Issue: Volume: 30 Issue: 3 (March 2007)

The Art Of WAR


In 480 BC, King Leonides led 300 Spartans on a suicide mission against Persian King Xerxes’s massive armies. The resulting legendary Battle of Ther­mopylae has inspired soldiers, writers, poets, filmmakers, and one graphic novelist, Frank Miller, whose ferocious illustrations retell the ancient battle in a heroic, modern style.

To adapt Miller’s acclaimed graphic novel for Warner Bros. Pictures’ film 300¸ director Zack Synder chose a technique adopted earlier by co-directors Robert Rodriguez and Frank Miller for Sin City. With the exception of one location shot of actors on horseback, Snyder filmed the entire movie in 61 days on bluescreen sets and stages in Montreal.

“The film is about Frank Miller’s book, not about history,” says Chris Watts, visual effects supervisor. “No location would work. We couldn’t shoot in Greece. We couldn’t shoot anywhere. So, we shot it against bluescreens and made the backgrounds exactly the way we wanted them from scratch.” Ten studios on three continents in four countries created the backgrounds, extended the armies with CG warriors, and added other visual effects. Postproduction took nearly a year.

Visual effects art director Grant Freckelton of Animal Logic (Sydney, Australia), however, was involved from the beginning. The production pipeline started with his concept sketches created in collaboration with production de­signer James Bissell, Snyder, and Watts; the concept sketches helped cinematographer Larry Fong understand how to shoot the actors on the bluescreen stages. Fong used film cameras rather than digital ones to create numerous scenes with slow-motion action: Synder often shot scenes at 150 frames per second (fps).

After Fong filmed each scene, the film was developed, scanned, and turned into hi-def QuickTimes. Freckelton then combined shots of the live-action actors with detailed concept paintings to create still frames. “We put those on a Web site we called Leo, for all the vendors to use as reference,” says Watts.

In addition to those reference shots, Freckelton worked with Watts to create style guides. “It became obvious that we needed those once the visual effects companies began ramping up,” says Freckelton. “At first, we tried to explain what we wanted verbally, but we got blank stares.”

The style guides were placed on the Web site, as well. “When you’re making an entire world, you need something consistent or people get confused,” says Watts. “We had skies, trees, rock textures, blood, just about everything you could imagine.”

Much of the visual effects work centers on the battles, which take place over three days of fighting in one location—the narrow mountain pass of Thermopylae. “There are four major battles, so that became one way to break up the work,” says Watts. Animal Logic took the first battle; Hybride Technologies (Piedmont, Quebec), the second; Hydraulx (Santa Monica, CA), the third; and Pixel Magic (Toluca Lake, CA), the fourth.

“All the battles happened in the same place but at different times of day,” says Watts. “So rather than spend time and money making the scenes all look the same, because the tenor of the story in each battle is so different, we decided to embrace the differences from each vendor. We allowed everyone to go in their own direction as long as they stayed within the production design. I think it made a more interesting movie.”

Smokin’ Oracle

The first scene Synder shot, though, was not a battle; it was the “dancing oracle” sequence, and for that, the studio Screaming Death Monkey created the effects. “The oracle is supposed to be possessed by a drug they wave around, so we shot her under­water against bluescreen,” says Watts.

Jeremy Hunt led a crew of approximately six people at Screaming Death Monkey who extracted the writhing oracle with flowing red hair from the water, and from shots filmed on the bluescreen stage, wrapped smoke around her, extended the sets, and added backgrounds.

They started with matte paintings for the sky and 3D geometry for the large hand that the oracle sits in, using NewTek’s LightWave to model the hand. “Grant Freckelton and Chris Watts gave us specific frames that had the flavor, feel, color, palette, mood, and everything we needed to have a solid starting point for the shots,” Hunt says. “We knew where the horizon line was, where the clouds were.”

