Reverse engineering of aesthetic products: use of hand-made sketches for the design intent formalization

In the context of styling products development it is well known that sketches are the most immediate and used means for the "external representation" of the industrial designers’ intentions; the designer, however, also needs physical full-scale models in order to evaluate the aesthetic solution. Reverse Engineering (RE) techniques support the transformation of the physical mock-ups in digital ones in order to perform the engineering developments. The observation of the design phases highlights the need to study new methodologies and computer-based tools in order to simplify the RE process and to improve the quality of the final result. The conversion, from real to virtual, can be time-consuming and strongly critical in terms of product aesthetic and functional contents preservation. The process can be affected by several misunderstandings in the communication of the design values from the designer to the product engineers. In this paper we propose a method for the formalization and recognition of the aesthetic properties within the different modes of design representation. The proposed method is based on the examination of the design principles used by the designer during the creative process (aesthetic intentions) and on techniques for the representation of creative ideas. In particular, we analyse the free-hand sketches and drawings to retrieve both the implicit (lines/curves) and explicit information (textual notes). Such information is used to develop a set of rules to support the identification of the styling lines on the points cloud data. The method has been experimented using a commercial CAD system to manage the heterogeneous data (points cloud data, sketches and notes). The preliminary validation process shows good results in terms of timesaving. This is mainly due to two factors: the remarkable simplification of the surface reconstruction phase and the continuous monitoring of the aesthetic coherence