This paper presents one part of the IVGI (virtual reality for industrial engineering) project, which is concerned to determine optimal operator movement trajectory (path) in the normal and threat environments. Using dynamic programming method, an approach is introduced to fined the optimal trajectory for walking an operator in the workplace by minimising the accumulated movement risk and length. The danger zones are considers as the fuzzy sets, and the risk through the trajectory is evaluated by considering the membership degree of the operator body parts in the danger zone(s), through the all movement sequences. This method can be used to determine the optimal paths through the design processes of the industrial systems.
