This paper proposes a prototype architectural design environment which aims to integrate various applications for designing a building. Within an object-oriented design environment, a core data model and a data management system have been implemented to seamlessly connect all applications. The process of design has been investigated with the purpose of characterising the role that a system of this kind may have. In defining the system, an approach has been used that privileges the relationships with the existing computer-aided design (CAD) tools based on data exchange standards in course of definition today.