10 Hot Visual Effects Teams Reveal How They Made Movie Magic on 'Harry Potter,' 'Captain America,' 'Transformers'

About 1,200 visual effects shots were used for "Harry Potter and the Deathly Hallows: Part 2," the last installment in the film series.

Some of the leading VFX supervisors share the unique challenges they faced in fashioning the year's most jaw-dropping (and delicate) spectacles as they prepare for the Academy bake-off.

Now that the Thanksgiving leftovers are gone, it's time to look ahead to a bake-off. In early January, the Academy's visual effects branch will invite the VFX teams of 10 films (up from seven last year) to showcase their work before Oscar voters. The titles will be presented Jan. 19 at the Samuel Goldwyn Theater as part of the visual effects bake-off, from which the category's five Oscar nominees will be chosen. Here, some of the leading VFX supervisors hoping to land a berth reveal the unique challenges they faced in fashioning the year's most jaw-dropping (and delicate) VFX spectacles.

? The Adventures of Tintin

Joe Letteri, senior VFX supervisor, Weta Digital

To capture the essence of artist Herge's comic book character, Letteri and his team combined careful design work with performance-capture techniques.

"We were trying to create characters that you felt were alive in this world that they belonged to. The most challenging aspects -- there were two -- were getting Tintin's face right, because of the subtlety that we needed to convey but still not get too far away from the original design; and from a purely technical, number-crunching standpoint, probably Snowy because the dog had all that performance complexity as well as all the fur."

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? Captain America: The First Avenger

Christopher Townsend, VFX supervisor

Townsend became a weight-loss guru for actor Chris Evans, who appears at the start of the film as a skinny Steve Rogers before he transforms into the muscular Captain America.

"In order for the story to be believable, we had to create a character that people never questioned was actually an effect. We used a technique called mesh warping. It's taking the edges of the character and pushing all the edges closer in, so that his overall body mass has reduced. Frame by frame, we reduced his height about 5 or 6 inches, thinned out his cheeks and his neck, reduced his shoulders, his waist, everything about him."

? Harry Potter and the Deathly Hallows Part 2

Tim Burke, senior VFX supervisor

The Potter VFX team produced its most complex work in the series, for the first time creating a completely CG-rendered Hogwarts School of Witchcraft and Wizardry.

"This film required us to build the environment for Hogwarts and all of the staged action in the majority of the film: the battle for Hogwarts and the film's showdown between Voldemort and Harry. There was huge R&D -- over a year -- to build this virtual world where we could stage all of this fantastic action, as if we really were able to go to the world of Harry Potter and Hogwarts and film there."

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? Hugo

Rob Legato, VFX supervisor

The team took an artistic approach to the VFX, aimed at seamlessly joining the special effects with the cinematography, production design and 3D elements of the production.

"We're using all the latest technology, but we're not concerned with completely blowing you away -- though we have train crashes. I would stress it's an artistic achievement; what it looks like and feels like is the achievement. The movie doesn't stop and turn into a VFX moment. Creating VFX for 3D and making it seamless is very difficult and time-consuming. You can't hide behind a 2D replication effect."

400: Number of artists from visual effects company Pixomondo who worked on the 800 VFX shots in Martin Scorsese's 3D Hugo

? Kung Fu Panda 2

Alex Parkinson, VFX supervisor, DreamWorks Animation

The film's climactic battle on water shows how the DWA team strived for greater stylization on the Panda sequel.

"With the cannon fire effects and cannonball effects, we weren't going for realism. We studied references on cannons and how they fired, but the idea came from the story that [the film's villain] Lord Shen had taken the technology of fireworks and diverted them. They were extremely stylized and based on Chinese paintings, beautiful but terrifying at the same time. The water doesn't move like real water. It accentuates the action and works with the animation to increase the experience."

50,139: The number of digital splinters and pieces of debris that go flying in the most complex scene of Kung Fu Panda 2, in which the tower gets destroyed

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? Real Steel

Erik Nash, VFX supervisor, Digital Domain

Director Shawn Levy wanted the boxing matches between 8-foot CG robots to feel visceral and natural.

"The team took virtual production techniques on location by first choreographing and shooting performance-capture bouts. Then, using the Simul-Cam system that was developed for Avatar, we were able to 'see' the robot fights on a monitor during principal photography. The camera operator could move with the robots and react to what was happening."

? Rise of the Planet of the Apes

Joe Letteri, senior VFX supervisor, Weta Digital

The buzz surrounding Rise of the Planet of the Apes has centered on Weta Digital's photoreal-performance-captured primates, including lead ape Caesar (Andy Serkis).

"Caesar has almost no dialogue, so it's all done with his facial expressions. We did extensive research. There's the look, the physicality -- bones, muscle, tissue, fur. But that's just the starting point. What we're really after is the performance."

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? Thor

Wesley Sewell, VFX supervisor

The illustrations of comic book artist Jack Kirby, the skies of landscape artist J.M.W. Turner and hundreds of pictures from the Hubble telescope were among what Sewell and his team drew upon to bring the rich world of Marvel Comics' Thor to the screen.

"The challenge was to take the fantastical pictures from the comic books of Thor and bring a classical, fine-art approach that [director] Kenneth Branagh wanted. Bringing comic book art, pop art and fine arts into a cinematic form was our goal."

? Super 8

Dennis Muren, VFX supervisor, Industrial Light & Magic

An Oscar winner for such films as E.T.: The Extra-Terrestrial and Jurassic Park, Muren returned to his roots to make Super 8, which director J.J. Abrams conceived in the style of '80s effects movies.

"That means the shots last a lot longer than they do now -- so there's more room for scrutiny on [the visual effects]. They also tended to be a little brighter. That's the aesthetic, which dictated how we're going to do everything. Because the story is also seen from the kids' point of view, during the train crash, things flipped higher than they would have, exploded a little bigger than they might have."

8: Number of Oscars (including two special achievement awards) won by veteran VFX supervisor Dennis Muren (Super 8), a record in the field

? Transformers: Dark of the Moon

Scott Farrar, VFX supervisor, Industrial Light & Magic

The third movie in the franchise raised what was already a very high bar as far as visual effects were concerned. The Driller, the snakelike creature that attacks a Chicago high-rise, represents some of the most complex effects that ILM has ever tackled.

"The Driller wrapped around the tilted building demonstrates everything we put into these movies -- the look, the lighting, the reflections. We're trying to go with a photorealistic look. No less than 50 artists touched one of those big shots. And we had 40 shots like that. And they were 3D. The biggest asset that ILM ever created was The Driller, with 70,051 parts. In comparison, Optimus Prime had 10,108."