Next, working in Autodesk’s Inferno, they “pulled the keys,” that is, removed the oracle from the water and bluescreen stages, and adjusted her skin tones and lighting. Then, they moved into Eyeon Software’s Digital Fusion to combine smoke elements with the filmed elements. To form the smoke elements, the team applied dynamics to long rectangular strips of geometry in LightWave. “They looked like pieces of cloth blowing in the wind,” says Hunt. “Then we morphed the entire structure through a bone chain to get a smoky movement.”

Because each section of the bone chain could rotate and change its angle like the bones in a cat’s tail, animators could wrap smoke around the oracle. Once the animators had moved the cloth strips into position, effects artists applied procedural textures and filmed elements to create a smoky look. “We also used Digital Fusion to polish the effect and grid warps to further position the smoke,” Hunt says. “We had enough time to polish it to a standard we usually don’t get to do. It was a great experience.”


The oracle was filmed in a water tank. CG artists added the computer-generated

backgrounds and smoke wrapping around her later in postproduction

Battle One: Animal Logic

Animal Logic first created a proof of concept test for Synder long before production began, but the postproduction team of approximately 50 artists began work on their battle, an eight-minute sequence with 176 shots, in November 2005.

They started with “temp” sequences. “We did a low-res projected cyclorama of the Thermopylae environment—a big canyon by the sea that’s surrounded by cliffs,” says Kirsty Millar, visual effects supervisor. At one end of the canyon are the “hot gates,” a narrow opening where the Spartans gather. At the other end is the “knobby bit,” where the Persians camp. When work began on the real shot, however, everything became CG. For this, the team used Autodesk’s Maya, Pixar’s RenderMan, and Apple’s Shake and Final Cut Pro.

“The ocean was CG,” Millar says, “but we used live-action elements for the waves crashing against the rocks and the water interacting with the land.” Shaders on geometry provided close-up detail for the cliffs, with projected matte paintings standing in for the mid and wide shots.

The painterly sky was a 2D effect. “We had a background cyclorama with separate live-action cloud elements individually rotoscoped, animated, and warped on top, and then on top of that, we added what we call the coffee-stain element,” says Millar. Artists blended that element, blotting paper with coffee thrown onto it, into real clouds in compositing.

Each studio had its own method of creating graphic blood. For its part, Animal Logic started with live-action elements of squibs (small explosions that burst balloons filled with blood) shot using a Photosonic camera at 300 fps. Artists combined those elements with practical blood elements from the studio’s library and with particles—2D particles generated with Autodesk’s Flame and 3D particles generated in Maya—to create libraries of blood elements for the compositors.

Similarly, Animal Logic developed libraries of dust and debris elements that compositors used to heighten the live-action battle and give it dimension. For the dust and debris, the effects artists created sprite-based particles with animated textures generated in Maya’s fluid solver. “We rendered everything at high resolution, so the compositors could play with the elements as needed,” says David Hyde, 3D artist. To add a comic book effect, the crew rendered the particles in black and white with very little motion blur; compositors added the color.

To swell the ranks of live-action Persian infantry and cavalrymen, the studio used Massive’s software. “Our biggest shot had 30,000 Massive agents,” says Hyde. Each agent had three levels of geometric detail and three levels of shading detail. To control individual characters, Ian Watson, a Massive TD, wrote a program that pulled information from the Massive simulation and rebuilt a bone structure in Maya for animators to use. Compositors then layered that character into the action. To shower the battling live-action and CG soldiers with arrows, the 3D team instanced particles.

One of the studio’s most difficult shots involved multiple cameras and multiple zooms. “They strapped three cameras and three lenses together and shot the live action at 100 frames per second,” says Hyde. “Then, they took the three sequences and merged between them in post using frame rates varying from 24 frames per second to 100 frames per second. The sequences ended up being 3000 frames long.” During the shot, King Leonides (Jared Butler) swings through the canyon while chopping off heads, and the Spartans hack and slash through charging Persians. The camera follows Leonides from close to midground to distant, with the frame rate changing throughout.

