IFC 2×4 Alpha Release has been Published for Comments


The IAI (International Alliance for Interoperability) has just released the latest version of the IFC specifications as an Alpha version for discussion. If you have never heard about IFC, then consider this a great file format to exchange object-oriented building information (= entire BIM building models) between various CAD and analysis applications. Most CAD software (e.g. Revit, ArchiCAD) nowadays has the IFC 2×3 specification installed as an export option. With each new release, new features and entire building domains (facilities management, HVAC, GIS etc.) are being added to the format, which will ultimately turn it into a universal file format for all building disciplines.

Although I am still waiting for the timber design specifications to be included, the current version is already immensely useful – not the least for exchanging Revit models across multiple versions of Revit (a very frustrating missing feature). In any case, interesting new features in the IFC specification are:

  • Vertical offsets for walls
  • Composite profiles for structural elements
  • Improved definition of sweeps and tapered object
  • Spatial zones for e.g. thermal or lighting

In particular, the structural changes are:

Structural Elements

Support of profiles (cross section definitions) of columns, beams and similar elements has been enhanced. Section geometry and material information is now associated with building elements in the same fashion as with walls and slabs. References to standards or libraries can now be added to profile definitions, and a number of details in profile definitions have been enhanced. Parts and components, for example insulations, can now be accompanied by type objects like all other building element classes. New classes to provide properties of manufacturing details such as cutouts have been added. The structural analysis domain model has been cleaned up and partially simplified. It is now possible to provide analysis results not only at point connections but also at curve or surface items.

Of course, there’s more. You can read about all changes in the final documentation (click on “What’s New”).