A system for three-dimensionally modeling and restitution a subject, the system comprising a housing suitable for being carried in the hand by an operator, the housing having an optical unit with stereoscopic digital video cameras co-operating with an inertial navigation unit having a trihedron of optical fiber gyros and a trihedron of accelerometers for generating position and displacement signals in a frame of reference. The housing may also include, in particular, a telemeter laser, an infrared video camera, a GPS unit, inclinometers, and tri-flux magnetometers. A second subassembly connected to the housing by an optical and/or electrical connection cable contains an electrical power supply, electronic circuits, and a microcomputer for processing signals delivered by the housing and for generating a three-dimensional model of the subject, implementing a photogrammetric technique.