In architectural design, not only the structure and the form, but also the activity in and around the building is taken into consideration. However, the latter is not represented very often in the design models which are essential in the design process to externalize the designer's ideas. In this paper, we propose an original design model which can represent activity. Through comparison with other two models, ordinary volumetric model and 3D CAD model, the differences among three design models are clarified, in terms of the design process and the resulting spatial configuration.
