When the visual effects and animation wizards at Industrial Light & Magic started working on Paramount Pictures film Iron Man, their biggest challenge was creating a suit for the title character that was part CGI (computer-generated imagery) and part real costumery.
If you're not familiar with Iron Man, it's the story of Tony Stark, a genius billionaire industrialist who's also a bit of a jerk and who designs and sells weapons. In the film's opening sequences, Stark is demonstrating one of his weapons in some unspecified country near Afghanistan when he is captured by terrorists who demand that he craft a weapon for them. In the scuffle that ensues, he ends up wounded, with shrapnel lodged near his heart.
To make a long story short, Stark ends up making an iron full-body suit that protects him and his wounded heart, and along the way, he ends up going through a personality transplant and becoming a superhero instead of a force for evil.
But it all comes back to Iron Man's suit--a technical marvel that allows him to fly, shoot missiles, be impervious to many conventional forms of attack, and more. To watch video from the film, you see that the suit has no end of little flaps and compartments that all seem to operate independently and which are all essential to giving the Iron Man character his fully teched-out superhero flavor.
The problem was, according to ILM visual effects supervisor Ben Snow, that the traditional options for creating a suit like Iron Man's--either making it fully CGI or making it a fully real-life, physical, or "practical," suit--weren't going to work for this film.
"The suit has to do a lot more than just a suit of armor can do," Snow said when I visited ILM recently.
To begin with, the producers commissioned a practical suit for Iron Man, something that lead actor Robert Downey Jr. would have to wear on the set. But as the production advanced, the visual effects team became more confident with how they could influence how the suit was integrated into the film--and Snow and his team began to make more and more suggestions of how to blend CGI with the practical suit.
"One of the fun things for ILM," Snow said, "was that we got to contribute to the ideas of what makes the suit tick."
That meant, Snow added, that the film's director, Jon Favreau, encouraged him and his team to get creative in the ways they planned to blend CGI with the practical suit Downey wore on the set.
One issue that made it difficult to rely too much on the practical suit was that it was heavy and therefore a burden for Downey to wear. The weight of the real suit made it hard for the actor to do the full range of motions that the script called for.
So as the team figured out ways to do more and more elements of the suit with computer graphics, Downey and others who wear iron suits in the film began to discover that they didn't always have to be wearing so much weight.
"When the actors and the stunts realized they could pull parts off (of) the suit," Snow said, "they were trying to take parts off all the time."
The solution? Snow and his team began to offer joking bribes to the actors not to remove the pieces.
"We'd offer them half the cost of doing the scene in CG," he joked, "and we'd pocket the other half."
Still, the job required a great deal of CG--but graphics work that had to be painstakingly accurate.
"The hardest part about this," Snow said, "(is) sometimes the real guy is inside (the suit, so) you have to make sure it moves the same way as the real guy."
Favreau wanted realism in the CG work, Snow added, and didn't want the CG work to make Iron Man's motions look too "martial arts."
But after some time, it seemed like the visual effects and animation specialists were getting really good at what they were doing. So good, in fact, that sometimes when the dailies came in, the lines between where the real suit ended and the CGI began wasn't clear.
"At some point," Snow said, "Jon Favreau started asking questions about the suit (thinking it was real). At this point, we realized that they'd stopped being able to tell what was CG and what was real and that was really great. Jon Favreau rang me up and said, 'Look, I've got a problem with this shot. It's very CG looking. Can you do something about it?' I said, 'Jon, that's actually a practical suit. It's not CG.'"
That was certainly an important moment for everyone because, Snow said, Favreau wanted things in the film to look as realistic as possible.
For example, in a widely-seen sequence in the film in which Iron Man is flying through the air, pursued by fighter jets, most of the action in the foreground is CG. But in order to get the clouds to come across as authentic, Favreau used real footage of clouds taken from an airplane above them. And then Snow and his team blended the two elements.
While Snow and his team were working on the visual effects of Iron Man's suit, ILM animation supervisor Hal Hickel--whofor visual effects for his work on Pirates of the Caribbean: Dead Man's Chest--was dealing with things like figuring out how to make Iron Man's flying motions feel right to the audience.
"It ended up being really challenging, the flying," Hickel said, "figuring out how he should fly. Iron Man takes off slowly like a heavy object, and then lands very fast because he weighs a lot."
Another big challenge was working out the size scale differences in fighting sequences between Iron Man--a normal human-size--and his enemy, Iron Monger, who is meant to be 15 feet tall.
But the scale difference was too great to do with live action, Hickel said.
"We backed the camera off and reconstructed the set digitally," he said.
Another big challenge for Hickel and his team was "trying to remind the audience that there's a man in (the suit) and that he's in jeopardy."
That meant trying to figure out ways to show Downey's face, even when he is in the suit.
"We tried to have little performance nuances that signaled to you that he's not a robot," Hickel said, adding that one way of achieving that was to film Downey in a motion capture suit and incorporating that footage into the animation process.
"It was a great help," Hickel said, "and he was excited that he didn't have to wear the full practical armored suit."