Freehand sketches in product development

Product development starts with conceptual design including the concepts for shape and function - the gestaltung. Conceptual designers work on vague and fuzzy data applied to perception modelling and creation of a prototype product model. Within the further constructive product development, working in virtual environments is generally applied and the digital product model in its different stages is an essential prerequisite for manufacturing processes. For some time now, there has been a strong demand to define also the creative human problem solving in conceptual design as a task of virtual product development and to assist the process simultaneously through the use of appropriate virtual methods. This paper reports on R&D results concerned with integration of the process of gestaltung based on traditional aids, such as freehand paper sketches, in virtual environments. For this, a strategy has been developed to interpret product descriptions in freehand sketches and to transfer them to digital threedimensional models, e.g. in order to visualize, calculate and evaluate shapes up to the development of computer-aided design (CAD) models. The implemented prototype software SKIZZERK combines image-based modelling methods with conventional CAD modelling methods.