Interoperability in practice: geometric data exchance using the IFC standard

The exchange of information between the different organisations and individuals involved in the different stages of a building's life cycle has always been an important, but at the same time a difficult task. A vast number of participants with different views of the same physical structure have to interact and exchange information through the whole building life cycle. In order to find remedies to the current problems, in particular in CAD data exchange, the product modelling and information exchange standards community have developed several high level representations of buildings (known as Building Information Models - BIMs) in order to enable a more coherent exchange of data. Recently the Industry Foundation Classes (IFC), with a considerable number of software implementations, have emerged as the leading solution candidate. But soon after the first implementations doubts have been raised whether claimed IFC specification compliance by a software product insures a sufficient level of interoperability in practical data exchange. In the presented research work the interoperability performance of three widely used IFC compatible architectural design applications has been evaluated. Tests with file based geometry exchange confirmed our anticipations that the IFC interfaces did not work as expected. The tests demonstrated through illustrative (simple and complex) examples revealed several cases of information distortion and/or information loss both on the entity and attribute level. Unsatisfying model handling proved to be characteristic of all the tested exchange scenarios. Our conclusion is that in the future more effort should be put into the IFC interface development.