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Pacific Data Images (PDI), the animation co-production arm of DreamWorks SKG, is best known for its cutting-edge animated films "Shrek" and "Antz," and it pioneered computer-assisted animation and 3D rendering using high-powered SGI servers and workstations. But as the hardware began to show signs of age, PDI/DreamWorks Animation looked for a better platform, according to Scott Chapin, with DreamWorks animation technical support.

The company needed a system that was reliable, scalable, and capable of high performance on the desktop -- and system that was cost-effective to maintain and used commodity, Intel-based hardware. This new platform would replace not only the the back-end "render farm" of servers, but also the desktop workstations of the artists. After evaluating a wide range of solutions, including Windows 2000 and Mac OSX (which was still in beta at the time), PDI/DreamWorks Animation settled on Linux on Hewlett-Packard graphics workstations. (More on the HP connection in the sidebar below.)

"When we evaluated potential systems, Linux presented its own set of problems. It was not quite ready for our desktop environment," Chapin says. But, he continues, "efforts from HP and Red Hat met those needs."

PDI/DreamWorks Animation replaced its entire "render farm" with x86-based servers running Linux. For "Spirit," the company created a Linux cluster for back-end rendering. Over the months, the cluster has grown to its current size of about 500 CPUs. These servers handle the nitty-gritty work involved in creating what PDI/DreamWorks Animation calls "tradigital animation" -- the blending of 2D and 3D animation. DreamWorks says tradigital animation combines the best of two worlds, leveraging the visual power of 3D animation, but at the same time preserving the tradition and art of 2D animation.

Under the previous architecture, generating the 3D graphics was such an intense process that it took more than three hours to render a single tradigital scene, costing animators serious time even when only small changes were made. The switch to Linux, though, offered big returns as rendering was cut from three hours down to nearly real time. This improvement in speed gave artists the opportunity to focus on their art, not the process of generating it.

Servers were only one piece of the puzzle, as PDI/DreamWorks also migrated all of its workstations to Linux as well. Using Linux as a desktop environment for artists was a challenge. Initial problems arose with the X server. At the time, XFree86 did not meet the performance needs of DreamWorks artists. HP offered to port its own X server to Linux to serve as an interim solution -- a decision that just may have been the deciding factor for DreamWorks, Chapin says. As the XFree86 project ironed out a few wrinkles, PDI/DreamWorks migrated back from HP's X server to XFree86. HP and Red Hat have continued to offer support services to DreamWorks, tackling problems ranging from efficient installation of new workstations to kernel timing issues.

With desktop performance and stability achieved, PDI/DreamWorks Animation began working on applications. DreamWorks uses a wide array of tools for the production of films, ranging from unadorned and straightforward drawing programs developed internally to Alias|Wavefront's wildly popular Maya 2D/3D modeling engine. The transition to Linux required that PDI/DreamWorks Animation port all of its own tools from SGI. At the recent National Association of Broadcasters' show in Las Vegas, Chapin demonstrated the Linux version of PDI's 2D sketching program, an animation tool, and a piece of hardware called ToonShooter. ToonShooter has a camera precariously mounted a couple of feet above a drawing board. Artists first sketch on paper, and then slide the paper through ToonShooter, where the image is digitized and animated on the fly. From that point, the artists can easily work with those same images on their workstations and quickly integrate those images into existing scenes, saving many animators many hours of work.

Sequences of drawings can be rapidly captured and stored, preserving the transition of animation from paper to pixels. Ultimately, ToonShooter is a means for PDI/DreamWorks to meet its goal of "conserving trees" while providing artists with a better way of creating animated scenes, Chapin says.

Third-party tools presented a bigger porting challenge. Few of the high-end commercial graphics tools supported Linux out of the box. Together, HP and PDI/DreamWorks worked to convince Alias|Wavefront and others that they needed to port their applications to Linux. Ultimately, HP and PDI/DreamWorks Animation were successful, and DreamWorks has fully integrated Linux versions of all of its major tools including Maya and Wacom's Cintiq interactive pen display.

DreamWorks is quick to point out that, in the words of one DreamWorks representative, "We are not Linux zealots. DreamWorks just wants to tell the story." For the company, Linux and an Open Source platform provided the best way for them to accomplish their aims.

Chapin relayed a cheerful account of the cooperative nature of the Open Source community, pointing out the work of HP, Red Hat, and many other hackers who provided, improved, and maintained the tools that ultimately enabled DreamWorks to transition to an almost 100% Linux shop. "And when we can," he says, "we try to feed our kernel and video changes back into the community."

DreamWorks seems to understand the concept of community embodied in the Open Source movement. The company saw that its needs for reliability, performance, and scalability were met. DreamWorks also recognized that the areas where Linux didn't meet its needs could be overcome because the source was available and the vendors were willing to help. The release of "Spirit" will represent a success for both DreamWorks and the Open Source community, which proved the viability of the Open Source model to an industry that has been dominated by proprietary and closed-source products.

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The HP/DreamWorks connection

In January, DreamWorks and Hewlett-Packard signed an agreement to collaborate on several animation initiatives, says Mike Balma, Linux solutions strategist for the HP Linux Business Development Organization.

That agreement has resulted in the centerpiece of the increased Linux presence in the making of "Spirit," the HP workstation x4000 running Linux. "Linux came up as an opportunity for [DreamWorks] to have relatively a seamless port from IRIX," says Jeff Wood, product marketing manager for personal workstations in the HP Technical Computing Division.

HP's tech staff, which has experience with the company's own seven generations of graphics solutions, also helped DreamWorks get 3D acceleration in Linux from an unimpressive three frames per second rendering speed up to a speedy 46 frames per second, Wood says. HP and DreamWorks also worked together to create accelerated 3D on two Linux screens at the same time, he adds.

DreamWorks is now running about 600 workstations on Linux, using HP's proprietary graphics hardware, Wood says.

Two other studios are now starting to deploy x4000 workstations for animation, Wood adds. Look for HP announcements soon.

Balma says HP and DreamWorks are also working together on some futuristic technology initiatives, such as movie-making packages for consumers. Those projects may or may not be based on Linux.

-- by Grant Gross

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