To provide his avatars with realistic-looking gait and body language, Torrens equips actors with markers on their bodies at key vertices and endpoints. As the person acts out different scenarios--walking down the street, taking part in an angry mob, running into a wall--a bank of high-res cameras records the position of the markers (the red circles in the diagram), a technique called motion capture. The computer program interpolates the connections ("edges") between the markers based on human skeletal bones, giving us the movement of the skeletal "rig" through space and time. Once digitized, the avatar's base behavioral data can be manipulated to change its size, speed, and strength.