enable the designer to quickly explore a great number of spatial solutions. INTRODUCTIONSince the early 80's CAD tools have provided us with a new means of graphic representation in architecture. Contrary to the usual manner in which spatial forms are represented in a 2D "glance" [in sections, elevations and 3D model "constructed" by the computer. Admitting that graphic figuration plays a key role in architecture (Lebahar, 1983) (Boudon et al., 1994) these recent developments constitute an important milestone in the practice of conceptualisation. In fact today's computer techniques provide architecture with a unique opportunity for "retooling" and "re-thinking" its methodologies just as happened with the arrival of perspectives and stereometric projections. 3D model software [Catia, Maya, etc.] In this paper, we make the assumption that a shape modelling process can rely on the application of a set of morphological operators to initial shapes. We refer to several researches which have attempted to identify such operators. We also attempt to validate this design approach through the analysis of some buildings. A design system based on the combination of these operators could

In the early stage of creation, the architect tests his work hypotheses by making many adjustments while designing. During the sketching phase, the existing modeling tools are not compatible with the iterative nature of this process. So the challenge lies in the definition of a model which will allow the whole creative process with its various trying and going back during the phase of conception. We will illustrate this model by implementing a parametric operator allowing the action of folding. Its parametric specificity will enable the architect, in the design phase, to make the numerous moves and returns required to obtain an optimal shape.

In this paper, we make the assumption that a shape modelling process can rely on the application of a set of morpho-semantic operators to initial shapes. In this paper, we will refer to several researches which have attempted to identify such operators.We will attempt to validate this concept through the analysis of some "innovative" buildings. Thus, in different projects of contemporary architects, we can find the trace of some transformations (e.g. "twist", "merge", "overlay", etc.) recorded in the final geometry. These transformations have a symbolic representation. A design system based on the combination of these operators could enable the designer to quickly explore a great number of spatial solutions.

During the creative phase, the architect introduces hypotheses and validates them by trying out various adjustments during the process of conception. The use of existing CAD tools during the conception phase is not compatible with the iterative aspect of this process. So the challenge is to define a model that takes into account the entire creative process in a trial and error framework during the conceptual phase. In this article we will define the "pleating" operator.

In the early stage of creation, the architect tests his working hypotheses by making many adjustments while designing. During the sketching phase, the existing modelling tools are not compatible with the iterative nature of this process. So the challenge lies in the definition of a model which will allow the whole creative process with its various coming and going during the phase of conception. In this article, we are going to define a data structure model allowing the simultaneous exploration of several possible solutions, which seems more in line with a creation process.