Development of CAD models from sketches: a case study for automotive applications

Today products are designed not only for their functional requirements but also for aesthetics. In the automotive industries, styling has become a major part of the design process with class-A surfaces. Class-A surfaces are freeform surfaces with a continuous curvature. The process of engineering any component or system begins by generating a concept that actually describes the product in terms of its form, function, and fit. Concept sketches help the designers to arrive quickly and easily at a stage where a satisfactory design can be specified for detailed design. These concept sketches can be used for development of the digital concept design and analysis of the curves and surfaces. Software such as Alias exists and thus can be used with suitable hardware for sketching the concept of the car body on a computer screen. In this paper a systematic procedure is discussed for generating class-A surfaces from the images of concept sketches which are manually prepared on paper. These images are imported into the sketch tracer module of CATIA V5. A designer can use the image as the reference and produce a digital sketch by tracing the image using CATIA V5 software without adding any special hardware. Later, interrogation of these surfaces for improved aesthetics can be attempted. This method will be useful for the users of CATIA V5 to improve their design practices and skills.