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Making Feature Film VFX Look as Easy as Pi

By Christine Bunish

Pi and the tiger, animated by Rhythm & Hues, learn to rely on each other to survive an epic journey. Photo: Rhythm & Hues;  Trademark and Copyright Twentieth Century Fox Film Corporation. All rights reserved.
Pi and the tiger, animated by Rhythm & Hues, learn to rely on each other to survive an epic journey.
Photo: Rhythm & Hues;
Trademark and Copyright Twentieth Century Fox Film Corporation. All rights reserved.

If watching Ang Lee’s Life of Pi was an extraordinary experience for moviegoers, imagine the challenge of creating many of the film’s amazing visual effects. “Ang blew W.C. Fields’ ‘never work with children or animals’ quote out of the water and stuck [stereo] 3D on it,” laughs Bill Westenhofer, VFX supervisor at Rhythm & Hues Studios (R&H), Los Angeles (www.rhythm.com).

Indeed, an Indian boy (played by Suraj Sharma) and an astonishing menagerie (an orangutan, hyena, zebra, flying fish, whale and a tiger named Richard Parker) form the core of Pi’s tale of shipwreck and survival, which the Academy Award-winning director opted to shoot in stereo 3D. Life of Pi is a Best VFX winner at the BAFTAs and Oscar nominee also has netted a Critics’ Choice Award for its VFX, plus honors from Las Vegas, Phoenix and St. Louis film critics.

Rhythm & Hues VFX Supervisor Bill Westenhofer on the high seas.
Rhythm & Hues VFX Supervisor Bill Westenhofer
on the high seas.

But the VFX for Life of Pi is about more than triumphing over the historical bugaboos of children and animals. It’s also the story of how R&H LA marshaled an international roster of artists and animators, distributing work to its studios in Mumbai and Hyderabad, India, which handled close to 40 percent of the animation, lighting and compositing; and its offices in Kuala Lumpur and Vancouver. It’s a lesson in coordinating and supervising a host of other VFX vendors, including MPC (The Storm of God sequence) and Crazy Horse Effects (matte painting and period work). And it’s the hope that audiences recognize that VFX go way beyond the technical and the wow factor.

“Ang said he wanted to make art with us,” Westenhofer recalls. “That was inspirational and really resonated. Ang has a strong aesthetic that’s grounded in reality. Using photography creatively was the most rewarding part of the movie for us.”

R&H’s involvement in the film began in summer 2009. Since the ocean appears in more than three-fifths of the film, finding a way to deal with the continuing presence of so much water was a fundamental challenge.

“Creating digital water is still really hard, and Ang challenged us to make the ocean look as real as possible,” Westenhofer recalls. “We went out overnight in heavy seas on a Coast Guard cutter in Taiwan. We were hanging over the ship’s railing studying the white water and foam; Ang insisted on that level of detail.”

The tiger Richard Parker, animated by Rhythm & Hues, is a central character in the incredible Life of Pi. Photo: 20th Century Fox Trademark and Copyright Twentieth Century Fox Film Corporation.  All rights reserved.
The tiger Richard Parker, animated by Rhythm & Hues, is a central character in the incredible Life of Pi.
Photo: 20th Century Fox
Trademark and Copyright Twentieth Century Fox Film Corporation.
All rights reserved.

A 75×30-meter tank was set up in Taiwan and surrounded by bluescreens for plate photography. A theme park company built a series of 12 caissons to vary wave patterns in the tank achieving a personal best four-foot swell in 12-second periods. Image capture was done with ARRI ALEXA cameras mounted in Cameron|Pace Group Fusion 3D rigs. Claudio Miranda, who has an Oscar nomination of his own, was the cinematographer.

[Left, From Top to Bottom] Rhythm & Hues makes Pi’s boat and the tiger, Richard Parker,  materialize on digital water.
[From Top to Bottom]
Rhythm & Hues makes Pi’s boat and the tiger, Richard Parker,
materialize on digital water.

Shooting the tank sequences in 3D on a Technocrane often meant there were no reference points to track to. So two witness cameras were set up at different angles and timecode synchronized. R&H artists tracked the boat in the witness cameras first, not the main camera, to get the boat, its motion and the environment all correct.

