Issue: Volume 34 Issue 6: (June/July 2011)

The World Is Not Enough

By: Barbara Robertson
In a world populated with cars rather than people, the sports heroes would be the race cars. Heroes like Lightning McQueen, a smooth-looking stock car that almost won the Piston Cup after losing himself in Radiator Springs, that small, forgotten town on Route 66.

Cars, an animated feature from Disney/Pixar, followed McQueen’s journey to checkered-flag fame and true friendship with, especially, a tow truck named Mater and a hot sports car named Sally Carrera. The blockbuster scored an Oscar nomination for best feature animation in 2006, cranked up nearly $462 million in worldwide box-office revenue, and brought home a reported $5 billion in merchandise sales.

Five years later, McQueen and his Radiator Springs-based racing team are back in the headlights. The little desert town wasn’t big enough for the dynamic star, and especially for writer/director John Lasseter. “When I was doing international publicity for Cars, I’d be in Tokyo, Paris, Italy, or Germany and laugh to myself, thinking, ‘What would Mater and McQueen do in this place?’ ” Lasseter says. “And, when I was in Barcelona on an international press junket, I went to my first Formula 1 race, and wow, was that cool.”

So, in Cars 2, McQueen accepts an invitation to compete in the first-ever World Grand Prix. Based loosely on Formula 1 racing, the competition sends the stock car, tow truck, and the rest of the pit crew around the world, but that isn’t the whole story. Along the way, Mater is mistaken for an American spy.

“In Cars, we had McQueen and Sally go to a drive-in and watch a spy movie,” Lasseter says. “The spy cars were the spies. We cut that from Cars, but we never forgot it. So in Cars 2, we have a spy movie within the movie.”

The main spy cars are Finn McMissile (Michael Caine), a British master spy who looks something like James Bond’s silver Aston Martin, and Holley Shiftwell (Emily Mortimer), a spy in training. McMissile makes a dramatic appearance in the opening sequence where, in James Bond style, he rockets from a boat in the ocean onto an oil rig in the North Atlantic. “For Finn McMissile, we started with drawings by Joe Ranft and created an English coupe with Italian touches,” says Jay Shuster, character art director. “Then we added headlight-to-air missiles and side guns.” Holley has a holographic screen and carries spy gear in her wheels. The spies’ antagonist is Professor Zundapp (Thomas Kretschmann), designed after the rare Zundapp Janus car and who, for some unknown reason, wants to stop Lightning McQueen from winning the Grand Prix.

In addition to these cars and the returning stars—Lightning McQueen, voiced again by Owen Wilson, Sally (Bonnie Hunt), and Mater (Larry the Cable Guy), among others—the film has 11 new race cars, with Francesco Bernoulli (John Turturro) driving a Formula 1 car as McQueen’s major competitor. “I delegated the early research to [co-director] Brad Lewis,” Lasseter says, “and he did a lot of the Formula 1 stuff. As the movie moved more into production, though, I started spending more time on it.”


Above left, layout artists designed a unique racetrack for each location, including Porto Corsa in this image and Tokyo on the previous pages. Above right, the artists incorporated various racing styles, such as a dirt section that favored rally cars. Then, they plotted each car’s position during the race. In both images, Lightning McQueen leads, with Francesco close behind.

For each car, the automotive designers followed Lasseter’s edict of “truth to materials.” “We still have to stretch some to get them to act, so we kept the mouth area simple,” Shuster says. “And, we moved windshields forward, shortened the cars, and made the wheels bigger. Francesco was hard because he has such a massive nose. He took four to five months of iteration.” McQueen even spent some time in the body shop for this film and came out with new wheels, new headlights, a new paint job, a bigger exhaust, and a carbon-fiber diffuser.

On the Road

As in the first film, animators took advantage of a driving system that helped them send the cars speeding down the racetracks, but still gave them the freedom to perform the cartoonish characters. “We refined the original system from Cars,” says Apurva Shah, supervising technical director. “That system had worked great most of the time, but the animators wanted the cars to do sharper turns.”

Layout artists blocked in the cars’ initial route using a point-based path system that worked with lightweight geometry for the cars and sets. “We would plot interesting curves and angles in the set, and how we would shoot them,” says Jeremy Lasky, director of photography for camera. “We thought about how the turns would work logically in the real world.”

