When Benjamin appears in his 80s, 70s, and mid-60s in The Curious Case of Benjamin Button, he is completely CG from the neck up. Courtesy of Digital Domain. All images © 2008 Paramount Pictures and Warner Bros. Ent.

The long and winding 40-year journey to bring The Curious Case of Benjamin Button to the screeen ultimately became a vfx struggle as much as a storytelling one. How fitting for this reverse aging saga about maturity and mortality adapted from the F. Scott Fitzgerald novella and starring Brad Pitt.

Not surprisingly, director David Fincher (who's been attached to Button on and off for six years) turned to Digital Domain, with whom he's worked for more than a decade on commercials and smaller films, to solve the crucial performance capture challenge. It was a process that began with research in 2002 but didn't get solved until much later.

For approximately the first 52 minutes of the movie, when Benjamin appears in his 80s, 70s and mid-60s, he's not Pitt in makeup. He is completely CG from the neck up, created by Digital Domain. The first shot is where Button sits at the table and drops the fork. The last is where he turns his head on the tugboat in the snow.

"I've been working with David since 2002 on various commercials," recalls Eric Barba, Digital Domain's visual effects supervisor on Button. "He talked to me about the various challenges of making this movie. The thing that I love about David is that he doesn't have comfort that it can be done. He's more about: 'I can put the pieces together in my head of what you've shown me and what you've done. This can be done with the right budget, time and schedule -- you guys can figure this out.' He is just fearless with connecting the dots. In working with him, he's constantly pushing the envelope, even on commercials. We knew there were amazing challenges that we had to figure out."

Indeed, in 2004, Fincher got serious about getting the project greenlit by Paramount and Warner Bros. He put together an art department to start production design and scout locations, switching from Baltimore to New Orleans. "Ultimately, he asked us to do a test," Barba continues. "We had a five-week post schedule with a team of artisans to break the process down."

In the test, which did not involve Pitt, they tracked a head onto a body in a seamless way and rendered skin and hair that looked believable and compelling. There was no speaking and the range of motion was limited, but the test built confidence at Digital Domain after receiving a positive response from the studios and producers Kathleen Kennedy and Frank Marshall.

According to Ed Ulbrich, one of Digital Domain's VPs, who exec-produced the vfx, the test achieved its purpose "but also scared the hell out of us because we had to figure out the missing pieces and try to find other technology and tools that had been used for other purposes and repurpose them for this, and figure out what code needed to be developed in the middle to make it all work."

Even after a successful test in which a head was tracked onto a body seamlessly, Digital Domain still had to figure out the missing pieces to make the effect work. Courtesy of Digital Domain.

They also needed to work out an all-digital workflow, so basically Digital Domain used commercials as funded R&D. Along the way, they additionally figured out how to deal with cloth and fabric as well as ideas about how to deal with the human face.

And, as Fincher worked on Zodiac, Digital Domain made the controversial Orville Redenbacher spot, which, though turning out more creepy than uncanny, provided another R&D opportunity. "David may have had confidence from the beginning but we didn't," admits Character Supervisor Steve Preeg. "Having worked in rigging in this industry for quite some time, it's definitely a scary thing to even think about [achieving this feat]. In fact, everyone we tried to hire to work on it, felt the same way. It was actually quite hard to staff up for the show, which was surprising. But during the Orville Redenbacher [experience], we had a certain number of constraints put on us to test certain aspects, most of which didn't work out, but there were some little [kernels] of optimism."

Barba adds, "With the bleeding edge of technology, you certainly get cut and hurt and that was the case with Redenbacher. Commercial budgets and schedules are tiny compared to features and we put together a fantastic team, but schedule and the technology maybe let us down a tiny bit, and maybe some of our own plans. But if we hadn't done that, I don't think we would've gotten the head start on Benjamin Button. For me, as much as I hate failing, it was absolutely necessary to go through this process. It left a scar but it didn't kill us."

Before they actually started on Button, there was another head replacement test for a feature that didn't get greenlit, which allowed more experimentation. "I was by myself in a dark corner but started thinking that maybe we could get there," recalls Preeg. "Finally, we did some capture sessions with Brad and quick [wire frame] animation of Brad and showed it to David, who got excited at that point.

Then came pre-production. The chief hurdle was still animation: How do they make this believable? And tracking: How do they make this head sit in this world? And lighting and compositing: How do they create a system that could realistically drop these heads into this amazing cinematography?