“The thing that made me most nervous at the time was blending the tank water in stereo with digital water – getting the patterns and geometry to match,” admits Westenhofer. “We shot a lot of reference video of the waves in the tank so we could calibrate our wave tools and make sure they were as physically accurate as possible. For every wave beat the artists would write in the frame numbers and code the wave functions from low frequency to high. You could see the wave start in the tank and continue into digital with a nice blend at the edge.”

In some sequences, such as Pi fighting big, rolling swells, R&H replaced all the practical water with an angry digital ocean. “Even then they’d still shoot in the tank to capture the motion of Pi in the boat,” he recalls. “It was so much more genuine with that interaction.”
For water tools, R&H adapted Side Effects’ Houdini software with a custom proprietary shader and stereo visualizer; rendering was done in Side Effects’ Mantra.

All the skies were HDRI photography. “When we were bidding the project, I naively thought there must be libraries of HDRI skies out there, but there was practically nothing,” says Westenhofer. “We had people on the roof at R&H shooting skies, people on vacation in Hawaii shooting skies. Now we have a pretty enviable library.”

What viewers saw in the film was an amalgam of a lot of different photographic-based skies that met Ang’s desire to choose art and aesthetics over pure CG solutions.

One of the deciding factors in R&H being awarded the VFX for Life of Pi, says Westenhofer, was Ang’s recollection of R&H’s animation of Aslan the lion in The Chronicles of Narnia: The Lion, the Witch and the Wardrobe. “Ang had seen it and wanted to know if a digital character would look more or less real in 3D.”

R&H’s stunningly photoreal Richard Parker, the tiger, began with eight weeks of rehearsals with a real tiger and 100 hours of video reference footage to help animators deliver a true performance on screen. “We had an early discussion about using the real tiger, but of 170 tiger shots only 14 percent are real,” says Westenhofer. “Ang held our feet to the fire to make sure we could match the real animal. The trainer had worked with tigers for 30 years and we got incredible reference of how the tiger responded to him.”

In crafting the CG tiger, it “was important not to anthropomorphize anything, so we relied on the reference to keep us honest.” It was key to capture him behaving as tigers do, not as we think they do. For example, “when they’re scared they act as nonchalant as possible – aloof,” says Westenhofer. “A calm tiger means a nervous tiger. The goal was to create a real tiger character in unusual circumstances who behaved in genuine, tiger ways.”

The tiger, Richard Parker, animated by Rhythm & Hues, in the thick of a school of flying fish. Photo: 20th Century Fox Trademark and Copyright Twentieth Century Fox Film Corporation.  All rights reserved.
The tiger, Richard Parker, animated by Rhythm & Hues, in the thick of a school of flying fish.
Photo: 20th Century Fox
Trademark and Copyright Twentieth Century Fox Film Corporation.
All rights reserved.

R&H’s proprietary Voodoo VFX toolset was used to animate Richard Parker and the proprietary Wren for rendering. “We’ve built up Voodoo for years and years and have taken advantage of it for all the animals we’ve done in the past, so we were starting from a really good place,” Westenhofer notes. “We just had to spend time on the details.”

And what details. The technology for rendering fur has advanced to the point where Richard Parker was mostly raytraced and fully diffuse-reflected his environment. The ability to sub-surface scatter through fur softened the texture and allowed light to penetrate deeper.

Director Ang Lee on the set of Life of Pi. Photo: Jake Netter; Copyright Twentieth Century Fox Film Corporation. All rights reserved.
Director Ang Lee on the set of Life of Pi.
Photo: Jake Netter; Copyright Twentieth Century Fox Film Corporation. All rights reserved.

Richard Parker’s performance rig “was a complicated as we’ve ever done,” Westenhofer reports. “There were as many controls in his paws as in a face in the past.” The rig also had to take into account a tiger’s singular anatomy. “They’re a solid mass of muscle surrounded by loose, baggy skin. So we needed a two-pass skin system to pull that off.”

A wet tiger was the ultimate challenge requiring numerous passes for R&H to integrate water simulations run in Houdini with proprietary fur, muscle and tiger.

