The kinetic arts

My vote for the most beautiful scene put on film in 2005 would have to be the finale of Peter Jackson's King Kong — the sunrise battle atop the Empire State Building. What struck me most about this scene was the beautiful and very realistic motion of those lightweight, canvas-winged biplanes, the way they floated so convincingly on the air. CGI has never captured airplanes in flight so faithfully.

This got me thinking about CGI and science fiction, and how/why spacecraft are always depicted as moving as though they were aircraft.

[ the geeking starts here, in earnest ]

It's a balance of terrestrial forces (thrust vs. air resistance, lift vs. gravity) that shape the familiar, predictable motions of aircraft — they turn by banking, accelerate in a dive, etc. Special effects artists have long emulated these motions when depicting ships in space (the ships in the Star Wars movies “dogfight” just like planes in WWII; they even do strafing runs, and plummet into spinning dives when hit). As a result, these effects look convincing — even if they're inaccurate for ships in a weightless vacuum — because the apparent motion is familiar and thus believable.

Pre-CGI “realism” was also greatly helped by the necessity of using models. To create apparent motion, you had to physically move the model (or the camera). There is a gut-level believability to even the crudest of these effects, because even if the thing looks fake, it's still clearly a physical thing, bound by physical laws of motion. With models, considerations like perspective, line-of-sight, depth of focus, the effects of light, and the relative motion of two objects are all pretty much WYSIWYG.

This is why much of the CGI we've seen over the last 15 years is so unconvincing — it may look real, but it often doesn't move real. The clearest examples of this are the Special Editions of the original Star Wars trilogy released in 1997. The new, “improved” effects allowed the starships more freedom of movement — too much freedom. They danced around in absurd and unnatural paths that seemed two-dimensional and cartoony, and the perspective was all out of whack. Despite the image quality and clarity, there's an instinctive reaction to bad kinetics that robs special effects of their realism.

Just as Peter Jackson perfected the look and feel of CGI aircraft for King Kong, the effects artists for the new Battlestar Galactica are finally using CGI to liberate their spaceships from the “traditional” effects of gravity and atmosphere, allowing them to move freely in space as they should. The ships are propelled not by continuous forward thrust, but by a single burst of power to build velocity, after which they are carried forward simply by momentum. To maneuver, they use small thrusters to adjust pitch, yaw, and roll, allowing the ships to fly backwards or sideways, or to turn completely around in place to face a pursuer.

(If you played a lot of “Asteroids” in the 80s, you get the idea.)

The effect is quiet and graceful, and — once you adjust to the physics of it — perfectly natural. Traditional chases and dogfights are thrown out in favor of nonlinear battles that have the kinetic dynamics of, say, a massive, three-dimensional snowball fight.

If there's television in the afterlife, I hope Isaac Newton is watching Battlestar Galactica. Never have his three laws of motion been so faithfully depicted, and by a genre that tends to prefer the three laws of a wholly different Isaac.