Slashdot Mirror
John Knoll on CGI, Tron And 25 Years of Change
StonyandCher writes to tell us John Knoll, visual effects supervisor at Industrial Light and Magic, is using the 25th anniversary of Tron as a platform to look back at the last 25 years of visual effects. "The type of imagery that was possible to create at the time was very clearly computer generated; it wasn't going to fool anybody into thinking it was live action. That was a limitation of the technology that worked very well within the story, that fit right in and made a lot of sense: if you're telling a story about events taking place inside a computer, inside a big virtual environment, what techniques should you use? Parts of the film were done by shooting live action then doing rotoscope and other optical techniques over the top of it, but the stuff that really looked cool and stood out was the stuff that was computer generated."
The grpahics may have changed and look better, but the physics and implementation are still awful. When I see spiderman swing, he just falls too fast and the swing doesnt look natural with the cgi (like, his body doesnt react or stiffen to the G-force).
And when Cgi characters jump off something and land on the ground, most of the time it doesnt look natural. I mean, are they even using earth's gravity acceleration of 9.8 m/s2????
Seriously, look at the scene from the first movie where Peter jumps from building to building. it doesnt look naturally he's falling too fast, and when he lands, the way his body looks when he lands just doesnt look natural. looks as if he just fell 3 feet. his body should have crouched/sunk more.
Syd Mead and the rest of the designers (who's names escape me at the moment) did an incredible job designing to the limitations of CG at the time. The graphics still look great today, and in fact, I think Tron still stands apart from most of today's CG. Almost all of the current CG tries to look like reality, which makes it invisible. With Tron, you knew it was CG and that was cool.
If Tron had only had a good story, good acting, and hadn't opened against ET, this anniversary would have gotten more notice.
Has ruined far more movies than it's improved. When used discretely and where necessary to the story it is fantastic tool. But in too many movies the creators have reveled in their ability to create more and more spectacular stunts and made a movie that showcases CGI talent instead of one with an interesting and well told story. Think the dinosaurs in "Jurassic Park" versus the infamous Jar Jar Binks. One was done very well and effects were used in such a way as to cover the inadequacies of CGI (which are still present today), while the other--well, not so good.
I know, but that's what directors want. I used to do physics simulation for high-end animation. Directors want an end state - they want the character to end up in some specified position. Sometimes one that's unreachable in the physical universe, let alone achievable with human muscle power. That's tough to do with a physics engine.
The way this is usually done in production today is to motion capture lots of motion, splice the bits of motion together, and edit the result manually. The result is some good motion and some bogus motion tied together. It looks bogus, but it's become a cinematic convention.
This really shows up in sports games. When EA runs an EA Football ad during an NFL game, you can tell from way across the room that the motion looks wrong.
Game-like motion has become enough of a cliche to be parodied. The opening scene of Tomb Raider has Angelina Jolie moving like a video game character, tucking and rolling while staying in a single vertical plane, just like the game.
There are many cinematic motion conventions that don't work in the real world. The classic is a car jumping across a gap. In reality, once the front wheels go over the edge, the car starts to rotate forward in pitch at a high rate. When you see a car jump in a movie, there are guides, ramps, extra wheels, and even pneumatic rams involved.
As for "the way his body looks when he lands just doesnt look natural. looks as if he just fell 3 feet. his body should have crouched/sunk more.", that kind of thing is sometimes done with flying rigs and high-speed computer-controlled winches. "Underworld - Evolution" did that. They record and debug the motion in a heavily padded gym, then play it back on the set.
Today, when someone does a tough stunt for real, nobody notices. There's a minor SF film which shows a woman running down the face of a 40-story building with a cable paying out behind her for support. A stuntwoman is really doing that on a real building. And for the bottom 30 feet, the star of the picture is really doing that, twisting to land on her feet and come out shooting. On the screen, it looks no different than similar things done in CG in other movies.