The artists would drop points to create a path, the points would make a curve that shaped itself to the track, and the cars would follow the curve at a set speed. Generally, these race designers would create one main path through a track’s curves and angles, and then copy that path onto the other cars with slight variations. A tool that converted the path into the usual translations for each character gave animators more precise control.


At top, set designers built cars and car parts, designed in the art department, into landscapes and cityscapes to create a world in which automobiles, not humans, live. Porto Corsa is an imagined place on the Italian Riviera with hints of Monaco. At bottom, a breeze can blow through procedurally created leaves on the Champs Elysees trees.

To refine the shape of the racetracks as needed, artists in layout worked with their peers in the sets department who provided the building blocks for the tracks and the surrounding environments. “Our goal was to make sure the layout artists had the basic structure of the set design in a way to tell the story,” says John Halstead, sets supervisor.

Each track combined elements from different racing styles, and the tracks in each location varied wildly. “The challenge for this show was that the races go through individual cities and countries,” Lasky says. “And, we had to figure out how fast the cars go on the straightaway and in turns, and in what racing order. In the first film, we had big oval tracks.” For example, in one race, the story calls for Francesco to fall behind in the dirt section, built to simulate conditions in a rally race, and then catch up again.

Once they had blocked in the paths for all the cars through a race, the layout artists placed the cameras. “That was the real fun,” Lasky says, “to capture a race from different angles. John [Lasseter] would point to real races—how the courses are laid out and how the camera operators cover the course. We placed the cameras to make the most interesting angles.”

The crew sent several camera angles showing different aspects of the race to editors who cut them together to create a sequence. “We might have a shot of McQueen pulling ahead and another with neon reflected in his side,” Lasky says. “And John [Lasseter] would have his favorite shots. It was a process of refinement.” The process typically took four to six weeks per sequence. Once locked down—that is, once Lasseter approved the cut, the timing, and the camera—the sequence moved into animation and the set dressers replaced rough geometry with detailed sets.

Carification

Production designer Harley Jessup began the process of designing Cars 2 ’s 118 unique sets in 2006. “Because it’s a traveling movie, the number of sets is double that of our usual films, except for The Incredibles, which had 80 or 90,” he says. The world for Cars 2 is as global as our human world, but in the cars’ world, the “humans” are vehicles.

“John wanted everything to be as authentic as we could make it,” Jessup says. “The cities look like real places. But they have a car motif.”


Reflections became an ongoing lighting theme for Cars 2. In this image, set in Tokyo, the novice British spy Holley Shiftwell (at right), wearing an auto-body’s equivalent of a purple evening gown, charms Mater, the tow truck from Radiator Springs. Mater is the only character in the film that doesn’t reflect the world.

The tongue-in-fender architecture is evident throughout the film. A museum in Tokyo has a chrome bumper. The Big Bentley in London has a car grill behind its clock. And, the towers on the Houses of Parliament are spark plugs. Gargoyles look like cars, and cars replace people in murals and coats of arms. In Paris, car parts fill Les Halles, modeled after the original market. “We try not to be too heavy-handed with the ‘carification,’ ” says Halstead. “We try to add the car features in a way that sits quietly. If you’re looking for it, you will notice it, but we don’t want to detract from the characters.”

The four showplace sets are Paris and three cities with racetracks: Tokyo, London, and Porto Corsa, which references Portofino in the Italian Riviera with a touch of Monaco. Porto Corsa is bookended by one hill topped with a casino and another with a castle. “The [Porto Corsa] terrain has car features worked into it, but it looks like it’s carved out of rock,” Halstead says. “Sometimes we might take one of the characters, strip it down, and work it into the mountainside. In other cases, we might not have a car part available, so we would model up a spark plug or radiator cap from reference.”

Building Developers

Although the modelers built the landscape around Porto Corsa by hand, many of the film’s locations were fully 3D, created procedurally—Tokyo and London particularly, and the chase sequences with spy jets flying over cities. “For Ratatouille, we had created a big cityscape that first we rendered and then a matte painter painted on top, and then we added flickering lights for realism,” says Chris King, technical director. “That was a short sequence. Such an ad-hoc process would have been too expensive for this film.”

