Spotlight | User Focus - August 07
Issue: Volume: 30 Issue: 8 (Aug 2007)

Spotlight | User Focus - August 07

User Focus - CG Modeling
Digital Animals Serve as Extras in Evan Almighty

Rhythm & Hues, calling on its previous experience with creating realistic CG animals, generated a cast of thousands of CG birds, mammals, and other members of the animal kingdom, for the modern-day Noah’s Ark tale, Evan Almighty. Meanwhile, CafeFX created some amusing CG fish for a comedic scene in the movie.

The visual effects facility tapped Massive, an artificial intelligence-driven animation system, to build large establishing shots of hundreds of lifelike computer-generated animals paired two-by-two as described in the biblical story of Noah’s Ark.

Evan Almighty stars Steve Carell in a reprise of his role as newscaster Evan Baxter from the 2003 release Bruce Almighty. In Evan Almighty, Baxter is a newly elected congressman who moves his family from New York to suburban northern Virginia. His life gets thrown into a tailspin when he meets God, played by Morgan Freeman, who instructs him to build an ark. Mayhem ensues when this new venture takes over his life, career, and family.

The movie features a number of shots that set the scale in terms of the quantity of animals that are wrangled to board the ark. These shots were captured with several real animals on set, but not nearly as many as would be required in the final image sequences. Mark Welser, Massive Software supervisor at R&H, oversaw the creation of thousands of creatures, each milling about with behaviors appropriate to its respective species.

“We were able to populate scenes both inside and outside the ark, and fill in terrain with animals that are indistinguishable from hero characters and live animals shot on bluescreen. Massive Software has terrain adaptation and the ability to command navigation so that we could steer the creatures where we needed them to go, and deliver the diversity of actions for the various types of species we needed to create,” explains Welser.

In all, 269 types of unique animals were built into the Massive library set up for this project. Everything ranging from rabbits, badgers, and skunks to elephants and giraffes were animated in Massive. “The tricky part of this assignment was that we needed large numbers of animals to move about randomly, coupled with having to place a number of those animals matched in slightly varied pairs of two—male and female—as told in the biblical story and as specified by the director. So we had to limit some of the randomness in the character placement in order to get animals paired up with others that had similar geometry.”

In Massive, character movements are controlled by “agents” or “brains,” which enable them to interpret and react autonomously to the world around them. R&H used a team of two artists to complete the Massive shots in just over five months. They built 24 agents and applied the agents to groupings of anywhere from two to 53 different types of animals based on similarities in their overall geometry and movement. Some shots featured up to 3800 animals as individually driven Massive agents. These shots ranged from placement of a handful of creatures in the background to shots that were entirely populated by Massive animals, with several of them appearing very close to the camera.

In addition to the nearly 300 different types of animals, R&H had to represent male and female versions of each, which entailed scale offsets, texture variations, and other physical differentiators, such as antlers. The scale offsets, texture variations, antlers, and so forth were also needed to distinguish the animal varieties within the 24 agent groups.  Because of this, the artists also added procedural animation on top of an agent to maximize the variations they could achieve from each of the 24 agent performances.

While the R&H team had five months to complete these shots, it was accommodating test screenings early on. As a result, the team had to put animals into shots quickly—so that even before agents were completed, they had to be prepared to assemble shots. With Massive, the team could easily build a working locomotion agent and then come in at a later date and replace it with a more polished, more sophisticated version of the agent after the fact. 

R&H has integrated into its pipeline, and has used it on a number of projects for everything from building and populating crowds to snakes, soldiers, firing shots, and more.

School of CG Fish

Meanwhile, CafeFX created a scene-stealing school of computer-generated tropical fish for Universal Pictures’ Evan Almighty.

In the film, Evan discovers it isn’t easy being the new Noah, as animals, sensing the impending flood, flock to him in the most unnerving ways and vie for his attention wherever he goes. When Evan visits the office of Congressman Long, played by actor John Goodman, the fish in the legislator’s 100-gallon tank are no exception. Their response to Evan’s animal magnetism is a clever and amusing sight gag.

To create the aquarium sequence, CafeFX modeled and animated 60 CG salt-water tropical fish that exhibit some extremely fishy behavior in Evan’s presence.

CafeFX ordered 10 different varieties of tropical fish through a local shop, so that its digital artists and animators could observe their appearance and behavior, which they then captured with digital cameras and camcorders. “The reference material provided an aid for textures and lighting purposes,” says CafeFX visual effects supervisor Jeff Goldman. “Early in the sequence, we mimicked the actual behavior of the fish in our animation, but as the scene plays out, the fish are a counterpoint to Steve Carell’s comedic timing.”

As Evan and the congressman enter the office, the fish are meandering realistically around their tank. “People can’t even tell they are CG fish,” Goldman notes. “But when they spot Evan, they move toward him in a flash as a fixed unit. He tries to get them to disperse, but much to his dismay, they are almost worshipful of him.”

The prop fish tank was photographed in locked-off shots, filled with water and coral, and wrapped in greenscreen material.  The artists then replaced the greenscreen area with the actors in live-action plates, and put the CG fish into the tank.

“It was pretty straightforward to rig the fish,” says Goldman. “But fish don’t really move the way you think they do. Smaller fish don’t use their tail to propel themselves; they use their lateral fins, and the tail acts as a rudder. Some species of fish don’t move much, and some are constantly moving their fins. What really makes fish look like fish is their movement, and it’s trickier to capture than you might expect.”

CafeFX wrote automation scripts to allow the animators to set up the scenes where the fish hover, swim, meander, and school. The animators tapped all the shaders in Mental Images’ Mental Ray to deal with fish scales and iridescence. “A lot of salt-water fish don’t look like they have scales,” Goldman points out. “It’s almost like they have a velvet texture, and we wanted to simulate that velvety look. Translucency was also critical as a lot of light is transmitted through their fins.”

CafeFX cloned bubbles from the actual tank of water and added bits of CG debris and fish food suspended to the water. “Those minute particles help to ground the fish, otherwise they’d look like they were floating in air,” Goldman notes.

Some of the wide shots with the tank in the background are from the perspective of the fish looking out at Evan from inside the aquarium. “The fish occupy 80 to 90 percent of the screen, and we had to figure out how to deal with a really wide-angle lens, ironically a fish-eye lens, which warps their world. To simulate that warp in 3D requires long render times, so we ramped up our speed greatly by recreating it in 2D using Krokodove plug-ins for Digital Fusion,” Goldman says.

CafeFX employed Autodesk’s Maya for the animation and lighting of the fish, Maya and Pixologic’s ZBrush for modeling, Mental Ray for rendering, and Eyeon’s Digital Fusion for compositing.

“Trying to sell the aquarium joke with all the subtleties of comedic acting, for fish, was a big challenge,” concludes CafeFX visual effects producer David Van Dyke. “But we had a great team with a great sense of humor and they understood what we were trying to achieve.”