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Michael Holzl Tackles 'The Incredible Hulk'

Ellen Wolff catches up with Michael Holzl, a Rhythm & Hues lead animator on The Incredible Hulk.


In fall 2006, Michael Holzl was part of the animation team that successfully landed The Incredible Hulk for R&H. All images ™ & © 2008 Marvel Ent. Courtesy of Rhythm & Hues.

The Incredible Hulk, Marvel Pictures' new version of the comic book classic (now playing from Universal Pictures), has more than a couple of fresh twists. While we've seen versions of the character on both small and large screen (as recently as director Ang Lee's 2003 movie Hulk), this time there was a team of collaborators who brought a different take on the material. Notable among them was director Louis Letterier (best known for The Transporter films) and actor Edward Norton as Dr. Bruce Banner/the Hulk. In this telling of the tale, when Banner mutates into a muscle-bound, raging green Hulk he meets his match in an equally muscle-bound villain called The Abomination -- a mutation of a character played by Tim Roth. Making two world-class actors transform into massive CG mutants was the assignment given to the animators at L.A.-based Rhythm & Hues.

Michael Holzl, a lead animator at Rhythm & Hues, has a nickname that seems tailor-made for this project. The folks at R&H call Holzl -- who's from Australia -- "The Thunder from Down Under." He began working with R&H on 2002's Scooby Doo and developed a reputation for being able to tackle high-action animation. In the fall of 2006, Holzl became part of the original R&H animation team that launched the studio's efforts to land The Incredible Hulk.

"I was on at the start -- with three or four other people -- before we even had the film awarded," Holzl recalls. "We knew we had a good opportunity to get it. The film was awarded in March 2007, so we were working on it for a while before we knew we actually had it. I'm a huge fan of the Hulk and I definitely wanted to get onto this show. So we did tests to get the director excited."

The R&H team used the studio's proprietary animation software Voodoo to previs several key elements of the movie. "That was part of getting us the film," Holzl believes. "A lot of shots had been presented to us as: 'Hulk has to get from here to there… make it look cool!' Later, the director would decide how he wanted to film things based on our previs stuff. He could see the timings and the flow of sequences before he even filmed them. So when he films the action, he wouldn't forget that we'll be putting a nine-foot-tall green character into the scene."

Designing the outsized title character so that he could move realistically was a central challenge for Holzl and his fellow animators. "We looked at Conan The Barbarian and Lou Ferrigno to get a sense of body builders' movements, and we filmed ourselves acting things out, motion-wise. We looked pretty silly doing that, but it came in handy."

Unlike past interpretations of the Hulk, in which the character seemed to resemble something as big as a Macy's Thanksgiving parade balloon, this time the character is more modestly scaled. "Ed Norton had quite an impact on that," says Holzl. "Ed wanted him to be a little more athletic rather than just a mass of muscles. This Hulk is a bit leaner and more agile. In the last Hulk movie, the character would grow depending how angry he got. In this film he doesn't grow so much as get stronger as he gets angrier."

The color of this Hulk was also based on a different green paint chip. "Everyone was well aware of his being neon green in the last film," notes Holzl. "So the color was discussed heavily. They went though different variations -- especially with regard to the color of his blood, and whether it should be red or green. In this film the Hulk does get beaten up enough where he gets cut and bleeds. He did go through different looks, where there were variations on very de-saturated greens where it was almost his normal skin color with a very subtle green in it. That looked pretty realistic, but it didn't give you the feeling that it was The Hulk. It's very hard to make a person look real in green, as well as having the proportions that he does. So they ended up choosing this darker green."

When it came to determining how broad the character's movements would be, Holzl asserts, "It's so easy to go too far. When you have human character doing superhuman things you still have to make him look like he could be alive. In this film, The Hulk could only jump a half-football field at the most!"

