Product Modelling is considered to be an established concept not only for semantically based data exchange, but also for the specification of models, dealing with specific application requirements. The product model approach is regarded to be one step towards a new generation of Computer Aided Architectural Design, and to provide underlying means for enabling communication between different applications on a semantic level. After on overview about the background and the basis principles of product modelling, the authors discuss how product models can be used in commercial developments and in applied research projects.