From Variety:

Transformers director Michael Bay returned to the scene of the crime Thursday night at the Cary Grant mixing stage at the Sony lot to revisit the Oscar-nominated achievements in VFX and sound. The place was packed with filmmaking geeks eager to hear and see the behind-the-scenes machinations that go into a formidable FX epic like Transformers.

It was tough for Bay to go back, he admitted after the show, as he's already deep into pre-production on Transformers 2, which is set to start filming on June 2. Bay didn't let the strike stop him. "The strike was a drag," he said. "But I like to write myself. So I wrote 60 pages. I showed the writers something to look at. We'll get back to the torture chamber on Monday." Transformers 2 will deepen the different robot characters as well as the humor, he said. "There's a geriatric robot. If there's an actors strike we'll just stop and start again. We'll make our date." (The movie is scheduled to open June 26, 2009.)

After The Rock, Armageddon, and Pearl Harbor, Bay is tight with the Pentagon and thinks nothing of picking up the phone to get them to reroute a C130 gunship with Seals in it for a few hours. "We pay for the fuel," he says. "The military looks at this as a recruiting effort. The jargon is real. I told them what was happening, and that's what they said. I shot it like a documentary."

Bay, who has a reputation for being tough on crews, endured some good-humored riffing during the show-and-tell, from star Shia LaBeouf as well as his sound designers, editors, and mixers and special FX and ILM VFX artists. Bay was proud that he made Transformers "for a price" he said, in California and New Mexico. "We have the best crews."

For Bay, sound is "50 % of the movie, while the visual effects are a whole other movie unto itself." He shot as much of the film as possible in real locations with live (often dangerous) on-camera stunts and real FX supervised by the legendary John Frazier. In stark contrast to a Star Wars episode which boasts mostly blue screen shots, Transformers had only two days of blue-screen shooting (when the young leads climbed on the shoulders of the robots).

Even the famous shot of the bus that is split apart by a giant robot was a live-action bus blown in two going 60 mph on the freeway with a 30-foot CG robot added six months later. "There's one million details these guys put in the movie," said Frazier, who tried to keep enormous spaces open in the shots for the CG animators to work in.

For LaBeouf and the other actors, "acting without anything there is hard," said Bay. "It's so different when you don't have any environment to react to." LaBeouf described a P.A. holding a long big stick with a green ball on top and shaking it. "They're angry now, shake it faster," he described Bay saying. ILM VFX supervisor Scott Farrar showed the actors a pre-vis--"a cartoon of what's going on in the scene," said Bay, adding, "I always like to put my actors under duress." According to LaBeouf, hanging from a building 20 feet in the air to talk to Megatron or being surrounded by explosions while the cameras wore protective gear was the norm.

On the VFX side, "it's lighting," said Bay. "Everyone looks at light every day and when something looks fake it's not lit well to your brain. We worked on the light, that's why the robots look so real, these things sit next to humans." Bay flew up to ILM in San Francisco frequently, and communicated via satellite link with a pen pointer. He'd never dealt with animation before, which is about performance. "It was painstaking, like Pixar cartoons," he said, "a pain in the ass."

Scott Benza, the animation supervisor, was there to "bring life to the robots," he said. He worked with 30 animators on 16 characters and 47 transformations--each one unique. "It encompasses everything from subtle acting to a full on action scene with brutal robots fighting each other. We gave each artist the freedom to go to town." Optimus Prime has 10108 parts. All the pieces had 4 to 16 layers of information: details, scratches, and metal flake paint with a clear coat finish.

The robots were heavy and massive and athletic and nimble, all at the same time, like Ninja fighters. "They had to have weight and mass and be very cool," said Farrar. The transformations involved "clever people solving puzzles, fitting pieces from one form into another. It would take brute force on each shot until it worked."

The robots also had to act--with complicated facial rigs for the eyes, nose, and mouth-- and each one was different. They rebuilt Bumblebee's eyes three times, making the iris go up and down, until one day in dailies "we saw his soul," said Farrar.

The VFX team took the live-action shots and created CG environments to match them. Said Farrar, "it's about how to make the big guys who are not there look real. You have to go way beyond--the metals look metallic, they look like part of a scene, they fit in with buildings. We are there to put things in the movie that can't be photographed or are difficult or too dangerous to shoot."

Russell Earl did lighting and rendering. "We'd go back and recreate in the computer Scorpinox jumping out of the sand," he said. "We'd copy the scene and use a CG version to match." Adding reflections and highlights and shadow are a big part of making the robots' 20-foot height look real. And making the environment "dirty." Flying debris. Particles. Compositing all these elements is the other huge challenge.

Bay has worked with the same sound crew for 12 years. He affectionately razzed sound mixer Kevin O'Connell as "the biggest loser in Academy history." He's had 19 noms and no wins. This is his 20th go-round.

O'Connell, supervising sound editors Ethan Van Der Ryn and Mike Hopkins, sound rerecording mixer Greg P. Russell and sound mixer Peter Devlin explained how they capture all the distinct sounds on set (dialogue, planes, guns, ricochets, explosions, 9 sets of sounds specific to the robots) and collect it all for the sound mixers to file and manipulate, along with the music. "We take hundreds of sounds," said O'Connell, and try to focus the energy." The goal is to key the audience into what's important in a given scene, and not wind up with "a train wreck of sound."

The sound designers had to come up with characteristic personalities for the different robots, and make the large robot sounds work--partly by throwing the sound to all the speakers in a theater, not just the "dialogue" speaker in the center of the screen.

The sound of Optimus Prime, voiced by Peter Cullen, is about air. Bumble Bee is about buzzing. The sound crew brought a volunteer up to a mike to record sound for Bumble Bee as he groans on the battlefield. The audience listened to the actor live, then heard the sound integrated through the Bumble Bee sound matrix on screen. It magically worked. Big applause. The magic of sound.