate interoperability in the architecture, engineering and construction (AEC) industry, and is a commonly used collaboration format in Building information modeling (BIM) based projects.

IFC files can be written out by such industry standard programs as: ArchiCAD, Allplan, Autodesk's AutoCAD and Revit, Microstation, Tekla Structures, SmartPlant3D and Vectorworks.

Please note: you would always want to use the DWF-3D file format and the Okino DWF-3D file importer to import 3D model data from Autodesk's AutoCAD, Navisworks and Revit, as well as AVEVA's PDMS software.

It is may be safe to say that few 3D graphics users properly understand IFC or why/how it should be used, when it should be used or how it is to be used. In simplistic terms, IFC is NOT a universal data interchange file format like COLLADA, FBX, 3ds, OBJ, DXF, DWG, etc. Rather, IFC is more of an "abstraction" for an architectural model so that BIM companies can exchange IFC files for design iterations without any loss in overall geometric quality. Hence, the basis of IFC is to make an abstract building with stories, floors, doors, columns, windows, etc. From these hang "abstractions" such as 2D plan views and 3D renderable geometric data.

While IFC can be considered a standardized file format by BuildingSmart, not all 3D programs or 3D viewers will "interpret" an IFC file in the same manner due to the abstract nature of the file format and also by the generally loose manner in which a model can be defined and with different contexts and representations.



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.