Indirect 3D Scanning of the Foot Plant - Comparison Between a Medium and Low-Cost Tools.

The direct or indirect 3D scanning of the foot's plantar region can be used to manufacture customized insoles, orthosis and orthopedic shoes. The equipments that enable an efficient direct scanning are, in most cases, expensive and inaccessible to professionals. The inability to use such equipment, leads to recourse to indirect scanning with low-cost tools to generate the digital model. In this context, the aim of this study is to compare dimensionally the physical model with two virtual 3D models, one generated by a medium-cost equipment (MDX-40) and the other generated by a low-cost (Memento). To accomplish this goal a model in plaster of the plantar region of a healthy subject was made and later scanned by both methods. Five (5) regions or features of the plaster model were identified and measured. The dimensions were also virtually measured in a 3D CAD environment, in both scanned models. The methodology allowed to conclude that the 3D scanning made by MDX-40 presented a relative error of 0.72% compared to plaster model, while the Memento showed a relative error of 2.85%. In addition, the 3D scanning made by MDX-40 lasted 48 times longer than the Memento process. In view of the difference in cost and time for 3D scanning, the Memento can be considered more viable and interesting than the MDX-40, however, one study is necessary to evaluate the influence of the relative error in the quality of customized insoles.