It's easy to write off movie special effects as "computer generated," and leave it at that. Take film, run it through a computer, and effects happen! Of course, the actual production of these effects is much more complex than simply feeding video through a magic box.
Motion capture, or "Mocapping," is one of the ways special effects artists make their movie magic. It records body movement and translates it into computer data so it can be used when modeling and animating effects. It's used to produce realistic, fluid animation, especially when animating a humanoid subject, like a robot or a monster.
Typically, motion capture systems use cameras to record movement. The cameras usually use markers, like a reflective object or a glowing light, as points for building a skeletal animation. As each marker moves, the camera picks up that movement and a computer translates that movement into a 3D space. The whole set-up can be very expensive, costing hundreds of thousands of dollars.
Researchers at MIT have developed a new mocap system called Second Skin, which can cost a fraction of the price of a conventional, camera-driven capture system. Instead of a camera picking up light from the subject, Second Skin works in reverse. Projectors flash pulses of infrared light, which tiny light detectors on a subject's clothing pick up and use to determine their location relative in the room.
According to the system's developers, it can be both cheaper and more accurate than conventional mocapping systems. A full system can be put together for around $1,000, and because each sensor has a unique identification and records 500 readings a second, it can be extremely precise.
Currently, Second Skin is only a research project at MIT, and while it's technically impressive, there is no word about it being adopted for use in Hollywood any time soon. Of course, if the price is right, maybe the inexpensive system will see a new generation of independent filmmakers use motion capture and special effects previously only seen in the big studios.
— Will Greenwald
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