A technique for creating fully 3D cities, in which set dressers hand-place buildings of various sizes in a set and orient them to create a non-uniform appearance, wouldn’t have worked, either. “Apurva [Shah] had the idea of looking into algorithmic cities,” King says. “We wouldn’t have done those chase sequences otherwise.”

Thus, to create large areas in the 3D cities, the technical directors started with City­Engine, an off-the-shelf software program from Procedural, Inc. “We worked the product into our pipeline,” King says. “We started with background buildings in Tokyo. We took existing models of foreground buildings, chopped them into components, broke the area into city blocks, and populated the city blocks using rules to grow the buildings from the components. CityEngine stacked up our components at various heights. Then, we shaded the buildings using Slim in [Autodesk] Maya.” Rendering, of course, was through Pixar’s PR RenderMan.


Writer/director John Lasseter and his wife, Nancy, learned during a visit to Paris that couples are supposed to kiss when they cross the Pont Des Arts, thus inspiring this shot.

For Radiator Springs, the challenge was different: Pixar’s latest tools couldn’t deal with models created for the 2006 film (see “Car Talk,” June 2006). “We wanted to bring Radiator Springs over [for this film], but the way the surfaces work with lights is something we re-engineer on every show, and they are very different now than they were for Cars,” King says. “We had to replace the low-level routines in the shaders. So, we came up with scripts to go through all the shader code and make all the edits—the thousand instances of this one little thing that needed to be tweaked.”

The crew also used a procedural approach for vegetation, creating, as they did for hard-surface models, and libraries of elements. “We created everything, from huge landmarks, to pieces of trash on the ground, to the signage,” Halstead says. “We have a shot in the spy train that’s pretty cool in which Mater gets to see all the weapons the [bad] guys carry around with them. Vegetation also was big for us. Every place had unique vegetation. And, we had thousands upon thousands of graphics in this film.”

Using a hybrid approach that allowed art direction, the digital landscape artists created libraries of vegetation by first modeling a plant’s main trunk and branches with geometry to form a canopy shape. Then, they populated the branches with twigs and foliage using particles. “You could think of it as attaching little particles everywhere and instancing high-res geometry up close or low-res geometry behind,” Halstead says. “But we also had full connectivity throughout the trees, from branches to twigs and leaves, to make it straightforward to simulate wind and other forces. We tried to make it as flexible as possible.”

In a typical pipeline, the art department would create initial designs from storyboards, send those to layout, and then, once the director gave a sequence final approval, the set designers would add the detailed set dressing that adds richness to a scene. For this film, the schedule dictated a faster approach.

“We didn’t have time to wait for things to settle out in layout,” Halstead says. “We went full-steam ahead when we had approval on an initial [location] scout, so we could get something into the lighting department as quickly as possible. Layout creates a lot of shots, though, and many won’t be used, so to stay efficient and not work ourselves into the ground, we saved some shot-specific tasks, like camera dressing and paint, until we had the actual shots.”

King helped the crew manage the graphics, signs, stickers, and so forth, created by a group of artists working in Adobe’s Illustrator. The signs were especially important for Tokyo’s Ginza district, where Lasseter asked for so many signs that they hid the buildings.

“In the past, there was always a battle around getting the graphics into the shaders,” King says. “The artists wanted the shader guys to do the conversion and vice versa. And, we have to get a legal buyoff on every single graphic. That involved a huge amount of database work, which the coordinators had always managed by entering information into a database by hand. So, I wrote scripts that worked inside Illustrator that converted the EPS [Encapsulated PostScript] files to TIFF at a standard resolution. It showed up on a TD’s desktop ready to go, with the database entries created and with feedback to the coordinators. The TDs could change the resolution if they wanted. This is not as sexy as a beautiful, new global-illumination thing, but it generated a lot of positive feedback.”

Headlights

Director of photography Sharon Calahan was responsible for the lighting design, leading a team of 58 lighting artists, with another 10 people providing technical support. “The crew was excited because we had a wide variety of locations,” she says. “On Ratatouille, people never left the kitchen. No one got bored on this film.” Because the art department was busy with hundreds of characters and sets, Calahan created the key lighting for each sequence by painting over camera views from layout.

