||Despite the fact that several sophisticated building product data model proposals and working prototype applications have been developed, actual practical use of product model applications does not, however, seem a viable prospect for the near future. In our view, the key problem impeding a more widespread use of product model applications is that the user has been neglected. The laboratory of Construction Economics and Management at the Helsinki University of Technology has developed a prototype application for renovation architectural design. The approach taken to this work was to design intelligent user interfaces, the use of which resembles as closely as possible traditional and manual document-oriented design methods. The application consists of four elements: the user interface, a building product model database, library database and tools for producing output documents. The application is developed on an AutoCAD system integrated with a relational database management system, Paradox for Windows. The user interfaces were designed using AutoLisp, DCL and ObjectPAL. The extensive use of actual case studies in the development of this prototype application has provided valuable input in that it has allowed continuous testing of the system and further refinements based on real-life experience.