Millimeter article

Tippett Studio rendered the animal characters for Cats and Dogs (no penguins) with a Linux version of Pixar's RenderMan, which has run on the free OS for some time.

At this summer's annual SIGGRAPH computer-graphics fest in Los Angeles, attendees likely saw more than a few cartoon penguins because this year, more CG software than ever will be demonstrated on computers running the OS symbolized by a little penguin mascot — Linux. The freely downloadable Linux OS, a PC variant of the venerable Unix operating system that runs on pricey workstations, is a growing force in the business of digital production.

An obvious sign of Linux' waddle to prominence is that several programs popular with professional users featured Linux versions at SIGGRAPH, including high-end 3D animation packages like Alias/Wavefront's Maya, Side Effects' Houdini, Avid's Softimage XSI, and Kaydara's Filmbox, along with 2D compositing tools like Silicon Grail's Rayz and Nothing Real's Shake. A Linux version of Pixar's pre-eminent rendering package RenderMan, which has been ported to Linux for a while, was also on display.

Click here for more information on Linux at SIGGRAPH

A key reason for this development can be summed up in two words: customer demand. When prominent digital production experts held a summit last year at the Visual Effects Society, they voiced an unequivocal desire for Linux-based tools. Realizing that cost-effective PCs were replacing Unix-based workstations, the effects experts stressed a need for professional-grade software that would run on networked PCs. They wanted the stability that they had enjoyed with Unix and felt wasn't offered by Microsoft's Windows. They wanted Linux. (See “The Little Engine That Could” in the February 2001 issue of Millimeter.

The Early Adopters

Software developers were listening. At Alias/Wavefront, Chris Ford, senior product manager, says, “A primary motivator for porting Maya to Linux was the Visual Effects Society initiative. Clearly those are very influential folks in the high end of our business, and it's important for us to keep faith with them.” This move is especially significant because Alias/Wavefront is owned by SGI, whose IRIX version of Unix has been the dominant operating system in digital studios for years. Ford acknowledges that, “because of uncertainties over the future of IRIX, high-end users want to have a Unix-like environment on which to base their pipeline. They have requirements for very large-scale networking and control of huge jobs, and clearly Unix-based systems handle those tasks very effectively. Linux was an obvious alternative. To maintain our presence in the high-end animation business, we must have a viable Linux offering for those users. The games industry has also been purchasing Maya on Linux, which has been shipping since March.”

“[This version] is functionally the same as any other copy of Maya,” Ford says. “We actually stepped into Linux in two stages. We made Maya's back renderer available on Linux about a half-year ago, and that experience was a contributing factor in deciding to port the whole interactive application to Linux.”

The rendering part of production is where Linux-based applications established their first foothold, with good reason. “The render farm is just a computer server environment and doesn't require anything like fancy graphics cards,” says Dana Batali, Pixar's director of RenderMan product development. “It just requires a good stable network configuration. We've had a Linux offering since PRMan 3.8, which goes back a couple of years now.”

The more difficult problem has been bringing Linux to the front end of the production process. Batali notes, “The hump that you have to get over is getting artists' stations configured with the right graphics cards. It's been a painful process. You basically have to be a Linux guru to get a solid, 3D Open GL accelerated graphics environment running.”

That reality was very much on the mind of Side Effects CTO Paul Salvini when he began porting Houdini 3D animation software to Linux in January 1999. “At that time, there wasn't much accelerated 3D graphics hardware support, largely because there were no 3D applications running on Linux. The people who'd be providing hardware support said, ‘There's no point, because there are no applications,’ and the people who write the applications said, ‘We can't port our applications if there's no support.’ It was a chicken-and-egg problem. Something had to move, and we decided to take that first step.”

“We had cheers in our user group when we made the announcement,” Salvini says. But the task, he admits, “was very difficult. Every time we'd get close, we would need some piece of 3D technology that just wasn't there. We had joked that we'd port Houdini to Linux on a weekend, and two of us did actually come in one weekend and gave it our college try. We failed miserably! In the end, it took us about five weeks, and it was at least a year before we had Houdini running in a state that was suitable for production use.”

Salvini credits Hewlett Packard for “being the leader to come out with a box that ran Linux and was fully accelerated so you didn't have to cobble pieces together from various manufacturers. It's one thing to say that your product runs on Linux, but so what if you save $200 on the OS and you need a $5,000 graphics card?”

Side Effects unveiled Houdini for Linux at SIGGRAPH ‘99, and after two years, Salvini says, “The vision of running it on Linux with a cheap, off-the-shelf graphics card is finally here. I recently saw Houdini running with a $200 graphics card in a stock box and having the performance that an animator would want.”

The Rising Tide

The Linux movement gained greater traction in the world of high-end digital production as other parts of the pipeline began being served by Linux-based tools. By April 2000, software developer Nothing Real had ported its Shake compositing program to Linux. “We'd had informal ports in-house for over 2 years,” recalls Jean Luc Bouchard, Nothing Real marketing director, “so we were quite familiar with Linux. Our port actually could have been ready earlier than April, but we couldn't show it because there were no graphics drivers.” Bouchard believes that only two manufacturers have done a good job. He says, “We gave HP a laundry list of what we needed, and they came right back to us. [Graphics card manufacturer Nvidia] slowly followed.” (For Bouchard's first-person account of Nothing Real's experience, see “The Lure Of Linux” in the February 2001 issue of Millimeter.)

