A Declarative System to Design Preliminary Surfaces

B-Spline and NURBS surfaces are most often considered to model objects. The object shape is designed by manipulating several control points, which is often very complex and tedious. The declarative approach of surface modelling is a fast and easy way to obtain sketches of parametric surfaces. The designer provides a description of the shape he/she wants to obtain. The semantic extracted from this description is structured through XML language. As a result, a set of parametric surfaces corresponding to the given constraints and features is proposed to the user. This approach is specially devoted to speed up the preliminary design process. This paper introduces our system as a high level tool of surface modelling. Details dealing with the different models and processing involved in our system are proposed. The document is illustrated by the first results of our research study.