James Cameron’s Avatar broke box-office records and is now doing the same with DVD and Blu-Ray™ sales. This is quite a feat, especially when considering that more than seventy percent of what is seen on screen was generated through the Motion Capture (MoCap) technology. In other words, most of the characters we see on the screen are not real people, but rather the ultimate in lifelike animations created with this groundbreaking technology. We have all seen the behind-the-scenes, making-of-the-film footage; but how many of us truly understand the workings of this innovative film technique?
The most basic concept behind this technology is that it creates a three-dimensional (3-D) representation of the figure it “captures.” This is achieved by placing upon the subject (actor, dancer, stunt person) very small (from eight to thirteen millimeters) foam balls, called markers, covered in a thin layer of reflective mesh. The performer wears a tight-fitting black suit and cap to which the markers are attached by Velcro patches. When multiple performers are being captured, each performer’s Velcro patches are a unique color, indigenous to each performer. In addition, there is a unique configuration of marker placement to distinguish each performer.
The subject is then placed in the work area, called the Volume, which is a large rectangular region entirely surrounded by special “cameras” which do not photograph images; but rather the 3-D representation it creates from the markers’ configuration. In essence, the Volume is like a fish tank, it is a container; but instead of containing water, it contains space. The Volume is its own three-dimensional “world” in rectangular form.
A medium-sized Volume, 120 feet by 40 feet, is bordered by 150-200 of these cameras, like the Vicon™ T60, one of the most popular brands of these camera types. The camera’s center holds the “image”-capturing element and is encircled by concentric bands of red, strobe-emitters. This strobe light cycles too quickly for the human eye to see, and creates the continuous reflection off the markers, thus pinpointing the markers’ locations in the Volume on a constant, updating basis. The camera could better be considered a sensor or receptor, as it receives the reflection from the marker and that determines where precisely in the Volume it exists per nanosecond.
The information regarding the markers’ location, shape and configuration is called data as it is interpreted in numerical values and language through the special computer program, which allows the “creative people” to manipulate the information. Visually, the computer operator capturing the input in real-time sees different-colored stick figures in herky-jerky motion; it is only later, in the editing and animation processes that the movements are represented naturalistically and fluidly.
A subset of MoCap is called Performance Capture (PerfCap). MoCap provides a grosser picture of the performer, that is, markers are placed at the major joint locations of the body – knees and elbows, for example, and so provide a broad sketch of the figure being captured – skeletal imprint. Performance Capture is much more precise and subtle. The difference between MoCap and PerfCap can be likened to the difference of painting style between van Gogh and Rembrandt. While van Gogh painted in broad, suggestive strokes, Rembrandt was the master of fine detail – his portraits looked almost like photographs, they were so vivid and life-like.
PerfCap captures not only the performer’s physicality, but also the subtleties of his facial performance. Small, white reflective markers about the size of a pencil eraser are placed at strategic points on the performer’s face. They are arranged to capture facial movements when muscles are contracted, for instance, in a smile or a frown. The more markers placed, the more specific the captured performance. The average is fifty facial markers. To achieve a cleaner performance from the body movements, smaller body markers are used as well. In MoCap, twelve- and thirteen-millimeter markers are used; for PerfCap, it is the eight-millimeter size that is employed. The smaller-sized markers force the program to narrow its analysis of where in space they, and consequently the performer, are. It provides a more detailed performance.
This is the nuts and bolts of the Motion Capture and Performance Capture processes; the performer(s) carry out physical actions and sometimes dialogue, and this is all captured through special cameras and interpreted by the proprietary computer program. This technology is used, not only for the making of feature films and television; but more so in the production of videogames. An exponentially expanding market, most videogames are produced using either of these technologies. The performers might be pirates carrying out an elaborate swordfight as in Pirates of the Caribbean: Armada of the Damned being released in 2011 (Propaganda Games™). The performer can be an animal as well. For Red Dead Redemption (Rockstar Games™), a real horse was “markered up” to create more realistic movements for the equines in the game as well. An interesting side note: especially when stunts are involved and there is physical contact, markers can be dislodged; this is very serious as it throws off the performer’s calibration. If this happens, you will hear someone on the set yell, “Marker down!” Someone then rushes in to replace the missing marker.
How the visual characters are created is another story. That is carried out by the animators who apply a character’s conceptual design to the data that was captured. The MoCap process is the inception of the whole process. This is where all these amazing effects begin.
Now is this technology ultimately a boon or a detriment to the Film Industry? Much can be said regarding the decline in quality storylines in the past few years in deference to greater visual effects. The ratio of action and special effects-driven films compared to simple screenplays focusing upon interesting characters and plots is depressingly overbalanced. The remaining pedestrian scripts are primarily romantic fluff and sophomoric broad comedies. As British journalist and novelist, Will Self opines, “Of course good -- even great -- movies are still being made, it would be absurd to deny it, but it's this level of cultural primacy that has gone for ever” (2010, para. 10). Let us hope that the novelty of these innovations dissipates, and good filmmaking returns to “a theater near you” soon!
References
Self, W. (2010, August 28). Cut! That’s all, folks; Film is dead. The Times (London). P. 38. Retrieved September 1, 2010, from http://proquest.umi.com/pqdweb?index=4&-did=2123303081&SrchMode=1&sid=1&Fmt=3&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1283631163&clientId=74379
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