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Last Updated: Friday, 30 June 2006, 17:03 GMT 18:03 UK
The rise of the pixel performers
BBC Click's Spencer Kelly
By Spencer Kelly

Movie special effects have been around for pretty much as long as the movies themselves, but with the latest digital cameras, editing equipment and animation technology it is has become possible to work more magic than ever before.

Peter Jackson's King Kong
Peter Jackson's King Kong is based on the 1933 movie

Even on Click's shoe-string budget, it is possible to make me disappear. In fact, on our budget, I have often been tempted to do just that.

Of course, when you start spending serious money, truly stunning effects are possible. But how is it all done?

Well, let us start off with some visual effect basics.

If I wanted to vanish, it would be quite simple to achieve. We would simply shoot the same scene twice from exactly the same camera angle, one with me and one without me. Then we would just have to mix between them.

If you want to fake the background of a scene, you could shoot the action in front of a blue or green screen. It is very easy to remove either colour from the shot, and replace it with any picture you like. That means you can place the action anywhere in the Universe, without actually having to leave the studio.

Everything you are seeing in there, all those actions, the hundreds of thousands of them, are all unique
Joe Letteri, Weta Digital
With these basic principles, but executed a lot more carefully, the biplanes from a scene in King Kong were shot in a studio and then composited onto a New York skyline.

And using similar methods, a cameraman can be removed and the studio background replaced by deep jungle.

Entire cityscapes can be created by software and added to the backdrop of a scene.

Using computers to control the camera movements, it is possible to match the movements of the cameras to the movements of the computer generated backgrounds to create one very deep shot where perspective is maintained.

That way everything appears to move past the camera at the right speed, whether it is really there or not.

Rings intelligence

WETA Digital's Visual Effects Supervisor, Joe Letteri

The special effects house that created King Kong, Weta Digital, is certainly known for its epic visual effects.

As well as the virtual buildings and objects in King Kong's world, they brought to life thousands of computer-generated warriors for the battle scenes in the Lord of the Rings trilogy.

It is effects like these that have won Weta Digital's visual effects supervisor, Joe Letteri, three Academy Awards for his work on Lord of the Rings and King Kong.

He told me about his computer program Massive, specially written to handle large numbers of computer-generated characters in a scene.

Joe Letteri says: "The whole reason behind Massive is its artificial intelligence. It is the idea that you create these as unique agents.

"Each agent, each soldier in the battle has its own brain. He can see another agent coming towards him and decide if it is friend or foe, and he can decide to react, or attack, or flee, or get killed.

"So, everything you are seeing in there, all those actions, the hundreds of thousands of them, are all unique."

Character acting

What is most important is the choices that an actor makes when they are actually performing the character
Joe Letteri, Weta Digital
Computer generated imagery (CGI) is becoming powerful enough to create not only realistic effects, but also believable computer-generated characters in leading roles. But in King Kong, real actors still play a part.

Instead of creating them from scratch, Kong's facial movements were captured from the face of actor Andy Serkis, the same man whose body movements and voice were captured to create Joe's other famous creation, Gollum.

So are we moving towards a time when we can get rid of human actors and just use voice artists and computer generated characters?

Joe Letteri says: "I don't think so. That was the lesson we learnt on Gollum. Andy Serkis was brought in just to be the voice, but what worked really well was that you had an actor there present in the scene doing all of this.

"There was no sense of replacing Andy; Andy was the actor behind Gollum. For me, the best way to create a character is to work with an actor.

"Something like motion capture, where you can put dots on an actor's body, or in the case of Kong when you put dots on the face and use that to translate the actor's physical movement directly to a character, is really important and is a really great step for bringing these things to the screen.

Dreamworks Animation's Supervising Animator David Burgess
We shoot the actors recording the lines in the sound studio and sometimes that is really helpful to see what they bring to the performance
David Burgess, DreamWorks Animation SKG
"But it is actually not the most important step. We also have a team of very good animators who can do the same thing.

"What is most important is the choices that an actor makes when they are actually performing the character.

"[It is] those subtle split-second shifts in timings and reactions to other actors that you bring and really give life to the scene."

So it is nice to hear we humans are not obsolete yet. That is, at least in live actions films.

But what about the films where everything is computer-generated?

The new animated movie Over the Hedge is the latest fully animated movie release from Dreamworks Animation.

There teams of artists turn hand-drawn cartoons into 3D computer characters, and then create or render the movie frame by frame, with the help of powerful workstation computers plus a lot of processing power in the backroom.

Of course, real actors are still needed to provide the characters' voices, but it seems that even when all the characters are computer-generated animals, the animators can still make use of the human actors' performances.

Fire and water are so infinitesimally complicated to model that animators can only create rough approximations on screen

DreamWorks Animation SKG's supervising animator David Burgess says: "We shoot the actors recording the lines in the sound studio and sometimes that is really helpful to see what they bring to the performance.

"William Shatner is really funny to watch," says Mr Burgess. "He is so big and so theatrical and it is fun to look at that and see what he brought to it."

It seems that the performance artist can still bring something to a performance, which an artist cannot.

Breaking barriers

I think movie goers are getting very much attuned to the special effects [and] much more aware of when things work and when things don't work and that's a good thing
Joe Letteri, Weta Digital
So is there anything else that is still a challenge for animators?

Certainly mother nature has always been difficult to recreate.

Fire and water are so infinitesimally complicated to model that animators can only create rough approximations on screen. That said, with more experience and more processing power simulations of nature are getting very good indeed.

Chief Technology Officer for DreamWorks Animation SKG Ed Leonard says: "Today, things like fur are really complicated and in Over the Hedge we have a lot of furry characters with just a tremendous amount of fur, whereas even a few years ago having one character with fur and having that character on screen for a long time was a big technical challenge.

"All of these things are ultimately about removing the limitations for our film makers and letting them bring to life a film that they want to make. "

Joe Letteri says: "I think movie goers are getting very much attuned to the special effects [and] much more aware of when things work and when things don't work. And that's a good thing, it is good to be held up to a higher standard."

There is little doubt that computer generated visual effects can help to hype a movie, but a quick look at the films which have managed to sustain audiences after the initial hype and recouped the most money are the ones the critics agree have two things computers cannot do: great writing and great performances.

SEE ALSO
Visual effects prize for Rings
21 Mar 03 |  Entertainment
Meet Gollum and friends
11 Dec 02 |  Entertainment
Digital effects bring Rings to life
16 Nov 01 |  Science/Nature

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