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Double Negative Goes Organic for Goblet of Fire

Under the guidance of vfx supervisor Mark Michaels and CG supervisor Richard Clarke, Double Negative created 500 shots in 15 months for Warner Bros. Pictures HARRY POTTER AND THE GOBLET OF FIRE (opening Nov. 18), more than any other vfx facility working on the movie. The work comes on the heels of highly acclaimed Double Negative work for SAHARA, KINGDOM OF HEAVEN, THE JACKET, PRIDE & PREJUDICE, DOOM and BATMAN BEGINS.

HARRY POTTER AND THE GOBLET OF FIRE takes the series into darker territory as Harry faces arch nemesis Voldemort (Ralph Fiennes) for the first time. Director Mike Newell, new to the franchise, wanted the visuals to reflect this change in tone, as Michaels explained, All the visual effects weve created are based on an organic theme. From the outset Mike was clear that he wanted to steer clear of an overtly magical approach, and instead give it an old-worldly feel based firmly in reality. As the series progresses and the story becomes darker, its important for us to reinforce the fact that the characters are at risk, and living in a dangerous world. In that respect we used as many real-life references as possible when creating the shots.

Double Negatives work on the project includes key sequences such as the Portkey journey to the Quidditch World Cup, the train journey to Hogwarts, Mad Eye Moodys demonstration of the Unforgivable Curses and the climactic confrontation between Harry and Voldemort.

Double Negative faced two tasks in the realization of this scene, where new teacher Mad-Eye Moody demonstrates the Unforgivable Curses on an unfortunate spider. First was the design and construction of Moodys mad eye, and then the creation of a photorealistic spider.

Working from early concept art, Double Negatives Phil Johnson created several builds of Moodys mad eye incorporating complex clockwork structures, before settling on a simple mechanical design. The production decided that it didnt want every Mad-Eye Moody scene to become an effects shot, so the final design is a combination of our work and the creature effects departments prosthetic designs, added Michaels. That way the physical eye could be used on set, leaving us to make digital enhancements when the eye was required to move further than the model would allow. This approach meant that the team faced the challenge of working without tracking markers, but they solved the problem with proprietary software Photofit, using plate detail for camera tracking.

The second element of the sequence is based around the unlucky spider, which Moody first enlarges and then demonstrates the Unforgivable Curses on, commanding it to fly around the room before using it as a guinea pig for the killing curse. The performance required of the spider meant that CG was the only option, and Double Negatives task was to make him look and move just like the real thing. To fully study the chosen breed in detail, the team adopted a pet Whip Scorpion spider and 3D animators Nick Symons and Nicola Brodie begun examining its movements and reactions.

Michaels explained: The movement of the creature had to be realistic, but at the same time we had limited artistic license to change its movements to emphasize the effects of the curses. By the end of the scene the audience should feel sympathy for the spider as it contorts into its death throes, so it was important for us to give it some character. The build took place as a two-stage process, with head of creature development Martin Parsons first modeling the major features in Maya before creature supervisor Ged Wright added a second, higher level of detail in ZBrush. Subsurface and translucency shaders were written in order to simulate translucent qualities of the spider, which were made full use of during the lighting phase. Lead compositors Peter Jopling and Niki Wakefield integrated multiple CG layers of the spider in Shake to establish the final look.

A later Hogwarts scene sees Harry and his friends conduct a late night research session into the effects of Gillyweed. Double Negative was asked to bring a touch of magic to the famous Hogwarts library by creating and animating 3D reference books that float to and from the shelves, sorting themselves as they go.

THE GOBLET OF FIRE introduces a new method of transport to the series, the Portkey. The Portkey used by Harry and the Weasleys looks just like a battered old boot, but upon touching it transports them to the Quidditch World Cup. Double Negatives job was to design the visual representation of the journey, with early concepts featuring wormholes and inverted tornadoes. We wanted to take the audience on a ride and to convey a real sense of turbulence so they lose touch with reality and whats up and down, suggested Michaels. After experimenting with particle passes and fluid dynamics we settled on a vortex where the world dissolves around the characters as a new location appears around them. To achieve this the team used proprietary stitching software Stig to create a giant panoramic matte painting of the original location of Stoatshead Hill in England, and in-house tools that procedurally build geometry from match move tracking markers. Senior matte painter Dimitri Delacovias gave further detail to the landscape in Photoshop. Lead 3D artist Ryan Cook then transformed it into a swirling mass of particles that lead compositor Andy Lockley blended together in Shake, while technology originally created for BATMAN BEGINS was used to create digital doubles of the cast to complete the scene.

Since its formation in 1998, Double Negative ( has firmly established itself as a leading player in visual effects production worldwide. Located in the heart of Londons Soho, the company is a pre-eminent visual effects studio with more than 30 feature films to its credit.

Bill Desowitz's picture

Bill Desowitz, former editor of VFXWorld, is currently the Crafts Editor of IndieWire.