CAD tools for designing shoe lasts for people with diabetes

In the context of a research program aiming at defining a framework to acquire patient data and support the whole shoe design and manufacturing process, this paper presents new CAD tools to design and validate lasts for shoes designed specifically for people with diabetes. Shoe last custom-izing systems have already been proposed in literature. However, tools for designing shoes for peo-ple with diabetes do not currently have the capacity to modify the last in order to reduce the risk of foot ulceration whilst at the same time preserving the style of the shoe. The main contributions of the work are given by a method to identify the required design features to guarantee the footwear preventive function, the determination of a systematic protocol for orienting, and measuring the virtual models of the feet and the lasts, and the definition of geometrical operators to modify the last shape according to its original aesthetic and the required footwear parameters. Such variables are computed by a knowledge based system on the basis of the patient’s pathology. The paper presents the implementation of two CAD tools and describes the procedures and the geometrical algorithms to handle the last geometry. Finally a case study is reported to show the advantages provided by the proposed approach in terms of achieved quality of the design process and expected footwear performance.