The studio generated a 3D camera in Maya from the merged sequence, through which they rendered 3D elements—dust, arrows, the cliffs, the crowds, and so forth—using their MayaMan as a translator into RenderMan. “We 3D tracked only the wide lens, worked out the offset of angles of mid and close-ups from that, and morphed between them in Shake to line them up,” explains Millar. “The shot had around 20 zooms, so we had 20 morphs at motion-interpolated high speed. It’s a long shot, very captivating. This was a fantastic project for us. It’s unlike anything we’ve seen before on screen.”

Detailed style guides that included samples of skies, trees, rock textures, blood, and so forth helped maintain an
overall consistency even though 10 studios worked on the project
.

Battle Two, Plus: Hybride

Daniel Leduc, visual effects supervisor at Hybride Technologies, began working with Watts in September 2005, and was soon leading a team of 80 artists—45 in 3D, 35 in compositing—who worked on about 540 shots in 20 scenes.

300 is the fifth movie for which Hybride has created backgrounds to complete films shot entirely on bluescreen stages. Most recently, the studio worked on Sin City. “They had bigger sets for 300 than for Sin City to try to minimize the problems with contacts,” he says. “And 300 is closer to photoreal. But, technically, it’s the same preparation. You have to do 3D tracking on every shot and extrapolate the matte, sometimes generate mattes for layering because you need to insert objects between [live-action] characters or objects. The look at the end, though, is very different. That’s the beauty of this kind of approach.”

To build the environment for their battle, which takes place in the same canyon that Animal Logic created, Hybride referenced European Calanque mountain ranges near the Mediterranean, steep rock formations that rise from the sea and resemble fjords. “Every scene was different,” says Philippe Theroux, 3D supervisor, of battle two. “For some of our scenes, we textured everything in CG with Softimage XSI, for some we used projections. The texture projections give a 2D look even if they’re on a 3D background, which helped keep the connection between the movie and the book.”

Like Animal Logic, Hybride mixed coffee-stain “paintings” with real clouds for the skies. For the water, the artists composited practical elements into CG water created in XSI. Unlike Animal Logic, Hybride animators keyframed the soldiers, rather than using crowd-sim software. “We used internal scripts based on keyframe animation for the final charge—the scene with thousands of CG characters behind the first row of soldiers,” says Theroux.

To create the blood, the studio photographed paint splashes on paper, then animated layers with the digital photos in 2D. “That way, we kept the Frank Miller look because it’s a 2D look,” Leduc says.

In addition to the second battle, Hybride worked on several other sequences, including an early “wolf” sequence. The setting is Greece’s Pindus Mountain, at night, and except for the live-action child, the sequence is entirely 3D. “We used a stylized frame of the wolf and the environment from Frank Miller’s book as reference,” says Leduc.

Modelers, riggers, and animators worked in XSI to create the stylized wolf, using an XSI fur shader to render the fur through Mental Ray. “To reveal the shape of the wolf in the dark background, we used the falling snow,” says Theroux. To do that, they wrote special plug-ins to stick snow particles onto the wolf’s fur.

For shots of the Persian camps, Hybride added people and boats to the beach, soldiers walking between tents, and, for the night shots, fiery torches. The fire is real; the people are CG. For soldiers in formation, animators matched the actions of the actors in the first rows, and the effects artists used cloth simulations to duplicate the movement of their capes. To create the digital actors, Hybride cyberscanned the live-action actors and photographed them in various poses to create and texture the CG models. During the battle scenes, rotoscopers gave compositors rough rotos of all the live-action soldiers’ hands so the compositors could replace every sword and spear. “This kind of film takes a lot of patience,” says Theroux. “But it’s very creative. We were like painters starting with a brand-new canvas.”

To create the skies, compositors blended a scan of blotter paper with coffee
thrown onto it into animated layers of photographic elements
.

Battle Three: Hydraulx
 
As did the other studios, Hydraulx created the environment for its battle, which happens over the course of a day, and heightened the action in its own way. But, this battle included something extra: three elephants and a rhinoceros.
A team of approximately 30 artists worked on the studio’s 62 shots for nearly a year. “It wasn’t the amount of shots,” says Chris Wells, CG supervisor, “it was the number of frames. We had one shot that was 2700 frames, and we had to work on it at scan length because we had so many CG elements.” That is, even though the shot was edited down to 900 frames, the studio worked on all 2700 frames. If Hydraulx hadn’t added the CG elements at scan length, the time warp—the various speeds edited into the 900-frame shot—couldn’t have changed without changing the CG elements. Moreover, the camera was moving 360 degrees during the shot. And, it wasn’t the only shot like that.