In addition to the scope, and because of the scope, her challenge was to create unique yet visually connected environments. “Reflections were a big part of the overall visual style,” Calahan says. Reflections in the world and in all the car bodies, of course—all the cars except Mater. “Mater doesn’t reflect the world around him,” Calahan says. “It’s a metaphor. He’s always who he is.”

For a party in Tokyo, Calahan added a layer of gloss to the entire scene, and outside the party, lighters hand-dressed each sign. “We also had wet streets in some shots, but not in races, because the cars would skid,” she explains. “It doesn’t rain in the Riviera, but if I could have had rain, I probably would have. In addition, I used pools of light to create distance in the covered Paris market. And on the oil rig, we had 2200 mercury and sodium vapor lights.”

Of all the sets, the only one that wasn’t “carified” was a massive oil rig set in the North Atlantic. “John said it was already ‘carified,’ ” Jessup says. “It’s creating their food.”


At left, Pixar TDs incorporated Tessendorf algorithms into an ocean system created for Finding Nemo to produce the kind of stormy, non-breaking waves Lasseter wanted. At right, layout artists fastened Finn McMissile, and the boat in the image at left, to the waves using a system that included offsets for believable bobbing.

As with the other sets, the crew first roughed in basic architecture quickly to tell the story. “We knew where Finn McMissile needed to jump onto the oil rig and what vantage point he needed once there,” Halstead says. “And we had to work out a path for the important chase scene. But once we had a core structure, we could go back in and make use of a building-block approach for the girders and truss work.”

Oceans of Development

The oil rig appears in the opening sequence, a James Bond-ish sequence that starts in the open ocean. “The first thing the film does is surprise people,” Calahan says. “We have an ocean in the black of night, with lights from the oil platform reflecting into the water. John was excited about the water technology.”

The sequence became the most challenging for the effects team. “During pre-production, we were getting ready for all things cars,” says Gary Bruins, effects supervisor. “Dust, peel-out tire marks ... everything anyone would expect for a Cars film. And then we got word of a new sequence. The verbal description was ‘large ocean swells, stormy, but the waves don’t crash.’ ”

Once Bruins met with Lasseter and understood more about the look and feel the director wanted, he tried using the ocean-wave system developed at Pixar for Finding Nemo. It didn’t quite do the job.

“Two things were missing,” Bruins says. “The first was that ocean waves are typically made by accumulating many sine waves at different frequencies and amplitudes. This accumulation gives you the big-body look. But in the Nemo system, the users had to add those sine waves manually. For calm waters, that was easy. For this film, it was a big chore. We had to keep adding and adding sine waves, and every time we added a new wave, we had to specify the frequency and wavelength.” The other element missing from the Nemo system was horizontal displacement. However, the Nemo system had one important quality the team didn’t want to lose: production friendliness.

After considering various tools, plug-ins, and third-party solutions, the team decided to implement a well known and highly regarded system developed by Jerry Tessendorf, a principal graphics scientist at Rhythm & Hues. Tessendorf, who had taught courses at SIGGRAPH on simulating ocean water in 2001 and again in 2004, received a technical achievement award for creating the fluid-simulation tools from the Academy of Motion Pictures Arts and Sciences in 2008. “We asked Alexis Angelidis, one of our technical directors, to shoehorn Jerry’s approach into our system,” Bruins says. “Before he implemented a single line of code, he spent time making sure he understood the algorithm and technique backward and forward. He dissected it using [Wolfram’s] Mathematica and by doing experiments.”

Eventually, Angelidis replaced the library of code that produced the waves in the Nemo system with the new technique from Tessendorf’s system. “Once he had implemented Jerry’s approach as a library, we just redirected the larger Nemo system to look at that library instead,” Bruins says.

Early tests with the hybrid system produced the look the team wanted to see, but Angelidis took the system even further. “He found a way to add wavelength features,” Bruins says. “We have the user supply a minimum and maximum wavelength and then, for a given ocean shot composed with three to six wave models, we could have low-frequency waves with directionality, mid-frequency waves with less directionality, and on top, high-frequency waves with less height—all by setting parameters.”

