A method for automated design of orthotic and prosthetic devices has been developed. The method includes scanning a three dimensional model of the patient's limb with a laser scanner. The model is loaded into a computer for use in manufacturing an orthotic or prosthetic device. Before the model is used, it is modified by reducing the overall volume of the model by up to twelve percent of the total volume. Also the model's distal end length is reduced by a calculated percentage of the thickness of a prosthetic liner to be worn with the prosthetic device.