 |
| BUSINESS |
|
|
Virtual Fall Guys
In The Wings?
Animated Characters May Fill In For Stunt
Artists
February 26,
2002
By ANDREW BRIDGES, Associated Press
LOS ANGELES
-- The gangly skeleton pauses at the top
of the staircase and then, fearlessly, dives headfirst,
crumpling in an apparently bone-jarring fall.
Petros
Faloutsos chuckles as he replays the clip on his laptop
computer. Again and again, the UCLA scientist commands the
virtual character to dive.
The animation is primitive,
the technology complex.
Beyond the initial command to
jump, the fall is completely unscripted. Physics, not the
computer animator's mouse, controls the
action.
Although just a prototype, Faloutsos believes
his animation program will one day allow virtual stunt artists
to replace their flesh-and-blood counterparts in performing
otherwise deadly feats of derring-do.
"Maybe people
will be directing virtual actors, and we'll have to give them
Oscars, too," Faloutsos mused.
The brief clip is a
glimpse into the nascent field of physics-based animation. The
technique, whether used for movies or video games, strives to
create a virtual world consistently guided by the same
physical laws that give order to the real world.
"It's
the Holy Grail of character animation. Everybody wants to do
it, but there's not a whole lot of it out there right now,"
said Damien Neff, senior artificial intelligence designer for
NFL Fever 2002, a Microsoft video game that makes limited use
of the technique.
As the technology matures, real stunt
artists have mixed feelings about the effect they believe it
will increasingly have on their craft.
"There's a
positive side and a negative side: To talk positive, it's made
it safer to do a stunt - you don't have to lay your neck out
on the line as much as you used to. But it's taken some cash
away, also," said Ben Scott, a Hollywood stuntman who works on
the HBO series "Six Feet Under."
Traditionally,
animators have relied on their own talents to draw characters
that appear to move naturally.
Movie studios and game
developers also bank increasingly on libraries of hundreds of
stunts amassed by filming the sensor-studded bodies of real
performers.
Those "captured motions" can then be
matched to virtual characters and inserted into movies or
games, where they appear real as they move within
environments, such as sinking ships or burning buildings, that
could put real actors at risk.
Animation systems such
as that created by Faloutsos and his former colleagues Michiel
van de Panne, Demetri Terzopoulos and Victor Ng-Thow-Hing,
attempt to trump both.
The key is using mathematical
formulas that only loosely choreograph the movements an
animator wants a character to undertake.
Command, say,
a character's arm to move, and the momentum will force its
torso and head to shift, as well.
The range of motions
available to a character ultimately guide how it behaves, as
does its own computer-generated sensitivity to both gravity
and any forces imparted by its virtual
surroundings.
Different environments, for example, will
prompt the same character to move differently - and
unpredictably. A fall on slick ice won't be the same as one
down a steep flight of stairs.
In movies, physics-based
animation techniques have been used to render inanimate things
such as the waves in "The Perfect Storm" or the shock of blue
hair that coats James P. Sullivan in "Monsters Inc."
In
video games, they crop up in programming that simulates such
action as racing or flying competitions.
With animated
characters, attaining of realism is far more difficult,
however. Emotion can influence movement as much as gravity
does.
"You can tell from how someone is walking if
they're effeminate or angry. How would you account for that in
a physics-based system?" said Darren Hendler, technical
director at Digital Domain Inc., a Los Angeles special effects
studio.
In the forthcoming film "The Time Machine,"
Digital Domain used a physics-based animation technique to
render the collapse of thousands of skeletons of people turned
to dust and bone.
Animators still shy away from using
physics to model the movement of people, however. They say the
human eye is just too good at spotting even the slightest hint
of fakery.
But Faloutsos believes future systems will
allow directors to guide characters as they do live
actors.
"The ultimate goal is to have a totally
complete human inside the computer that you can direct," he
said.
Until then, officials with the Screen Actors
Guild know there will be work for the more than 6,600
Hollywood stunt artists the union represents.
"People,
quite honestly, like to see human beings on the screen," said
Ilyanne Kichaven, a guild spokeswoman.
"There's still
something an actor can bring to the screen that a
computer-generated person cannot."
|
| |
|
E-mail
story
