In accompaning with increasing aged people, the people who have amputated their knees are now considerably. Although computer technologies have been developed in recent years, main part of work that making prosthesises for people who have lost their parts of bodies such as fingers, arms and legs are dependent on skill and experirnce of workers.

Many of prosthetic parts are designed and made with CAD/CAM systems. Only a few CAD/CAM system can support a socket design and manufacture process of the prosthetics industry. There are many problems to be solved in order to construct a system which can make well suited prostheses in a short time. Problems of reconstructing geometric models of body shapes, smoothing data measured data and rapid prototyping of 3-D models are especially important ones.

A new CAD/CAM system for making below knee prosthetic sockets as the interface between human and artificial legs is presented. This paper describes:

1. A conceptual design of the system,
2. An algorithm for reconstructing geometric models from image data,
3. Measuring device of inner face of a socket.