Sun goes Hollywood 117 SPARCstations render "Toy Story," the first feature-length computer-animated film By Jeff Ubois

November  1995

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This fall, the most ambitious collaboration between Hollywood and Silicon Valley to date will hit the screens in the world's first feature-length computer-animated film, "Toy Story."

Marketed and financed by Disney, "Toy Story" (see the sidebar for a plot synopsis) was written, produced, and directed by Pixar Animation Studios in Point Richmond, Calif., formerly a unit of LucasFilm, and now 75 percent owned by Apple co-founder Steve Jobs, who is also the film's executive producer.

Pixar is best known by many in the graphics community for its RenderMan ToolKit, used to create the dinosaurs in "Jurassic Park" and the liquid metal cyborg in "Terminator 2," and its Typestry software package (see Pixar's RenderMan and Typestry sidebar). But the company has also won numerous Academy Awards and Clio Awards for its short films and commercials.

With "Toy Story," the company began an odyssey into territory owned by Hollywood. "There are two ways to look at the film: one is that it is the culmination of 20 years of research that have brought us to this point," said Pixar founder and chief technical officer Ed Catmull. "The other is that this is a whole new way of making feature animated films, and with this technology we are at the start of a long period of improved productivity and quality."

"Toy Story" is also something of a coup for Sun Microsystems. The movie's final image rendering was accomplished on a "farm" of 87 dual-processor and 30 quad-processor 100-MHz SPARCstation 20s -- representing more computing power than 300 Cray 1's. "There is more computer power applied to this film than [to] any film in history," Catmull said.

Even with that, rendering the film's 110,000 frames required the equivalent of 46 days of continuous processing; put another way, rendering each frame took one to three hours of SPARC processor time. "We could use 1,000 times more power, and we know exactly how we'd use it -- we're limited by the budget, not our appetite," Catmull said. "It's not like someone who is doing a spreadsheet and wants two or three times more power for faster turnaround but isn't going to do anything fundamentally different."

Why Sun?
Silicon Graphics has the dominant mind share among animators, film, and video producers, and has some important graphics software tools not yet ported to other platforms. For "Toy Story," SGIs were used to handle modeling, animation, shading, and lighting. But SPARCstation 20s offered a clear price/performance win.

Using data from a series of typical pictures, Pixar developed its own benchmark, called a rendermark, to measure the rendering performance of different hardware running Pixar's RenderMan software. "We evaluated the different platforms on the list price per rendermark, and Sun was less expensive than anybody else by almost a factor of two," Catmull said.

"Sun was very smart in its pricing of multiprocessor technology -- most companies make you pay a premium for it, so there's no saving from sharing power supplies and other common elements," Catmull said. "Sun's four-processor versions are much cheaper per processor."

The SPARCstations also had a size advantage. "The SPARCstation 20s with four processors are lot cheaper and in a small package, so you've got more processing per cubic foot, which is an odd way to measure it, but it turns out to be important," Catmull said.

In a sense, Pixar has come full circle. Back in the LucasFilm days, what is now Pixar wrote the first operating system Sun used. "The very first Suns that were delivered ran a version of Unix that we wrote for them, and for the first year of Sun's existence, this group was their largest customer," Catmull recalls.

Down on the CPU farm
The farm itself is essentially a wall with 117 SPARCstations configured as headless servers, each with 192 to 384 megabytes of RAM (each processor has an average of 96 megabytes of RAM) and three to five gigabytes of local disk storage. The local disks hold a copy of Solaris, some proprietary job control software, and Pixar's RenderMan. "There has to be a huge swap space, and space to download models," said David Ching, Pixar's manager of computer operations.

Jobs are fed to each SPARCstation from a SPARCserver 1000e, which contains the basic information -- models, textures, shaders -- needed to complete the rendering of the frame. Pixar's propriety job control software feeds the frames one at a time to each workstation, and ensures an even distribution of work.

The SPARCstations are connected to the server though Grand Junction hubs, which connect to 24 of the SPARCstations via 10BaseT, and to the SPARCserver 1000e via a 100 megabyte 100BaseT link. The SPARCserver 1000e is connected to the rest of the company's network, comprised mostly of SGIs, via 10BaseT, and via FDDI to SGI Challenges and Indigo 2s that act as master servers. The master servers store models of different objects, these are retrieved as needed by the SPARCserver 1000e.