What drove the studio to push Richard Parker beyond previous creature animations was Ang’s quick approval process that enabled them to get decisions on the big points “then spend two more weeks on minutiae.”

The same kind of care went into the other creatures, as well. “It took one year and 10 million hairs to build the model of Richard Parker and six to eight months for the other models,” explains Westenhofer.

The orangutan proved to be particularly challenging given the ape’s close relationship to humans. “Many times we based the performance on reference footage, and Ang questioned if it was ‘too human,’” Westenhofer recalls. “Then we’d show him reference of the orangutan doing that thing. They’re so closely related to us that a lot of their behavior seems like human gestures.” A small concession to anthropomorphism: the orangutan’s nod to Pi before the hyena moves in for the kill, which parallels the emotion in Pi’s mother’s demise.

Animating the meerkats was “lots of fun. We saw every episode of Meerkat Manor – we were just going to watch one and got hooked,” Westenhofer said. “We put meerkats doing little fun things that cracked us up in the background where nobody will notice them.”

Ang Lee (left) and Bill Westenhofer (right) on the water tank set for Life of Pi.
Ang Lee (left) and Bill Westenhofer (right) on the water tank set for Life of Pi.

Tens of thousands of flying fish comprised one of the most complex Massive software simulations R&H had ever tackled. Special coding was necessary because “in Massive’s initial form there was no way to distinguish the difference between the fish’s different behavior below the water and above,” he explained. “As the fish are gliding, they can strike their tails on the water to get up to speed again.”

The whale breach was completely digital with the bioluminescence of the ocean surface based on reality. “Ang took us on a boat trip off southern Taiwan in the middle of the night,” says Westenhofer. “The boat stopped, and there was an incredible glowing cloud of bioluminescent plankton all around us.” R&H tapped Houdini with assistance from Autodesk’s Naiad to give a sense of the water compressing the glowing creatures.

Lost at sea, Pi begins to make an extraordinary connection with the Bengal tiger, Richard Parker, animated by Rhythm & Hues. Photo: 20th Century Fox Trademark and Copyright Twentieth Century Fox Film Corporation.  All rights reserved.
Lost at sea, Pi begins to make an extraordinary connection with the Bengal tiger, Richard Parker, animated by Rhythm & Hues.
Photo: 20th Century Fox
Trademark and Copyright Twentieth Century Fox Film Corporation.
All rights reserved.

Although R&H had experience with stereo 3D features, Life of Pi was Westenhofer’s introduction to the technology. “I was surprised where the difficulties were and where things were easy,” Westenhofer said. “The water and the tiger were pretty straightforward. But in the compositing realm, the rotoscoping had to be so precise – you’d go to the dailies and look at a shot and through the artist’s eyes you’d realize you have to go back and keep working that edge to avoid the stereo movements that give a feeling of the wrong depth.”

He realized early on that shooting stereo 3D meant “we couldn’t rely on element shoots,” that “things had to be shot in exact stereo space. Bluescreens were harder. We had to be way more accurate from an animation standpoint – we couldn’t just work in camera space; we had to work in 3D space so we could see the contortion of an animal.”

The tank in Taiwan, Surrounded with bluescreens, where practical water sequences were shot.
The tank in Taiwan, surrounded with bluescreens, where practical water sequences were shot.

Although Life of Pi already has won some VFX awards and is a leading contender for more, Westenhofer hopes that Ang Lee’s desire to “make art” with R&H heralds a change in the perception of visual effects. “VFX gets lauded with technical awards for the gee-whiz things. But what I hope the industry and public appreciate with this film is that in the hands of a director like Ang, VFX can be a major artistic part of a film.

Capturing boat movements on a bluescreen stage.
Capturing boat movements on a bluescreen stage.

“Ang knew what he wanted but didn’t hamstring us. He wanted an operatic sky, a liquid gold morning, then let us go way and find it and come back to him. VFX purveyors are artists, and I hope they get recognized beyond their technical ability to create explosions.”

Personally, Westenhofer takes away memories of Life of Pi as “a great project with a lot of fun people. I got to spend eight weeks with a tiger, go out on a Coast Guard cutter on the high seas, and watch bioluminescent plankton. You don’t get those opportunities in another line of work.”


March 3, 2013