Behaviour in Synthetic Entities Ronald Kruk CAE Electonics Montréal, P.Q. Canada Abstract Elements of the development of realistic performance and behaviour in the synthetic entities (players) supporting modeling and simulation (M&S) applications are described. Particular attention is paid to military training with modern human-in-the-loop (virtual) training systems that incorporate sophisticated synthetic environments, which provide: 1. The operational environment, including, for example, terrain databases; 2. Physical entity parameters which define performance in engineered systems, such as aircraft aerodynamics; 3. Platform/system characteristics such as acoustic, IR and radar signatures; 4. Behavioural entity parameters which define interactive performance, including knowledge/reasoning about terrain, tactics; and, 5. Doctrine, which combines knowledge and tactics into behaviour rule sets. The resolution and fidelity of these model/database elements can vary substantially, but as synthetic environments are designed to be composeable, attributes may easily be added (e.g., adding a new radar to an aircraft) or enhanced (e.g. Amending or replacing missile seeker head/ ECM models to improve the realism of their interaction). To a human in the loop with synthetic entities, their observed veridicality is assessed via engagement responses (e.g. effect of countermeasures upon a closing missile), as seen on systems displays, and visual (image) behaviour. The realism of visual models in a simulation (level of detail as well as motion fidelity) remains a challenge in realistic articulation of elements such as vehicle antennae and turrets (with human figures - posture, joint articulation), but currently this is more dependant upon the quality of the models driving those entities than graphics processing power per Se. A modern synthetic environment system is applied to illustrate some of these elements and concepts, and then to demonstrate how they are assembled into a simulation.