"Essentially the SPARCstations, when they need to refer to a model, get it from the 1000e, which gets the model from the master servers," Ching said. Pixar calls its collection of modelling data its "digital back lot."

Shifting around the terabytes of data generated during the course of production is enough to stress any network. To improve performance, Pixar initially considered placing each SPARCstation on its own Ethernet segment, and other more exotic high speed technologies, but economic considerations ruled those choices out.

Ching said the company is now looking to go to 100BaseT connections throughout. "HIPPI and FibreChannel are too expensive -- we really didn't want to look at having to pay for more than 100 high-speed interfaces," Ching said. "Of course, if we had had gobs of money, we would have done fiber or 100BaseT, but back in January, that wasn't economical."

Pixar has two large disk farms, an SGI Challenge with 144 gigabytes, and a Sun array of 108 gigabytes. Both together aren't enough to hold an entire movie, so images that have been "finalled" (received final approval from the director) are recorded onto film and backed up to an 8mm Exabyte tape drive.

But because the rendered data is essentially generated on the Suns, working data is not backed up. "We only back up important data that can't be replaced; the rest can always be re-rendered," Ching said. "We had one power outage that cost us some data, but the truth is the data was replaced within a day."

For the future, Pixar is planning a number of improvements. "We're looking at automated cartridge back-up systems that can handle 100 gigs of data very quickly," Ching said. "We'd also like to know more about ATM, we'd like to have switching hubs and maybe a video server."

ATM and the switching hubs will be used to improve network performance, while the video server will speed movie production more directly by letting animators do their work more interactively and efficiently. Rather than having to wait and view their work in a special light room, the video server will allow them to view clips right at their desks.

Plot line and subject matter aside, "Toy Story" marks a departure into a brand new world of movie making. With the computer industry eager for new business, the studios desire to cut costs (and those annoying percentages out of the gross now going to top actors), and with Steve Jobs' arrival on the Hollywood scene, graphics geeks can rest assured that world domination is only a matter of time.

Resources

• Pixar's home page
  http://www.pixar.com/
• Disney's "Toy Story" home page
  http://www.toystory.com/

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Positioned as Disney's Christmas mega-movie, "Toy Story" is a comedy/adventure in which toys take on a life of their own when no one is watching.

"Toy Story" features the voices of Tom Hanks as Woody, a pull-string talking cowboy doll, and Tim Allen as Buzz Lightyear, a superhero space action figure. The two learn to put aside their rivalry and work together when they become separated from their owner, a boy named Andy.

These and other characters will be reincarnated in an interactive CD being produced by Pixar, in numerous licensing deals for toys, and a joint marketing campaign with Burger King arranged by Disney. Other well known toys, from Mr. Potato Head (with the voice of Don Rickles) to Slinky Dog (with the voice of Jim Varney), also make appearances.

Four years in the making, "Toy Story" is directed by John Lasseter, who also directed Pixar's "Tin Toy," a seminal computer animation short made in 1988 about living toys. "Tin Toy" was the first computer animated film to win an Academy Award, and "Toy Story" is very much a descendent of that film, many doublings of computer power later.

Editor's note: In October 1996, the editors received the following message from Joy Gipson (joy@pixar.com), marketing communications manager at Pixar: We no longer sell or support Pixar Typestry as referenced in your Web site.

In addition to movies, Pixar also sells two software packages, RenderMan and Typestry.

RenderMan runs on Sun, Silicon Graphics, Macintosh, and other computers, and produces photo-realistic 3-D images in TIFF, PICT, EPS or TGA formats from mathematical models for shapes, shading, texture, and lighting. Like a digital camera that controls focus, exposure, viewing angle, level of detail, RenderMan computes the final image.

Partly because it has been on the market since the late 1980s, and partly because it runs on so many platforms, a raft of third-party RenderMan-compatible programs are available. In fact, for any real production, third-party products are necessary, because RenderMan doesn't do modeling or animation.

Among RenderMan's credits are the dinosaurs in Jurassic Park, the cyborg in Terminator 2, the water creatures in The Abyss, and images in Tin Toy, Free Willy, Cliffhanger, and Casper.

Pixar's Typestry lets users create three-dimensional type, and manipulate it in a variety of ways, wrapping text around a sphere or tube, or onto a rubber sheet. It also supports animation, changes the appearance of type surfaces, and even handles particle emissions from type surfaces.