Motion capture technology originated in the 1970s as medical researchers began to photograph live action as a means of studying biomechanics. The methodology of attaching sensors to living, moving athletes proved instantly valuable for sports coaches, trainers, kinesiologists, physical therapists, and other health care professionals. Today, animators are using the technology to map the physical gestures of real humans and animals that they map against their 3D creations for film, video, and computer games.
With motion capture technology, today's animator does not need to input every action and gesture into an animation frame. The captured angles and positions of the live actor are fed into the computer and the animation software can render movement as well as textures and skins.
Motion capture technology uses both passive and active markers that are attached to the live subject to generate images. Passive markers reflect light back to a bank of cameras that map the overall movement in space. Active optical markers are comprised of light emitting diodes that spark alive as the character moves in a defined space, creating movement-over-time imagery.
The animation artist creates a model for use in the film, video, or game, and then uses software that appends the captured movement from the live figure to the model. The net result is that the model takes on the captured movement, step by step. With the motion capture animation, a director can make decisions on the fly as to where the "actor" stands, moves, and what the character wears. Near-instant backgrounds, action edits, and set changes are possible.