The vfx work on Iron Man had to look good for Marvel's first self-financed feature debut, and win over a CG-skeptical director. Courtesy of ILM. All images © 2008 MVLFFLLC. ™ & © 2008 Marvel Ent. All rights reserved.

It's never easy creating effects for a major summer blockbuster, but the work on Iron Man (which opened May 2 through Paramount Pictures) faced the extra burdens of putting a good face on Marvel's first self-financed feature and winning over a director openly skeptical of CG effects.

Created by Stan Lee, Larry Lieber and artist Don Heck in 1963's Tales of Suspense #39, bringing Iron Man to life on the big screen was a big job that Ben Snow, vfx supervisor at lead studio Industrial Light & Magic, says creating a character true to both the comic book and to director Jon Favreau's vision of realism was more complicated that it appeared at first.

Snow wanted to address that issue head on when the company was approached in 2006 to do a test reel for Favreau and overall vfx supervisor John Nelson. "We wanted to make Jon comfortable with the idea of Iron Man as a CG approach," he adds. The resulting one-minute clip impressed Favreau by being realistic and bringing some toughness and real attitude to the CG version of Iron Man and won the ILM the job.

Snow insists that tackling the character for a feature project raised several issues up front. "They had originally talked about doing most of him (Iron Man) in computer graphics and then reality set in, the two realities: The reality of Jon Favreau's desire for this to be as realistic as possible and needing, wanting to have something to pin that to; and also having the reality of not wanting every single shot to be a visual effects shot that featured the Iron Man armor," he says.

Stan Winston Studios created a practical Iron Man outfit for actor Robert Downey Jr. to wear on set. While the armor itself -- based on a design by comics artist Adi Granov -- was a thing of beauty with a stunning sports-car finish that took the vfx crew a lot of work to replicate, the character needed to move easily without being cumbersome.

"It sort of became clear that getting the beautiful profile of a superhero and having a suit that someone could then wear and perform like a superhero in was going to be tricky," Snow says.

Downey often wore only part of the armor, with the rest of it being created via CG using both motion capture processes and animation to make the character look appropriately super heroic. "We have motion capture at our disposal, but we did a lot of work where we needed to have Robert Downey Jr. in part of the suit or some of the suit and then replace the rest of it. That was tricky," says ILM Animation Director Hal Hickel. "Then we had other scenes where the suit was completely on him, and so he's entirely CG but wanted really naturalistic human motion. We did some of that on our motion capture stage here and some of it we just animated, depending on what the needs of the shot were."

Getting the beautiful profile of a superhero and having a suit that could be worn and perform accordingly was tricky. Courtesy of ILM.

The requirements on this movie were more demanding than the innovative on-set motion capture work ILM did for the Pirates of the Caribbean films known as Imocap. On Pirates, ILM captured actor Bill Nighy's performance on set and used the MoCap data as reference, eventually completely replacing the actor with a digital character that could deviate as needed from the MoCap data.

But to make the visible parts of Downey match with the CG parts of Iron Man required extremely accurate tracking. "On this, where you have a shot where Robert is walking around and it's basically his real head and we're adding the suit all over his lower body, it really had to be spot on or his head would slide around and it would look weird," Hickel continues.

In animating Iron Man, Hickel says they tried to give the armor a sense of weight and power without making the armor seem clumsy or slow. "If you built a suit like this, the point of which is to be kind of a battle machine, if it's actually physically restricting or slows the person down then it's kind of really not doing its job," he explains. "It really came down to the performer having the correct attitude, striking the right kind of poses and having the right kind of cool bad-ass sort of thing going on."