Martin Scorsese tackles 3-D for the first time. All images © 2011 GK Films. All Rights Reserved.

Hugo is a natural for 3-D; in fact, it's one of the few films that cry out for 3-D, with its storybook spatial opportunities: the magnificent Paris train station of 1931 and the myriad of clocks within it, and the recreation of Georges Méliès wondrous glass studio and magical silent films.

Once Martin Scorsese decided to embrace 3-D, there was no turning back. It had to be done right. The idea was to be on the set with the characters. You're with Hugo in the train station; up in the clocks; in the toy store; or with Méliès in the glass studio. It's about the thrill of discovery.

This not only meant shooting in 3-D (with the Alexa and the Fusion 3D stereo rig from Cameron|Pace), but also having the ability to view it live in 3-D to make the proper creative choices and adjustments to the convergence. In fact, if Scorsese couldn't view it in 3-D, then he had no use for it. The flat version was even an afterthought, so take note: Hugo must be seen in 3-D to be fully appreciated.

Indeed, this is 3-D that went beyond the limits of the stereo rig to make the camera separation conform to the human eye. That's why it contains so much more depth than any other 3-D movie you've seen. It's certainly made true believers of Scorsese, who recently said that it's a natural part of the viewing experience, and production VFX supervisor/2nd unit director Rob Legato, who says it's changed the grammar of film.

The clocks of the station play a big role.

But more than that, Hugo has changed the way VFX and 3-D work together because, even though the movie was shot in 3-D, it required CG enhancement (more than 800 shots with unique VFX needs) and sweetening to achieve its impact, which is significant. Truth be told, there never was a locked edit until the final day of delivery. They were accepting new VFX shots 48 hours before the deadline to film out the film.

Take the opening fly-through the Paris train station, which looks like a single shot. It's the most complicated sequence and took more than a year to achieve, thanks to the combined efforts of the crew and Pixomondo, which worked on the VFX in nine of its facilities worldwide.

"It took Pixomondo 1,000 computers to process all the material for a giant wide shot of the train station that goes into a tight close-up of Hugo watching through a clock," explains Legato. "It took more than a year to complete. They worked in Stuttgart, Frankfurt, Berlin, London, Toronto, Los Angeles, Burbank, Beijing, and Shanghai. It was the first shot I designed for the movie because we had to figure out the live-action concourse part and what vehicle could get up to speed fast enough to make the whole shot play in a comfortable time.

"I prevised the opening which was created with a virtual camera of sorts. It's a scaled down version of the Avatar setup using encoded mini crane, and fluid head instead of motion capture, but the concept is the same, as is the software [Motion Builder]. The full size virtual camera was an encoded Louma crane on the live set and real time composite of the CG background and people.

"Where the live action ends and the CG starts is very seamless. The only thing built was the main concourse, a smaller under hang and the front door. It was all greenscreen with CG extension throughout, live action in the middle with CG extension and CG at the end."