Motion capture was an obvious tool for a film like The Incredible Hulk, and the task of capturing the majority of the data was handled by Giant Studios, in collaboration with R&H. Holzl admits to being "an early skeptic" about motion capture, believing that it took away some of the animator's role. "But now I've changed my tune quite a lot. Even when we had a shot that we'd have to keyframe -- for example, a jump that wasn't quite 'superhuman' enough -- we could still see the motion-captured jump 10 different ways, and move around it in 3D. So it's better than video footage. We could see it in every direction and pan around. If there was a MoCap that we couldn't use at all, it still gave us plenty of reference that would help us fill in the blanks. There was no way, as keyframers that we would have gotten that amount of detail to act upon. It definitely enhanced my keyframe animation."

Holzl also notes, "For movements that were very specific to camera or that involved interactions with other elements, it was necessary to keyframe. But we always went through the MoCap data every time a shot was opened. We looked at the actions we had MoCapped to see what was appropriate, or what we could take from it that would help us."

Dynamic simulation was key to enhancing the appearance of the Hulk. The reaction of Hulk's clothing has always been an issue with this character. 

Dynamic simulation also was key to enhancing the appearance of The Hulk and The Abomination, explains Holzl. "Just about every character we do these days goes from animators to technical animators, where they do dynamic things like hair and clothing -- anything that's loose and can be dynamically simulated." The reaction of Bruce Banner's clothing when he emerges as the Hulk has always been an issue with this character, and Holzl says that the production was sensitive to that. "He's not wearing basketball shorts at any time in this film, like he did in the last film. This time, he has three different sets of pants that all rip and look pretty screwed-up once he turns into the Hulk. But they still cling to his body to cover up his 'naughty bits!'"

"There were ripped jeans, so there's lots of trailing cloth hanging off. On every shot there was a pass for all the little extra bits that fly around. There's a section also where he has a ripped shirt that he tears off his body, and that was all dynamic cloth simulation. Simulation was especially important if the clothes had wrinkles in them. But his clothes were pretty tight, so we didn't have to deal with lots of flowing cloth."

Simulating jiggling flesh was particularly significant, and because of this Holzl says, "There was a lot of control given to the animators to handle flex and bounce and bulge. We looked at body builders, and when they don't have their muscles tensed, they do have a lot of give and movement. Then as soon as they flex, they tighten up and jiggle becomes almost non-existent. We used that to our advantage when we were animating the flex. We spent a good amount of time animating that, because it tells the story of how much force he's using and how intense he has to be at the time."

"Body builders are restricted in their movements because their muscles get in the way," notes Holzl. "The most amazing thing on this show was what the riggers did in regards to having the shapes feel right, and the way the skin slid over the muscles in the right places. Some veins would slide over the muscle striations, which were displacement maps."

"The technology that came out of this show on the animation side were things that you didn't see until they were rendered - like the way the muscles slid under the skin. We'll apply that skin-slide stuff to every show from now on. This does have an impact on the render times, though."

The color of this Hulk was based on a different green paint chip than in previous incarnations. Instead of the neon green from the last film, a darker shade of green was chosen.

While The Incredible Hulk doesn't focus on many transformation shots, Holzl remarks, "The Hulk does have some moments where he's changing. The riggers were the main force in getting that to work. From the very beginning the director didn't seem too concerned to make the Hulk look a lot like Ed Norton. Just a little scar that he had was transitioned over. People were actually more concerned about his hair, to be sure and get the shape right."

The Hulk's nemesis, the Abomination, was the product of the transformation of Tim Roth's character, and Holzl notes, "He has a tattoo on his arm that transformed when he turned into the Abomination. But the director didn't seem too concerned that you'd look at them and not know who they were. The Abomination has never been seen as a character off the comic book pages, so we had quite a lot of freedom with him. The Abomination character actually has control of his rage. He's angry when he's the Abomination, but he still has enough mindset to make decisions. So he's much more cunning with his movements, and very specific. He'd jump over things and avoid obstacles -- he's much more intelligent about his movements, whereas the Hulk was in such a rage that he'd just be bashing through the city."

