Abstract

This paper is a study of architectural design process. The explanation of an elementary change of state of the project is faced with two cases : (i) change of state transforms the morphological model, in which case schema operator is needed to describe the design ope- ration (Raynaud, 1999); (ii) change of state does not involve such a transformation and just consists in a size adjustment. The present paper examines the second case onto several examples (Gio Ponti, Sebastiano Serlio, Villard de Honnecourt). It is shown that schema operator is also required to describe the design operation in its entirety. But, since scale is regarded as a design operator by architecturology, the connection between schema and scale must be clarified. The reasons leading to the characterization of scale and schema as design co-operators are reviewed.