Lawrence Berkeley National Laboratory

The Industry Foundation Classes (IFC) model of the International Alliance for Interoperability (IAI)-an object data model of buildings-is in its seventh year of development. The last three releases of the model (IFC 1.5.1, 2.0 and 2x) have been implemented by a number of "mission critical" industry applications. The deployment of such software in real life projects is just starting. The author is exploring lessons from early deployment that are related to end user and general industry readiness for software interoperability, project model population with data and issues with compatibility of project data, built-in limitations in applications and in the data model, exchange file size and the selection of interoperable software for a project, as well as benefits attainable today from the use of interoperable software. He concludes that software interoperability is beginning to work in this industry, although not as smoothly as first expected.