The Abomination's creepy, protruding spine was difficult to work with, says Holzl, but he observes, "People haven't seen something like this before, so they forgive a little more how it should move. With the Hulk, because he does follow the structure of a human bodybuilder much more, it's easier to pick out things that you may think don't quite look right. So for the Abomination, in the end, it was a bit easier to get to a realistic result."

The Abomination's creepy, protruding spine was difficult to work with, says Holzl, but the animators had freedom since the audience hasn't seen something like this before and doesn't know how it should move.

When it came time to integrate these characters into plate photography, R&H software enabled the animators to re-time the plate when necessary. As Holzl explains, "We had a curve that represented the speed changes and we could slow it down or speed it up. That information would get it sent off the people who comped in the 2D background -- they filled in frames where it was too slow and cut out frames where it was too fast. Also, the film was shot in 35 millimeter so we had a lot of play on some of the shots. We could pan over the frame ourselves as animators. We had quite a few more pixels to work with -- to make it feel a bit more like the camera was following the animated action. We didn't have to do too many cheats. Re-timing the plate and panning over it were both at our disposal. This gives an animator a lot more creative authority. For one of the biggest shots that was fully 3D, we had complete control of the camera the whole time. On this show, animators had a little more control over the shot because of those re-timing and the panning abilities."

What sells the integration of CG characters in a live-action setting is how believably they interact with other elements in the scene, and Holzl says, "The Hulk definitely touches and interacts with a lot of things -- especially the ground. When he's running he leaves quite an impact. This was definitely a huge challenge because The Hulk was so destructive. We had a lot of 3D-CG things in there. The Abomination throws a hot dog stand down the street that was all CG. It flies past camera and comes apart and hot dogs go flying. And there are lots of CG cars that he hits."

Of course, all of this builds up to a climactic scene in which Hulk and Abomination do battle. One of Holzl's main responsibilities was serving as lead animator on this sequence. "It's a showdown, where they're looking at each other from opposite ends of the street, and then they run toward each other." Holzl notes, "The Hulk is actually changing to help humanity. That gave us a chance to put him in a hero position, rather than have him be the one who was always tearing things up." But the challenge of making the two CG behemoths do battle prompted Holzl and his fellow animators to do some homework. "We looked at a lot of mixed martial arts footage for reference because they do get very physical. These two characters don't have weapons -- all they can do is throw stuff at each other when they're not in close contact. I did quite a few shots where the Hulk has the Abomination right up against a wall with his arm against his neck, doing uppercuts and head butts.

"The biggest challenge of having both characters in a scene was that we didn't want the Hulk to look too small compared to the Abomination. The Hulk is nine-feet tall compared to the Abomination at 11-feet. I did have a scene early on where the Abomination's hand is grabbing onto Hulk's face. But his hand could wrap around the Hulk's face so easily it would look like he could squeeze it like a grape.

"There were interesting challenges with regards to that. If Hulk was going to come up behind the Abomination, he'd have to be in a somewhat crouched position, but we didn't want it to look like he got into that position so the Hulk could get him! Scale was definitely a challenge," Holzl admits.

"On rare occasions, we did do some cheats here and there. That's usually a no-no because problems like hair dynamics can come into play. I did have a couple of shots where I did scale him slightly. But we didn't keyframe the scale throughout a shot. We'd just have them at a certain size -- usually if they were next to a car or person. When they were with each other, they'd be at the correct scale." Holzl laughs when he considers all the elements that Rhythm & Hues had to juggle to tackle The Incredible Hulk. But he wouldn't have missed the chance. "In my heart," he says, "I'm a creature guy!"

Ellen Wolff is a southern California-based writer whose articles have appeared in other publications, including Daily Variety, Millimeter, Animation Magazine, Video Systems and the website Her areas of special interest are computer animation and digital visual effects.