After his recent success with MONSTER HOUSE, director Gil Kenan put his talents to work on this adaptation of the Jeanne DuPrau novel, CITY OF EMBER. Together with Production Designer Martin Laing, the team set out to create a world where light is the lifeblood and a failing generator is the faintly beating heart of a dying race.

Luma was the lead vfx provider on the film, contributing more than 100 visual effects shots that run the gamut from full CG sets of amazing complexity to raging rapids and water simulations as well as a 9-foot mole that terrorizes the film's young cast.

Luma has grown significantly since its first steps into vfx with UNDERWORLD and THE HUMAN STAIN and has built a robust and powerful pipeline capable of handling the most complex and challenging shots in the film. "Nothing in this package is 'assembly line,'" noted Luma Pictures Visual Effects Supervisor Vincent Cirelli. "Every shot is customized. Every department was fully engaged in the project and they had to communicate at a very high level to make all the pieces fit."

CITY OF EMBER is set in a subterranean world that appears to be coming apart at the seams, and the tale turns on the effort of two kids to save the city. At the heart of the city is an enormous water powered generator that has been in operation for 200 years and has fallen into disrepair, its gears binding and oil spewing from its leaking joints.

For the production, a small section base of the generator room was built practically, but the bulk of it, stretching some five stories into the air and extending for hundreds of feet along the main waterway, is CG. "Often you can get away with building only what you need for the camera, but in this case the cameras went everywhere," Cirelli noted. "In addition, there were a number of completely CG shots in the machine room, where the moving pipes and pistons of the generator are located, with the only practical element being a ladder for the actors to climb."

The concept design was the primarily the work of production designer Martin Laing, but it fell to Luma to flesh out the finer details of the behemoth, a task it undertook with characteristic zeal. "We have a fantastic lead environment artist in house, Chris Sage, who came to Luma from an architectural background, and that was essential to creating something like this," Cirelli said. "This isn't about creating images, it's more like creating an actual functioning machine. Every detail of the plant has a purpose and a function."

"All of the CG objects have a history," explained Luma VFX Supervising Producer Steven Swanson. "We imagined what would happen to it through nearly 200 years of oil, grease and corrosion. And it's not just part of the design... it's also evident in the animation. The gears wobble, the cables are no longer locked down. Steam is pushing out and oil is oozing."

Equally impressive in scope are Luma's water simulations. The film's heroes make their escape from the city in a crude canoe that barrels down a tunnel on the back of a raging torrent of water. The water-every drop of it-is CG. Water is something that sets Luma apart from other studios, according to Cirelli. "Over the course of several projects that required CG water, we have refined a skill set that allows us to handle a large number of shots where water is one of the lead characters"

Cirelli noted that "most CG water effects fall into one of two categories: large bodies of water that convey volume and general motion, but obscure smaller details and small water systems with details down to the droplets of water and spray coming from turbulence. CITY OF EMBER required both."

Simulating a river full of rapids requires a level of detail that demands intense computing power and planning. "In order to create such imagery, we needed to create a processes and proprietary tools that would allow us to sculpt the simulation. Because simulations are based on physics, they generally do not cooperate when trying to attain very specific art direction."