The new movie Big Hero 6 represents the first-ever partnership between Marvel and Disney, two entities known for constructing fantastical universes. So it's not surprising that bringing the story to film also required building an entire city of the future: a blend of Tokyo and San Francisco named San Fransokyo.


When encouraged to develop a Disney film that drew from Marvel's universe (which Disney purchased in 2009) directors Don Hall and Chris Williams dove deep into the Marvel archives, selecting an obscure comic—"Perhaps the most obscure Marvel comic," quips Hall—about 14-year-old robotics whiz Hiro Himada and his puffy sidekick, a compassionate caregiving robot named Baymax.

The original comic took place in Tokyo, but to make it their own, Hall and Williams decided to set the story in a brand new yet familiar city, melding the original locale with a near-future San Francisco. "It's a very high-tech city that blends Eastern and Western culture, so we wanted it to be a mashup, just like the movie is a mashup between Disney and Marvel," says Hall.


The resulting animated metropolis—which truly is its own character in the film, although people say that a lot—is a celebration of futuristic urban life and the high-tech culture that drives its residents. And it's brought to life thanks to several new animation technologies developed in-house by Disney itself.

A two metropolis mashup

Geographically, San Fransokyo is San Francisco. In fact, it's pretty much an exact representation: The animators used detailed property data from the city's Assessor-Recorder's office—available thanks to the city's progressive open data program—to get detailed information about the city's 83,000 buildings and the nearly exact number and location of elements like streetlights and street trees. "We don't claim you can find your house" says Big Hero 6's technical supervisor Hank Driskill. "But if you go to where your house is, you'll find the right building of the right size."

The visual effects team recreated 23 separate districts, each of which has its own hybridized Pacific Rim architectural style. Even though the overall result immediately registers as San Francisco, the specific details in the streetscape are less recognizable. Almost all the signage is in Japanese (and there's a lot of advertising). Even the Golden Gate Bridge has its own Tokyo twist.


The filmmakers took some dramatic license with the city's geography, of course. The famously steep hills are twice as high, for example, turning the streets into rollercoaster-esque cable car routes. And the skyscrapers are twice as tall, too. Many neighborhoods still incorporate the city's iconic Victorians, but the Financial District, for example, is far more Shibuya than San Francisco.


In previous Disney films, the city in the background would likely have been a matte painting, the details purposely vague and predetermined by storyboarding. Here, the level of accuracy in this digital model allows a completely new way for the directors to pick their shots and center the action. What Disney's dubbed "digital scouting" gives the filmmakers an almost completely generated universe to use for camera capture. "You're not just building the set that you need, you can put the camera anywhere and something would be there," says Williams.

The effect is dramatic, and unlike anything you've seen in an animated film before. In one key scene for the film, Hiro and Baymax are flying over the highly stylized city, zooming over the Bay and weaving between the sparkling skyscrapers. You can see satellite dishes on rooftops, and clearly read the posters plastered to the side of buildings. Look closely: The filmmakers say there are more Easter eggs in this film than any other Disney movie.


Lighting and populating the city


Every animation project for Disney is city-building, essentially, says Disney Animation Studios CTO Andy Hendrickson. "Our job is to build a compelling world that you want to live in that supports that story." But Big Hero 6 required a whole different level of complexity: There are more objects in the film than in the last three Disney animated films, combined. "How do you go about handling that level of geometry? How do you light it?"

Disney employed brand-new technologies to solve these issues: Hyperion, which would help them naturally illuminate the urban landscape and accentuate the detailed angles of the structures they'd built; and Denizen, a character-generating system that populated the city with hundreds of thousands of realistic residents.

Accurate lighting is a challenge for any animated feature, but especially when creating a city, where light reflects off billions of shiny surfaces in any given shot. Hyperion is a new rendering technique that uses global illumination to reorganize these rays and bundle them in a way that allows the light to bounce around more naturally. It algorithmically imbues every shot with real-world lighting, which can then be tweaked by the filmmakers in a composite system.


It also required Disney to build new supercomputers just to manage the renders that Hyperion was generating, jobs that would sometimes take weeks. So Disney built a brand new render farm that could handle up to a million renders a night—a system so big that it had to be geographically located in four different places, with three farms in LA and one in San Francisco.


The next task was populating San Fransokyo. "Early on, when we started talking about the movie, it wasn't just that we wanted to make a city, we wanted it to feel like an urban environment," says Driskill. When Disney had worked to create cities before, as in the movie Bolt, filmmakers were limited in their ability to create the hundreds of people needed for a busy street scene. "We crafted the New York City scenes to try to aim cameras just so to create the illusion that it was New York City, but we couldn't really reproduce New York City," he says.

Using Denizen, which was created by character rigging supervisor John Kahwaty, the team could rapidly generate a wide variety of characters who fit the style of the film (including avatars of all the crew). The filmmakers created 750,000 people total, about the actual population of San Francisco. Just in the opening shot alone, there are 6,000 crowd characters—each of them completely unique.


Building the future


Creating a San Francisco-Tokyo mashup also allowed the filmmakers to blend the cultures of two likeminded cities which are serving as incubators for real-world technological solutions, like the film's caregiving robot. "San Francisco is the home of Silicon Valley, it's the hub of technology, and Tokyo is like that, too," says Hall. From a scene at a university science fair that could have been filmed on the Google campus, to the fact that the main characters all have 3D printers in their home studios, Big Hero 6 shines a light on these cities of makers and hackers.

In fact, it was very important to Hall and Wiliams that all the technology featured in the film was real—or at least rooted in reality. The filmmakers toured robotics labs at MIT and Carnegie Mellon looking for specific projects that might be entering the consumer world in five to ten years. "It has to be grounded in a believable world, and that led to all the cool technology that the team in the movie has," says Hall. In this way, it might be the first Disney movie built around science, not, say, magic. "The movie does celebrate science and technology in a way that we really haven't done before."

Yet the futuristic tech couldn't outshine the film's star: The inflatable Baymax still had to be the most amazing technological advancement found in San Fransokyo. "The big question for us was how should people react to him?" says Williams. "He was amazing enough that people would be mouth agape, drop what they're holding. But it's a society that's a little more advanced than ours in the sense that seeing a robot walking down the street isn't quite as far-fetched as it would be in our world."


Deciding on that benchmark for technology in San Fransokyo's society also drove specific urban planning decisions. There are no flying cars here; instead, there are new elevated freeways filled with vehicles (which are not autonomous yet; traffic is apparently still a problem). The cable cars are still there, although there are many more of them, in a variety of styles, and also a kind of elevated BART that laces through the downtown. Yet in one of the most beautiful and aspirational tech details for the city, colorful airborne wind turbines spin high above the towers, generating clean energy for the residents below. "To me, that's a very hopeful technology," says Hall.

We so rarely get to see a San Francisco of the future (maybe the new Star Trek is a good example?), and this peek of a pan-Pacific mashup is probably the most accurate depiction of the way the city is already evolving. Like the film Her helped envision a denser Los Angeles, Big Hero 6 celebrates San Francisco's high-tech culture while nudging it gently towards one possible future for a taller, faster, flashier city. From my seat in the theater, it was a pretty beautiful vision.


All images courtesy of Disney