Production houses actually have a choice of Linux-based compositing applications, with Silicon Grail offering its latest interactive tool, Rayz. Company founder Ray Feeney notes that Silicon Grail's earlier compositor, Chalice, which runs on IRIX and Windows NT, will not be ported to Linux. “We decided we would take care of our Chalice customers with more extreme technology. We'll slingshot them forward rather than offer both our products on Linux and give our installed base a compelling reason to move to new technology.”

It is hardly trivial for developers to port complex software to Linux, observes Feeney, “because the media libraries don't exist. With IRIX, SGI had lots of libraries for digital media that don't exist for Linux. So to be successful with a Linux application, you have to do much more in the way of interactive stuff yourself. It has to be built into your application.”

Although Linux may offer some of the advantages of Unix, Bouchard notes, “It's not IRIX. SGI has written a lot of custom tools over the years that facilities have depended on and thought were part of Unix. Those tools were really part of SGI's IRIX version. There are equivalents in the Linux world — you just have to find them.”

Continued momentum for Linux will depend upon bridging the gaps in the tool set. As Feeney says, “Right now, there really isn't a procedural paint system to do stuff like wire removal.” And the closest Linux stand-in for the perennial touch-up painting tool Adobe Photoshop is a public domain program called GIMP. Feeney says, “What production companies have been doing over the last year is deciding which applications are key, and if a Linux version doesn't exist, figuring out if they can bite off the task of writing it themselves or compelling someone else to do it.”

Agreeing, Salvini says, “Getting a critical mass of applications is an issue. Assuming that Linux continues to grow at its present rate, there will be pressure on vendors to provide Linux versions of their products within the year.”

Indeed, the need to remain competitive has recently prompted Softimage to port a version of its XSI software to Linux, which it previewed at SIGGRAPH this year. Alan Waxenberg, Softimage business development director says, “We're porting to Linux because of customer demand. We're expecting to release XSI and Softimage 3D running on Linux this fall. Whether or not it grows, it's too early to say. We're in the pioneering stages of the implementation of Linux in real production. It's going to be a while before everybody's in the comfort zone to risk whatever expendable resources they have for moving into the Linux culture.”

The Question of Standards

The word “culture” really does apply to Linux, which is a product of the open-source movement, with countless thousands of people working to improve it. Multiple flavors of Linux can be freely downloaded from servers around the world, which presents software developers with different challenges than they've had porting their software to operating systems controlled by Microsoft or SGI.

“It's hard to work with something that doesn't have a single version,” says Salvini. “It's definitely a moving target, a constantly evolving product coming from many different sources with different bugs and patches. That's going to be a challenge for Linux over the next few years.”

Further, Bouchard warns, “There are some exotic flavors of Linux that you don't want to touch because they change every two weeks.”

The flavor of the Linux OS that's emerging as the standard to which high-end applications are ported is Red Hat, which can be purchased or downloaded for free. RenderMan, Maya, Shake, Rayz, and Houdini are certified to work on this version of Linux, and Salvini believes that “at least half of our customers run Houdini on Red Hat. But there's no reason why our software wouldn't work on other Linux distributions as long as they're fairly up-to-date.” Softimage, in fact, plans to go with multiple distributions of Linux, according to Waxenberg. “We intend to support as many Linux distributions as we can, as long as those Linux companies have the infrastructure to support their distributions, which pretty much narrows it to Red Hat and SuSI a couple of other players.”

Batali asserts, “It's become a nontrivial maintenance issue to make sure that the tools that are being built run on all the different flavors of Linux. I don't see any short-term remedy to that battle.”

For the Linux version of Maya, says Ford, “We've limited the number of versions of Linux that we support. I'm often asked ‘Will Maya run on X-odd version of Linux,’ and the answer is often yes. But can we guarantee that if some error pops up, we'll be able to diagnose it? The answer is no because it's difficult to nail down whether the problem is the operating system or our application. To maintain a viable product, we have to have a fixed reference point, which is why we've consolidated on Red Hat.”

So developers are betting that the newly profitable Red Hat will continue to thrive. At Batali says that, at Pixar, “When we install a new version of Red Hat, we pay the $39 for the CD rather than just downloading it to make sure that some cash flows in their direction.”

The Road Ahead

The desire by production companies to have low-cost, networked computers seems likely to fuel the continued growth of Linux. Waxenberg says, “The cost of doing business today is based on a global economy, not a regional one.” Citing the rise of production in India and Australia, he adds, “Costs are driving companies to look for other measures to be productive.”

Salvini also notes that “outside the US, where the cost of operating systems can be considerable, Linux has great appeal. In Japan, and places where there is strong digital media like India, we see great interest in Linux.”

It's difficult for developers to track the percentage of customers who are already running their software on Linux machines because most offer licenses that users can float among several operating systems. For RenderMan, Batali reports, “We're seeing fairly similar growth curves for Windows NT and Linux.” At Softimage, Waxenberg says, “We have an expectation that 12% to 15% of the market will be Linux.”

What seems certain, says Feeney, “is that most of the high end people are not scared of Linux, even though it requires a professional team to support it. Since IRIX is going away, I would expect that over the next three years, the installed base will be Linux.”