You've probably read "Harry Potter and the Goblet of Fire" and maybe you've even seen the new movie. Harry, the boy wizard, competes in the Triwizard Tournament, facing merpeople, dragons, and his archenemy Lord Voldemort.
Each scene in the movie is carefully crafted to seem magically "real," so the audience can lose itself in the world of Hogwarts. Creating a film as high-tech as Harry Potter can take a year or longer.
One challenge in "Goblet of Fire" was to make a believable Horntail dragon that remained true to author J.K. Rowling's vivid description: "She writhed and twisted, furling and unfurling her wings and keeping those fearsome yellow eyes on Harry."
To create this dragon, Mike Newell, director of the film, called on the talents of Industrial Light and Magic (ILM), the special effects branch of Lucasfilm in San Francisco. Lucasfilm is known for its Star Wars series, but ILM has worked behind the scenes in many movies, including the past three Harry Potters.
For more than a year, a team of special-effects creators, led by Tim Alexander, worked hard to design the flying, fire-breathing Horntail dragon that we now see on screen.
"Goblet of Fire" was mostly filmed in Britain, so the dragon was first designed by Warner Bros. studio's art department in London.
"They do a bunch of drawings, different styles, different head and body shapes, until they have the one they like," Mr. Alexander explains. "Then they make a 'maquette,' which is basically a physical three-dimensional model."
The dragon model is smaller in scale than the dragon in the film, but it's still pretty large: It was shipped to ILM in a crate that was big enough to hold a car. "The [dragon's] body had wings that folded out; the tail popped off," Alexander says. The wingspan of the model is more than 14 feet, the length of a minivan.
Once the dragon model was put together, the design team could see how they needed to "construct" the dragon in the computer.
The first step was to photograph the model from every angle to gather details about its color and texture. They also made a 3-D scan of the maquette.
"The scan is like a laser beam. It tells the computer exactly where the surface of the dragon is," Alexander says.
After the scan, creators stored the shape and proportions of the dragon in the computer. They created the dragon's basic framework. Then it was time to add the details that would make the dragon look - and act - real.
Work was divided into two areas: "painting" the digital dragon's color and texture and developing the creature's movements.
One person worked on "painting" the dragon for 12 weeks, Alexander says. The painter programmed the details about the dragon's surface into the computer - bumpy and smooth areas, where it needed to be reflective, wet or dry - and created different dragon "looks."
At the same time, creature developers worked with animation director Steve Rollins to figure out how the dragon should move: How would it fly? How would it move if someone grabbed its leg?
For this, Mr. Rollins researched the real movements of birds such as owls and albatrosses, and also bats.
"When you see the movie, look for the head twitching, head cocked, and quick twitchy movements; these were all from the bird references," Alexander says.
Figuring out the movements took a few months. Rollins worked closely with Jimmy Mitchell, the visual-effects supervisor with Warner Bros. in London. Mr. Mitchell talked daily with Mr. Newell, the director. The dragon computer file could be played in London and San Francisco at the same time. Using the Internet like a telephone, they could discuss their ideas, changes, and how the next shot in the film should look.
Once Rollins determined how the dragon should move, he ran animation tests, trying out different versions of the same scene. "Where the dragon crawls across the rocks, we'd do one version with it using its hind legs, another where it's crouched down, using the batlike hands on its wings to crawl," Alexander explains.
Finally, after three to five months of preparation, the dragon had texture and color and was moving well. It was ready to start "shot production." This is when the dragon is manipulated into film scenes, "acting" alongside the real actors - in this case Harry, who was trying to accomplish a tournament task.
"The shot production went on for another nine months," Alexander says. The whole process involved at least 50 people for more than a year.
Out of all the things the dragon had to do, breathing fire was one of the toughest to re-create.
"Fire is a natural occurrence, everyone knows what it looks like. They know if it looks fake," Alexander says. "We needed [the dragon's] fire to be directable, and that took a long time."
In the end, they mixed footage of real fire with high-tech computer effects. The result is a believable, ferocious, fire-breathing dragon.
Animation is difficult, Alexander says. If the movement doesn't look right, the scene is ruined. "It is difficult to do animation and not make it look weird," he says. But this dragon turned out even better than he had expected.
Not all the dragon scenes in "Goblet of Fire" are computer-animated. Although the digital dragon is in more than 140 scenes, a large puppet dragon appears twice, in the first dragon sequence when Harry is in the forest. See if you can tell the difference.
Dragons haven't always looked as lifelike as the Horntail in "Goblet of Fire." Long before high-tech computer animation, special effects involved hand-drawn animation and stop-motion shooting, which meant piecing each frame or pose together to form movement. Here are how some famous dragons came to life in movies from the past.
Sleeping Beauty (1959) The dragon in this Disney animation was hand-painted and designed by Eyvind Earle. At the time, his approach was viewed as bold and unique. The movie was made using a stop-motion camera, with each frame photographed three times (once with a red filter, once with a blue filter, and once with a green filter). The negative was then printed onto film. A flame thrower was recorded to create the sound effects of the dragon's breath.
Dragonslayer (1981) Industrial Light and Magic (ILM) worked on this Paramount picture. Back then, filmmakers used a mechanical dragon, a model that was hooked up to a computer. The dragon's movements were programmed in. During filming, the computer moved the dragon and this caused "motion blur," making the dragon's actions look more realistic. ILM called this approach "go-motion." In stop-motion, a model is moved once per frame, creating jerky movement. Using go-motion, the dragon moved a few times per frame.
The Neverending Story (1984) The dragon in this movie by Warner Bros. looked more like a big white fluffy dog with feathers. It was a model produced by Jim Henson Creatures, of the Muppets fame. It operated like a mechanical puppet. This was a popular form of animation before digital effects really took off.
Dragonheart (1996) It took a team of 96 people at ILM to create Draco, the first dragon to be made using computer graphic imagery (CGI). On screen, this digital dragon was 18 feet high, 43 feet long, and had the voice of actor Sean Connery. The only part of the dragon that wasn't computer-animated was its tongue. One scene takes place in the dragon's mouth. To create a cavelike mouth, ILM made a full-sized mechanical tongue and jaw that could be moved by machines. Actors stood in the mechanical mouth to film the scene. The rest of dragon was added to the scene later using computer animation.
Sources: www.imdb.com, www.harrypotter.warnerbros.com