Linux Powers The Spiderwick Chronicles

As Creature Supervisor for The Spiderwick Chronicles, visual effects pioneer Phil Tippett oversaw the design and development of the film's fantasy characters. “Phil Tippett was on set with me every day”, says Director Mark Waters. “We were working on Charlotte's Web when Mark Canton gave us the script”, says Tippett Studio Visual Effects Supervisor Joel Friesch. “When we saw the creatures, we had to do it. It's based on real creatures, not fantasy. We wanted Hogsqueal. We created a bull goblin marquette [a detailed statuette] that gave Mark something he could hold. The bull goblin is based on toads. We brought in real toads and photographed them. We created movies good for the animators, showing how the eyes move and the throat. We created a test scene with a goblin scratching the back of his leg. That took one month of modeling and one month of animation.”

Figure 1. Tippett Studio's proprietary Creature Manager is used to maintain a library of creatures and animation cycles. The tool allows an artist to select and preview animation by pressing the larger creature button, then selecting a combination of an appropriate physical appearance for that creature from a predefined library and placing any number of selected creatures into a Maya scene.

Hand animation is a challenging laborious process. “One guy does blocking, like moving chess pieces”, says Tippett Studio Animation Supervisor Todd Labonte. “You get it approved. We watch it over and over. You can go blind. We play it back in mirror image in our player or play it backward.” Labonte demonstrates playing back a scene of goblins invading the house, shown in their Flipper playback software, which can display a mirror image or play in reverse to help catch animation inconsistencies. Flipper is used to view both QuickTime and image frame sequences of DPX, EXR or TIFF with synchronized AIF audio. Flipper predates commercial Linux flipbooks, such as FrameCycler. At older studios, like Tippett, it's common to find proprietary Linux tools created before commercial options were available. Tippett has a team of eight Linux programmers to maintain and develop tools.

Figure 2. Flipper is Tippett Studio's proprietary flipbook image viewing tool. It allows an artist to view a series of individual image files as a continuous sequence. It also can be synchronized with audio, which is important for character animation. The artist can view the audio waveform to help with lip synchronization, as seen in the lower part of the screenshot. The tool also has a number of image and pixel comparison and analysis features, as seen in the dialog on the upper left. Post-camera moves can be previewed with Flipper before they are actually applied in the composite stage.

“Creature Picklist is a GUI-based Maya plugin for creatures that allows animators to see visual representations of character, which they can select for their scene”, says Darling. “In the case of Spiderwick, 'Goblin kits' were created as combinations of variants and blendshapes. We have shots that have more than 100 goblins. That's too many to animate using traditional methods. The numbers are also too small to make a commercial crowd system, such as Massive, a viable solution. We developed our own system called Swarm. For the Spiderwick shots, we instanced around 150 goblins and managed animation clip data to animate them as particles.”

Figure 3. Tippett Studio's Picklist allows an animator to select creature variants from a library of different combinations of paint schemes and body parts.

Figure 4. A view of Tippett's Swarm crowd system in Maya. The scene is choreographed by defining paths and actions for creatures to follow.

Figure 5. Tippett Studio's Picklist allows an animator to select specific predefined poses for creatures, such as this bird.

Furocious is Tippett Studio's proprietary hair, fur and feather system. It's a collection of plugins, scripts and executables used to place guide geometry onto scalp surfaces, visualize fur as GL curves in Maya, and grow procedural primitives at render/expansion time by interpolating neighboring guides at predetermined follicle root locations.