“We had a second shot that was 1900 frames,” says Bill Kunin, lead Inferno compositor. “We didn’t do anything particularly different in terms of pipeline procedures for compositing. It just took longer.” Hydraulx used Maya for 3D, Mental Ray for rendering, and Inferno for compositing.

Because of the 360-degree camera move, Hydraulx modeled a giant set in Maya rather than constructing small background sections from camera views, as they might have otherwise. They fit tracked, live-action footage into this giant set. Mental Ray shaders added textures to the rocks at the hot gates and created the ocean below. All the animals are CG, as are many of the soldiers.

Animators keyframed the rhino and elephants using special rigs and muscle systems developed in Maya. “The rhino moves differently than people expect, plus we had armaments,” says Wells. “The rig got complicated fast.” Because the shot was filmed at high speed, animators performed the rhino as if it were moving in slow motion. “Time warping wouldn’t have looked right,” says Wells. “When you time-warp CG, it looks steppy.”

The elephants, which wore baskets with animated CG characters inside, needed a mixture of 24 fps animation and slow motion. “The most challenging thing was that they were about 24 feet tall, so we had to cheat their body mass and leg length,” says Wells. “And the shot when we knock the elephants off the cliff was difficult. The elephants are rearing back, getting attacked, occupants fly out and bounce off the rocks. It was all hand animated.” Particle effects helped sell the shot of an elephant hitting the CG water at the bottom of the cliff.

To animate the soldiers, the studio put running and walking Massive agents in the background in wide shots, hand animated sequences of Persians and Spartans replicated through the rendering pipeline in the midground, and mingled CG soldiers into live-action soldiers to thicken the real army. “We modeled every type of character and made a library of their weapons, clothing, armor, and so forth that we could propagate into the scenes,” says Wells. “Then we hand animated about 20 cycles of soldiers for the good old-fashioned crowd duplication.” Syflex software moved the Spartans’ capes.

For blood, Hydraulx used Next Limit Technologies’ RealFlow. “We did real fluid simulations,” says Wells. “We animated proxy geometry for the victims, and determined where we needed to emit blood from.” One problem that all the studios faced was especially tough for Hydraulx. The studios called it “the crush.” Everyone knew that the contrast levels in their shots would be exaggerated, that is, “crushed,” during the Digital Intermediate process to give the film more of graphic novel look.

“They wanted such an extreme look, we had to give them something relatively flat so when they put on the extreme contrast, it looked right,” says Kunin. “It was hard trying to make the rhino and elephant look good, not knowing what the final look would be.” 

Adds Wells, “The rhino had between 20 and 36 layers of CG that we ran through the comp with our pseudo color corrector, to see how the comp would hold up when they put the contrast on. A two percent change in value could make the scene go to hell.”

The elements that combined to create a sequence in which a child fights a wolf include:
(top left) the CG background; (top right) the 3D wolf with guide hair in place;
(middle, left) the bluescreen shot of the actor; and (middle, right) the actor composited with the
CG background. Bottom shows the rendered wolf comped into the shot.
 
 The oversized CG elephant and the basket spilling out CG
people were all hand animated to tumble off the CG cliff into digital water
below in slow motion and at 24 frames per second.
 
Battle Four: Pixel Magic

The three-minute sequence starts with Xerxes and his army of Persians surrounding Leonides and his remaining 70 men at the base of the 200-foot-tall hot gates. It took a team of artists at Pixel Magic around nine months to create the 105 shots.

“Our environments were a combination of CG ocean, CG hot gates, and skies that were mostly a combination of live-action elements, compositing, and color-timing tricks. The distant mountains were sometimes a matte painting,” says Raymond McIntyre Jr., visual effects supervisor.