This, Bruins points out, provided the art-direction the flexibility they wanted as they composed the waves within a simulation. “Let’s say we have a wave system with large, low-frequency swells,” he says. “We could add another system, like adding displacements upon displacements, accumulating them until we get a final result.”

Angelidis also implemented horizontal displacement from Tessendorf’s papers to create a stormier-looking ocean. “By default, the waves had rounded peaks, which look good, but we wanted stormy waves with sharper peaks,” Bruins says. “However, when you increase sharpness or horizontal displacement, the waves push through themselves; if you tone down the horizontal displacement, you lose the choppiness.”

So, by analyzing the wave system, Angelidis found a way to solve the problem procedurally. “He detected the amount of displacement, and then toned it down in the areas of penetration,” Bruins says. “With a slider, we could set percentages to find the right balance.” And, the team could compute the waves as needed on the fly: Angelidis had optimized the code well enough to avoid having to bake out the waves for rendering.

For the layout artists, the effects team provided a generic water model that came with settings they could use to construct waves. “They could choose the library settings they wanted, and if they couldn’t get the look they wanted, we provided new settings,” Bruins says. “Usually, they dealt with proxies. They could have a rough approximation of the whole ocean and then move a small patch with all the detail of a wave, like moving a magnifying glass across a map.” The artists then constrained boats, which are also characters, to the ocean model using a system that included offsets to create believable bobbing, and sent the blocked-in boats on to animation.

Once the animators finished polishing the boats’ performances, the waves rolled back to the effects department. “One of the downsides of Jerry Tessendorf’s approach is that the waves are on a fixed grid, and beyond this fixed area, they repeat and tile,” Bruins says. “So we disguised or removed the noticeable tiling by creating a duplicate, say 200 frames or so, and mixed in a 2D noise pattern.”

For boat interaction with water, the artists used an event-driven system built within Side Effects Software’s Houdini. “An artist would bring in a boat and bring in the waves,” Bruins says. “The system would detect the relative velocity of the boat to the ocean waves and decide whether to emit spray from the boat’s interaction with the water. The amount of spray depended on the boat’s speed through the water. The faster the boat goes, the larger the velocity of spray generated from the boat.”

Although the department created other effects—the expected skid marks, smoke, and dust, from the speeding cars, and bullet hits and explosions from the spy action—the ocean was the most significant effort. “The bulk of our energy was spent on the ocean sequence,” Bruins says. “I felt like a lot of our contributions took place in that sequence.”

Road Trip

One of the biggest breakthroughs, though, was perhaps the smallest. “We had to find creative solutions for John’s time,” Calahan says. In addition to directing this film, Lasseter is chief creative officer at Pixar and Walt Disney Animation Studios, and principal creative adviser for Walt Disney Imagineering. As such, he was executive producer on several other films in the works while Cars 2 was in production, including Toy Story 3 and Tangled.

“Thank God for Steve Jobs, who introduced the iPad a year ago,” Lasseter says. Lasseter began looking at stills and shots on his iPad during the two hours he spent each day commuting to and from his home in Sonoma County and Pixar in Emeryville, California. “I was recording voice memos on my iPhone,” he says. “And then Apurva [Shah] wrote an iPad app, a review tool for me. Now, I have two to four iPads loaded with stills and video. I have great video control. I can record my notes verbally, push a button, and the iPad e-mails them to the right people.”

The only part of the process for which Lasseter felt he needed to be in a room with people was for story development. Otherwise, the iPad reviews worked for all the departments: lighting, animation, effects, set design, layout, and so forth. “It worked for art,” Jessup says. “The excitement John has comes through. In the morning, you hear his voice coming out of people’s offices. It’s much better than waiting in a room for him.”

The concentrated commute time worked better for Lasseter, too. “One hour on the iPad equaled three hours in the studio,” he says. “I kept in touch with everyone. I did reviews in the car. My assistant now books my drive time.”

Lasseter stops to think for a minute and then says, “I did Cars 2 in a car.”

For a film in which everything, from text on billboards to the “cargoyles” on a church, is part of an automobile world, that’s as it should be.

“John loves the world of Cars,” says supervising animator Dave Mullins. “He brings us along for the ride, and he always delivers.”

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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