|CGSociety :: Production Focus|
16 March 2007, by Barbara Robertson
Following its US release, 'The Host' has made quite a stir among cinema goers. We repost this original CG feature from last year which delved into the production of this schlock-horror flick with work by The Orphanage.
Nothing is quite normal in ‘The Host’, a quirky horror film from South Korean director Bong Joon-ho. The mutant monster that arises from the Han River in Seoul to terrorize people in a riverside park is, of course, the most abnormal and sometimes exceedingly gross element in the film by far. But, the concession stand owner played by Song Gang-ho (‘Memories of Murder’, ‘Joint Security Area’), whose daughter the monster abducts, isn’t the kind of hero you might expect. Director Bong has described him as “not retarded, but having what could be called subtle differences with a normal person.”
Bong’s fans would take this for granted - the director often slips comedic scenes into unexpected genres as he did in ‘Memories of Murder’, his award-winning comedy thriller about a serial killer. That film was the top movie in Korea in 2003. On tap for equal success, ‘The Host’ premiered at the Cannes Film Festival in April where it picked up a US distributor and received rave reviews - a reviewer for the French newspaper Le Monde even compared it to ‘Dr. Strangelove’.
The process of creating the visual effects was atypical as well. “Director Bong wanted to do everything digital,” says visual effects supervisor Kevin Rafferty, who led the team at San Francisco-based The Orphanage who created all 125 VFX shots. Rafferty and his team convinced the director to use a full-scale puppet for 10 shots; otherwise, the creature is always CG. Jang Hee-chul designed the creature, which looks something like a fish until she opens her huge mouth. “She has a five-way maw,” says Rafferty. “The top maw is an almost Alien / Giger-esque type of thing. It was a rigging challenge to make it open and close believably.” She’s asymmetrical with one good eye and one bad eye of different sizes. She can swim, walk and run, and can swing from her tail like a monkey. Fully stretched out, she’d reach around 45 feet.
A rig created in Maya made it possible for the creature to run on her front limbs using her tail as a stabilizer when she’s on land. “She’s like a carp mixed with a T-rex,” says Shadi Almassizadeh, CG Supervisor. Skin weighting and cluster systems for muscle dynamics and for the creature’s “lips” added realism and provided animation controls. Thirteen animators created the mutant carp’s monstrous performance.
She mutated because six years before the movie takes place, so the story goes, several gallons of formaldehyde dumped at the U.S. Army Base in Yonsan had polluted the Han River. Her skin, which has tuna belly texture, is an un-fishlike dark green.
|The CG creature from the Han River has one thing on her mind. The Orphanage’s Kevin Rafferty, visual effects supervisor for The Host, knows what that is.|
CGS:Is the creature always evil?
RAFFERTY: Yeah. It’s her nature. She lives to eat. When she found she had a penchant for human flesh, she started terrorizing people on the land.
CGS: Does she eat people during the movie?
RAFFERTY: Not on screen. We do see people sucked into her maw. She gets her prey and brings it to her den and stacks it up until she’s hungry. She’s a two-ton carp with a binge purge problem. She eats things whole and regurgitates what’s not digested before taking another feast. We see full bodies or skeletons.
RAFFERTY:Yeah, there are a couple of very gross shots.
CGS: So, did you create digital doubles?
RAFFERTY: For the main characters - the little girl heroine of the movie and her grandfather. And for the fat boy.
CGS:A fat boy? Such a target.
RAFFERTY: Yes, such a target. There are also a few regurgitation shots where she’s regurgitating prey in the den where we used a live action person. We make him all slimy as he comes out of the rig.
CGS:Did you use CG slime?
RAFFERTY:We used a tube with a rubber bladder at the bottom and kind of an elastic opening that somewhat resembled the creature’s inner mouth. We put slime in the rig and dropped a person through it. He got slimed as he came out. Those were fun moments.
Left: The Face control window that animators used to drive the emotional performance of the creature
|“We sent Jang Hee-chul, the creature designer, a file that was UV’d and he created the first iteration of textures by painting color diffuse maps in Photoshop,” says Almassizadeh. “Then, we had our texture map TD [technical director] create the other maps.” |
The studio’s Windows-based pipeline works like this: modeling, rigging, skinning, animation, and muscle simulation typically happen in Maya, texture painting in Photoshop, lighting in 3ds Max, rendering in Brazil, and compositing in AfterEffects. 2d3’s boujou often handles tracking. Particle and fluid effects might be generated in Maya, 3ds Max, or Houdini, although effects typically happen through plug-ins created for 3ds Max and rendered through Brazil. The Orphanage prides itself on finding clever off-the-shelf solutions to production problems. In the ‘The Host’, those problems were water and fire, both involving interaction with the creature that emerges from the river.
During the course of the film, two major things happen to the creature: The U.S. military attacks her with a secret chemical weapon, Agent Yellow, and, later, she catches fire.“We had three textures for her,” Rafferty says. “Her normal dark green skin that has been untouched by human hand. A blistered look when she gets doused with Agent Yellow. And, once she’s set on fire, we charred her underlying green and blistered textures.”
The Orphanage crew began modeling the creature and working on the effects in June, two months before filming began in Korea. “We had the storyboards; we knew what we had to develop before we started shooting,” says Rafferty, who was on set in Korea for three and a half months, from August through mid-November. “We finished the look development while we were filming.” Rafferty downloaded work from The Orphanage’s ftp site to his PowerBook, which he took to the set so that director Bong could sign off on the creature and the effects. “Once we had the creature rigged, we started showing him run cycles, walk cycles and swim cycles,” says Rafferty, “and before I got back, we showed him animation shots.”
On-set editing and a willing production crew helped make that possible. On set, an editor using a 17-inch Powerbook imported footage directly from the film camera’s videotapes into Apple’s Final Cut Pro. “The director could quickly decide which take he wanted because 30 seconds after the cut, he could see how the shot flowed in the sequence,” says Rafferty. “At the end of the day, he’d refine the edit and trim the shots to within a six-frame handle. We’d ship the shots on Firewire drives to San Francisco. The Orphanage could have the plate a week after Director Bong said, ‘Yes, that’s the plate.’”
Almassizadeh and some of the sequence supervisors also worked on the set in Korea. “The biggest thing for us was to shoot it right,” says Almassizadeh. “And the neat thing was that we were not taken for granted. The crew was learning about visual effects. The producers said, ‘Whatever you want, we’ll do it for you.’ It was remarkably different. Everyone on the set, from the production assistants to the director, worked 110% to make a good project. No one said, ‘It’s my time to sleep, or this is my coffee break.’”
This helpful willingness inspired Rafferty and Almassizadeh to ask the camera crew to shoot the HDRI chrome spheres, and the result had a huge impact on the production process later. Usually, the visual effects crew places the chrome spheres on the set or location after principal photography has finished, and they shoot the spheres with digital cameras. On this production, the Korean crew shot the chrome balls on film. “Within two minutes, they changed the lens and we could get a 4K resolution plate of the chrome ball,” Almassizadeh says. “It halved our lighting time later.”
The filmed plates of the chrome ball gave lighting crew the exact lighting direction and reflections captured in the live action shots. “When we put our digital creature in the plate the usual variables weren’t variable,” says Almassizadeh. “We never lit from the wrong angle.” Also, the chrome balls provided all the exposures they needed for global illumination. “They’d roll two seconds for each exposure for each plate,” says Almassizadeh. “It’s difficult to balance your white point on a digital camera compared to what the director of photography did on film, but we got that for free.”