Breakdown of Hulk Movie Special Effects
Chris Townsend and his co-CG sups Gerald Gutschmidt and Michael Dicomo worked closely with veteran visual effects supervisor Dennis Muren and director Ang Lee to achieve just the shade of rage that Lee was looking for in the Hulk. Here, Townsend breaks do
Break it Down: "Hulk"
Chris Townsend and his co-CG sups Gerald Gutschmidt and Michael Dicomo worked closely with veteran visual effects supervisor Dennis Muren and director Ang Lee to achieve just the shade of rage that Lee was looking for in the Hulk. Here, Townsend breaks down the tangled web of work that went into Industrial Light & Magic's 'Banner Lab' sequence -- the not-so-jolly green giant's wild debut.
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"The nature of the sequence changed as we were working on it. Initially, it was going to be a three-month quick and dirty.
"The original intention for the 'Banner Lab' was that it was all about the destruction of the lab. So they did not want to see the Hulk much -- he was supposed to be in shadows most of the time to keep the audience guessing. Gradually, they wanted to see the Hulk more and more, until we had full close-ups on the face with the light shining on him. One of the consequences of that was that it took far longer than three months to do.
"We started out with concept art, and with figuring out how much destruction there would be. I don't think Ang generally likes storyboards. That was one of the interesting things about working with him. It was a comic book that we were basing a lot of the action on, so it was effectively pre-storyboarded.
"The art department in Los Angeles created some sketches, showing that the Hulk smashes through here, he is standing at the lab table here, something happens and the lab table collapses, things like that. The scene is pretty chaotic -- it is difficult to try to plan such a thing. It is a huge sequence in terms of destruction.
"Colin Brady, the animation director, and Dennis Muren, the visual effects supervisor, went down to L.A. to talk to Ang. They had a model of the set on the table in front of Ang, and Colin videotaped him talking about what he wanted. Ang, would say, 'OK, he smashes through this wall and then the camera will be over here and then he's going to walk along here,' etc. It was a great visual aid.
"Then we were given dimensions of the actual set. We re-created the set very simplistically in the computer and used that as a pre-visualization tool. That allowed us to create an animatic with a hulk-like creature.
"Colin and his team of animators then figured out the timing of the set destruction. Once he'd figured out the timing they took it to Ang. There were several iterations of it, and eventually Ang settled on one that he liked.
"The pre-visualization was given to Michael Lantieri and his special effects team. They used it as a guide for timing the physical effects on set. They rigged the smashing up with multiple cameras, because Ang was very interested in using splitscreen effects and thought they would use a lot of it in the lab sequence. They did use quite a bit, but they were planning to use even more.
"They were shooting with six or seven cameras at a time. Michael Lantieri had rigged these incredible cable pulls, explosions, pyro, that kind of stuff. Usually, you rig one or two events to happen in a single pass and then you have a cut away. But Ang wanted five or six events to happen one after the other in a single shot. It was pretty hectic.
"There had been talk of getting an actor to smash through the set and then rotoscoping him out. But Ang didn't want breakaway walls. He wanted real walls with real studs and 2X4s and plaster.
"They set it all up, they shot it, and then they handed us the plates. Our team took matchmove information on set. That was interesting, because you get the information and you take photographs for lighting reference, but throughout the course of the shot, the physical surroundings are changing dramatically. It was quite complicated in terms of the amount of reference that we needed to capture.
"We used the matchmove information in order to re-create the set destruction accurately in the computer, so that the animator could react to the timing and the physical spacing of what was going on, and place the character in that world. The destruction was very simplistically done -- all the animator needed was a reference point, a single plane of geometry. Generally we did not use the matchmoving itself -- we did not render it and use it in the finals. Usually we created the set purely so the character could react to something.
"There were several different ways that we got lighting references. We used lighting diagrams, where you literally have one of the people on location making sketches and taking notes, like, 'the light over there is 8-feet from this one and forty degrees off and it is a 5K white light with a blue gel on it.'
"We also take digital photographs -- we were taking high dynamic range 360-degree fisheye, high-resolution digital image with a Panoscan camera. The Panoscan is basically a lens on a tripod attached to a laptop. It rotates on a motor, taking pictures every three degrees, and then internally stitches the pictures together. We mapped the image onto the geometry, so that we had a three-dimensional representation of exactly what was on set, with approximate textures. The problem is, as I said before, that the set changes over the course of time because it is being destroyed. Therefore, it gets complicated because you have two lighting diagrams, two sets of digital images, etc.
"In a couple of shots there were fluorescent bulbs casting light down through an egg crate grill on the ceiling. So Dennis grabbed a big sheet of white material, put it on floor, and turned them on to get the pattern projected. He filmed a section of the cloth, and had somebody walk through the scene carrying a bust of the Hulk to get a sense of how the light pattern would fall on his shoulders.
"When Ang had picked the three colors that he wanted for the three different sizes of the hulk, the same company that had cast the silicon head cast a slab of each color. The appropriate colored slab would be walked through the set as if it were the Hulk, so that we got a sense of how the light fell on it and how the light changed, what the specularity of it was, etc.
"The nature of the color green is intense. When you put a blue light on it, it looked green. When you put a red light on it, it still looked green -- it didn't change much. That made the character pop, like he was not quite in the scene, so we had to manipulate the colors of everything. Something that Dennis is fond of saying is, 'Trust your eyes.'
"Animating was an iterative process. The animation was based on the animatic that Ang had approved and Michael Lantieri had worked with, so we had a simple blocking of what t
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EarthsMightiestAdmin
8/9/2003
VFXpro