With the record-breaking Deathly Hallows: Part 1, director David Yates continues down the path of gritty realism as Harry (Daniel Radcliffe), Ron (Rupert Grint) and Hermoine (Emma Watson) hit the road to the find and destroy the Horcruxes before Lord Voldermort (Ralph Fiennes) regains full-strength and is unstoppable.
"Making the wizarding world believable is what we strive to do, as I've said many times before," explains Tim Burke , the overall visual effects supervisor, who collaborated on more than 1,000 shots with Double Negative, MPC, Framestore, Cinesite London, Rising Sun Pictures and Baseblack (not referenced here but responsible for such 2D work as the cafe fight & set extension; underwater Horcrux locket Scottish environments; and the cliff hanger with Voldermort).
"A lot of this is set in the Muggle world, apart from when they go to the Ministry of Magic, so there's a lot of photorealism and drama-led action," Burke continues. "It almost read like it wasn't a visual effects-heavy film. But there's a lot of work spread evenly throughout the film. There's a big opening set piece done by MPC where six of the characters turn themselves into Harry, so we end up with seven and they leave Privet Drive and end up in a big aerial battle with Death Eaters, which culminates with a motorbike chase through a tunnel and subsequent battle with Voldemort.
"There's lots of CG environments, CG digi doubles and a mixture of stunt work and face replacements. We used some new technology for facial capture [Mova  and its Contour system]. What I wanted to do is have a real physical performance of the character playing Harry Potter. But David was very keen that you believed that the character's personality was behind the mask, if you like, so what we wanted to do was capture their real performances and use that to drive the CG Harry. We made these transformations of hybrid combinations of Harry and the real characters. We then used Dan Radcliffe to play himself seven times. But, again, being meticulous about the performances, we got each actor to play out each shot for Dan as a character reference. We used motion control to shoot multiple passes for every single shot with Dan giving his performance for each of the characters: Ron, Hermoine, George, Fred, Mundungus and Fleur. We then split-screened them all together and the results work very well.
"There's also Kreacher and Dobby. Framestore has taken over the work of Dobby from ILM and we've updated the look subtly; and I think we've done some pretty nice character animation. I was very keen to bring in some more human characteristics for both Dobby and Kreacher [also done by Framestore] just to help the believability. For performance, we got Toby Jones back as Dobby and Simon McBurney to play Kreacher and we were very keen that they should be directed by David at the time of the scene to be filmed and not leave it as an afterthought. So it allowed David and the other principals to develop the scene with them."
One of the biggest challenges for MPC (which created more than 180 shots, under the supervision of Nicolas Aithadi) was the transformation sequence. The concept artists explored different combinations, blending features, sizes and skin textures from Harry and the other characters to create the hybrid designs. A custom rigging system was used to blend the data from the facial capture shoot, allowing animators to keep control of the fine details.
Once out of Privet Drive, the seven Harrys fly over London to escape the Death Eaters. MPC had to create CG thestrals: a cross between a horse and a dragon and extend Privet Drive's set. Greenscreen rider elements were combined with the CG creatures, digi-doubles and live-action footage. For the Death Eaters' chase, MPC created more than 100 CG characters, including full screen digi-doubles for Harry, Hagrid and the Death Eaters. The environment work included a CG aerial cloudscape, cityscapes and various set extensions. The chase culminates with a wand duel between Harry and Voldemort, with vfx encompassing explosions, wand effects, CG water and the bike crash.
Framestore (under the supervision of Christian Manz) keyframed Dobby and Kreacher, and to soften their features the team used the elves' original topologies from which to base the makeovers. Dobby's neck was smoothed out, his arms shortened and his eyes were made less saucer-like; Kreacher's nose was shortened, and ears were trimmed. They built on their recent skin shading technology, using multiple subsurface scattering techniques. To light scenes, they used mostly "bleed" cards of HDRI textures from the set projected on cards. That created a less diffuse style of lighting than they have done in the past.
Additionally, for the story-within-the story fairy tale, The Tales of Beedle the Bard, Framestore animated a crucial three-minute sequence directed by Ben Hibon and led by Sequence Supervisor Dale Newton. The Commercials team used the influences of stop-motion silhouette animator Lotte Reiniger  and shadow puppetry from India and the Far East. Added to this was the modern aesthetic of the single flowing shot. Working in Maya , Hibon and Newton created the story's characters, emulating the rigidity and motion of Reiniger's hand-cut paper silhouettes.
For the Burrows, Double Negative (under the supervision of David Vickery) created several different lighting styles for full 3D environment extensions. In addition, the location was much more prominent in this film, seen in many more shots and sequences, and it was immediately decided that a way had to be conceived of reducing the rendering time, in accordance with the volume of work. To extend it out into the distance, this ended up being a 2.5D environment, with the team rendering out multiple series of 3D dynamic elements to cards, which were then placed in 2D and layered up to create the illusion of depth.
For the Horcrux, Rising Sun Pictures (under the supervision of Sean Mathiesen) devised a contorted, tortured effigy/soul of Voldemort in the middle of some kind of seizure. Yates and Burke both responded well to the design, but requested that it should be 20 to 30-feet tall to be more menacing. They explored all kinds of meat, cloth, smoke, organs, ink and slime during pre-production. In the end, it was constructed of the slime and scum and detritus from the pond where the scene plays out in the film.
The Dementors were designed to be made of smoke instead of appearing merely shrouded in smoke. They used matchmoves, published geometry and digital doubles created in-house and brought them into Cinema 4D , played with ideas of separating smoke and building it from the ground and then merged them with cloth and robes and exported them out using FBX. The Maya cloth team took over and worked with the Houdini team and it was composited in Nuke .
Meanwhile, Cinesite (under the supervision of Holger Voss) used its proprietary csSkinShader for subsurface work on Voldermort's nose, generating textures from photographs shot using cross-polarized and non-polarized lights and lenses to extract highly detailed pore maps; csFluidShader to render Maya Fluids with RenderMan for the volumetric Patronus Doe effect in helping Harry find the Sword of Gryffindor; and csPhotoMesh to reconstruct terrain information from photographs for the establishing shot in the Windswept Hill sequence.
"It works well being split up because they're quite different movies," Burke offers. "Part 1 is very dense and sets up Part 2 brilliantly, which is more of an action movie."
Bill Desowitz is senior editor of AWN & VFXWorld.