To create the ocean, the studio built meshes in Maya and LightWave, and ran a RealFlow simulation through them. “We isolated the elements we liked—the chop, swells, and highlights—and combined those in compositing,” says Tyler Foell, digital effects supervisor. For artistic reference, the studio hired a cameraman to shoot oceans from the bluffs along the California coastline from San Diego to Santa Barbara. As the sequence progressed, though, Watts pushed for a stylistic look. “We had lots of haze, lots of highlights kicking off the ocean to give it an early-morning look,” says Foell. Similarly, the hot gates, which they had given extra geometric detail with Pixologic’s Zbrush, became smoother as the shots progressed.

The opposite happened with the sky. “We started with a specific style guide for the skies, which had a painterly look,” says Foell. “It was around two-thirds real and one-third painted with coffee stains. During the last three months, it went to 90 percent realistic with color correction, using multiple sky elements and 10 percent painterly.”

For painting, the studio uses Adobe’s Photoshop. In addition, Pixel Magic’s tool kit includes LightWave, Maya, Zbrush, 2d3’s Boujou, Andersson Technologies’ SynthEyes, Pinnacle Systems’ Commotion, Shake, and Adobe’s After Effects.

In a shot near the end of the film, the camera looks down on the dead Spartans, then lifts up and pulls away. “We had to add bodies and arrows,” says McIntyre. “Even though the shot is mostly live action, after the crush was applied, it looks like a painting.”

As with the other studios, film speed and the crush affected Pixel Magic’s work in unusual ways. “It took a while to get the hot gates and the ocean to look like we wanted, but the real fiddling was in the 2D portion of the work,” McIntyre says.

The fast film speed, for example, affected the bluescreen extractions. “When you shoot overcranked [at high speed],” McIntyre explains, “you need more light to expose correctly, and if you don’t have enough light, grain becomes a problem. If the film grain is as big as the hair on the mane of a Spartan’s helmet, it takes a long time to make sure that hair doesn’t pop.”

And the 2D work went beyond compositing bluescreen actors into the synthetic backgrounds. For example, Pixel Magic rotoscoped areas of Leonides’ face, helmet, the mane on top of his helmet, his shield, his clothing, and the people behind him, and tracked mattes for the motion in every live-action shot so the crush could be applied independently to each area. “During a dialog between Leonides and a messenger, the crush had to be the same even though they are in two different lighting conditions,” McIntyre says. “If it weren’t for the crush, we would have left the lighting from the DP [director of photography] the way it was.”

Beyond the Battles

In addition to the battle-charged studios, Scanline VFX (Munich, Germany) created a sequence in which people looking out over the ocean notice crashing boats below. “It’s a big shot; a super-cool scene,” says Watts. “We picked Scanline because they are good at doing large-scale water using true fluid simulations, and they are also good at making the spray and the water one uniform thing, not two elements slapped together.”

To extend a council chamber for a scene at the end of the film, Watts picked Buzz Image Group (Montreal). “They did backgrounds, comps, and a little bit of set-extension work,” he says. “Also, Amalgamated Pixels (Westlake Village, CA) did a shot with a guy falling into a well, and Lola (Santa Monica, CA) and Technicolor (Burbank, CA) created the hunchback’s eye.” In addition, Meteor Studios (Montreal) worked on a field sequence.

“The nice thing about shooting models or live action is that you have a lot of happy accidents,” says Watts. “When you do things digitally, the happy accidents usually don’t happen. But, by giving people the parameters of the world and then letting them have a little freedom, people can put their own spirit into the production.”

Indeed, considering that of the 1500 shots in 300, 1300 had some kind of visual effect, whether optical or digital, perhaps the most interesting effect of all was that each studio brought its own artistic style to the film.


Each studio created ocean scenes using different tool sets and techniques ranging from full fluid
simulations to practical elements composited into CG water.
 

Barbara Robertson is an award-winning writer and a contributing editor for Computer Graphics World. She can be reached at BarbaraRR@comcast.net.

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