Summary: 1 INTRODUCTION
There are a growing number of versions of IFC
(Industry Foundation Classes) data with the annual
release of IFC models by the IAI (International
Alliance for Interoperability). Currently, there are
three major IFC versions (IAI 2002) which are being
utilized in software products (1.5.1, 2.0, and 2.X).
With each progression of IFCs we can expect more
versions to be in use, and a growing number of
software products supporting different versions.
Given the current size of the IFC model (around 600
distinct classes and types), and the fact that it will
grow over time, it is clear that defining a mapping
between one version and the next is a major
undertaking. However, it is imperative that this is
accomplished as data will need to be moved between
the different versions supported by the different
design tools, and data stored in older IFC versions
should be able to be migrated to the newest version.
The fact that a new IFC version builds upon the