39 3D Model of the Human Body Generated within Pro/Engineer Environment Gergana Nikolova, Liliya Stefanova, Yuli Toshev Institute of Mechanics, 1113 Sofia 1. Introduction Knowledge of geometric (lengths, widths, circumferences, angles) and mass-inertial characteristics of the segments of the human body is of key importance in human motion analysis. Under “motion analysis” we understand not only the analysis of human walk characteristics and parameters (i.e. the application of action forces, the imposture of walk limitations, mass center position, body trajectory, body particular segments etc.) but also the set of modern problems of realistic computer animation and numerical simulation of motion. Human motion analysis is of specific importance for areas such as simulation of the human behavior in space and in sports, design of impact protective transport systems, criminology, ergonomics, etc. Motion data can also be used in anthropomorphic robotics and medicine (orthopedics, traumatology, orthotics and prosthesis design). Besides the analysis of natural motion, the study of the joint functioning of human segments and orthopedic device also proves to be important for prosthetic design and orthotics, whereas an orthopedic device should have an appropriate geometry and suitable mass distribution. Body parameters can be estimated in a number of different ways, including regression equations (C h a n d l e r et al. [1]), C l a u s e r et al. [2]), body segment modeling as series of geometric solids (H a n a v a n [3], H a t z e [4]), employment of medical imaging techniques /computerized tomography, magnetic resonance imaging/ (M u n g i o l e, M a r t i n [5]) etc. Note however that the 3D models designed by using imaging techniques are not mobile, i.e., they do not change their shape in the course of time. Yet, considering a number of kinematical and dynamic biomechanical problems, mobility proves to be necessary. There are many approaches for the design of a solid model, providing БЪЛГАРСКА АКАДЕМИЯ НА НАУКИТЕ . BULGARIAN ACADEMY OF SCIENCES ПРОБЛЕМИ НА ТЕХНИЧЕСКАТА КИБЕРНЕТИКА И РОБОТИКАТА, 55 PROBLEMS OF ENGINEERING CYBERNETICS AND ROBOTICS, 55 София . 2005 . Sofia