Nerd Guru

Because technical people need good soft skills to get ahead.

Monday, October 01, 2007

My nerd crush on John Dykstra

If you were to watch 2001: A Space Oydessy (aka 2001, which came out in 1968) and Star Wars: A New Hope (aka ANH, which came out in 1977), you would notice a pretty significant difference in the visual effects despite both films winning the Oscar in that category (albeit 9 years apart). 2001 utilized cutting edge blue screen techniques that layered a variety of futuristic scenery on top of each other, but mostly with camera positions that didn't move. As anybody knows who has watched the Death Start trench scene of ANH can tell you that the shots not only move, but move quickly and achieve a high level of excitement in the process.

So, what's the main difference in the visual effects between the two films? John Dkystra.

Early in the production of ANH, George Lucas knew he was going to need a technological breakthrough in order to make the kind of movie he wanted to make. To accomplish this, he established his own special effects company called Industrial Light and Magic. One of the original employees of ILM was John Dykstra.

As chronicled in Empire Building, Dykstra and his team spent the months that Lucas was location filming in Tunisia back in California working on what would become the Dykstraflex motion control camera. Although Lucas was flabbergasted that no shots had been completed when he returned from Africa, the system that Dykstra's group created would change movie making for decades until the arrival of computer generated imagery.

To fully appreciate Dykstra's achievement, you have to understand a bit about how movies used to be assembled. While I'm sure some film student will poke holes in my explanation, my poor man's version follows here.

Most visual effects in movies are assembled from different shots and combined using a process called compositing. Pre-computers, compositing had to be done using special machines that would run different film reels together and record the result. Since film is inherently a transparent medium, this takes some careful planning.

Suppose you want a shot of a space ship moving across the screen with a star field in the background. Such a shot would be comprised of at least three separate pieces of film, or "plates". The background plate would be the star field. The foreground plate would be the space ship, typically a photographed model since space ships don't exist in real life the way they do in movies.

Intuition tells you that you simply combine the foreground with the background and you have your shot, but it doesn't exactly work that way. Think about what would happen if you had a single light source projecting the background and foreground plates together. What you'd get is the two images overlapping each other and the stars would appear to be on top of the space ship.

In order to remove the stars from the space ship, you need a third plate which blacks out the stars in the exact shape of the spaceship. There are a variety of techniques that can create that third plate, but before Dykstra's work, it was extremely difficult to do unless the camera position was fixed. If you could move the camera, you could make the model space ship look like it was flying in a much more realistic way. This was Lucas' requirement and Dykstra met it.

How? By taking an old camera and attaching electric motors to each basic function (pans, tilts, zooms, etc.) along with a series of integrated circuits that could remember the motions. The camera could be programmed to make a set of movements once and then exactly duplicate that set of movements as many times as needed. That meant Dykstra could program the camera, shoot the foreground shot of the model, change the lighting conditions, and then shoot the exact same movements for the blacking out plate.

The resulting composite was much more fluid and realistic than had been possible before. Although the system is largely obsoleted by computer generated images used in today's movies, it was a huge leap in capability at the time. Dykstra left ILM before work on The Empire Strikes Back began, but he continued to work on special effects having most recently been the Special Effects Supervisor for Spiderman 2.

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posted by Pete Johnson @ 10:33 AM   0 comments links to this post

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