Processing: Creative Coding and Computational Art

PROCESSING: CREATIVE CODING AND COMPUTATIONAL ART
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Figure 4-4. Blind spot example
Some persistence of vision begins at a fairly low frame rate. Flip books are a good example
of this; it doesn’t take too much speed to get some sense of animated motion. Film has
a frame rate of 24 fps (frames per second). NTSC video is about 30 fps (actually, 29.97,
with two interlaced fields each refreshing at that rate to avoid flicker). Web animation/
video ranges from 12 fps to over 30 fps, depending upon connection speed, file size, the
processor, and so on. At 12 fps, you notice a flicker in animation, but 12 fps was about as
good as it got in the early days of the Web. Faster modems and the proliferation of broadband
now allow web animation to approach comparable frame rates to film and video. In
addition, web streaming technologies and improved codecs (compression algorithms)
were developed to allow motion data to begin playing in the browser while content was
still downloading, increasing image quality and eliminating long download delays. Outside
of the Web, it is also possible to shoot film or generate computer animation with much
higher frame rates than 30 fps, allowing you to do things like slow down the film and still
get smooth motion. This is precisely what artist Bill Viola did in his video art piece The
Quintet of Remembrance, installed at The Metropolitan Museum of Art in New York. Viola
shot 60 seconds of footage for the piece with very high-speed film. He then slowed the
piece down to over 16 minutes. In the piece, five actors, standing in a tight grouping, are
each expressing intense emotion, referencing three important historical paintings. The
silent piece unfolds incredibly slowly, yet with absolute clarity and free of any flicker,
creating a very unique and memorable viewing experience. The high-speed film obviously
captured enough frames to allow it to be played back 16 times slower, while still maintaining
at least a 24 fps frame rate. Here’s a link to the piece: www.metmuseum.org/toah/
ho/11/na/ho_2001.395a-I.htm.
Popular computer animation software applications such as Flash, After Effects, and
LightWave borrow concepts from traditional animation, film, and video. These applications
are timeline-based, in which users specify keyframes—the beginning and ending points of
animated sequences—and the software generates the frames between the keyframes, or
the in-betweens, in animation speak. In the golden days of traditional cell animation, the
master animator created the keyframes, while the apprentice animators (the human inbetweeners)
handled the rest of the frames. In digital animation, it doesn’t matter if the
animated object or effect is an imaging filter, 3D character, ball, light, camera, texture
map, or particle generator; every object has a set of properties (x and y coordinates, width,
height, etc.) that can be changed over time by setting keyframes on the timeline. Some of
the higher-end animation tools even have their own proprietary programming languages
built into the application, allowing code to control these timeline envelopes as well.
Animation software applications can be divided up by their core functionality. For example,
the three popular animation packages I referenced—Flash, After Effects, and LightWave—
are each used for different primary purposes. Flash is used for 2D web-based animation
and web design/development; After Effects is used for motion design, compositing, and
imaging effects for film and video; and LightWave is used for 3D modeling and animation.