Animation meets physical reality
By Jeyling Chou
Oct. 6, 2002 9:00 p.m.
Physics. The science that dictates how the planets revolve
around the sun; the mysterious explanations behind the occasional
embarrassing fall as we navigate our way up the steps of Bruin
Walk. Experienced by every body of matter, defined by Sir Isaac
Newton, and now, cleverly virtualized by UCLA computer science
professor, Petros Faloutsos.
Faloutsos and a team of computer scientists are developing a
software program which animates a background and a character
entirely based on physics.
Faloutsos’ project focuses on the biomechanics and motor
control of a virtual character.
The character is an anatomically correct human skeleton. The
background can be anything imaginable by the creative computer
animator.
“In reality, you and I move under the forces of gravity.
We can now simulate that in a computer,” Faloutsos said.
Our skeleton friend can tumble down stairs, react to being hit
by a ball, and regain a standing position entirely independent of
the animator’s controls.
If the character is commanded to jump down a flight of stairs,
only the laws of physics govern the movements of its body parts and
bone-jarring crash. Each fall, each slip in a different environment
is unpredictable and unscripted.
Most modern animators animate their characters by hand with
iteration after iteration of programmed scenes. If the
background upon which the character is moving is changed by a
slight variation, the scene must be re-done.
“In physics-based animation, if you change the
environment, you just let the character fall,” Faloutsos
said.
And it falls with only the accurate and unfortunate adhesion to
the same forces which cause our little bumps and scrapes. It
requires no commands from the animator in the way that the body
twists, or the legs crumple.
Not only can the character fall and trip and be hit in the face
by rubber balls of various sizes, it almost has a small degree of
reactive intelligence, according to Lucio Flores, a research
assistant on the project and UCLA graduate student.
“These skeletons walk along and when you push them, they
put their hands out and try to protect themselves,” he said.
“And if you knock them over just a little, they’ll take
a protective step backwards.”
The software has many possible applications in video and
computer games. In games of the racing genre, for example, skid
marks and flying car parts may soon take on a life of their
own.
“In video games, you don’t want
predictability,” Faloutsos said. “You don’t want
the user to know exactly what’s going to happen
next.”
Faloutsos, however, does have an idea of what he wants to happen
next. Perhaps one day, the software could create virtual stuntmen
to replace real people in action movies. A 3-D computerized model
of your favorite actor would be capable of completing stunts that
could be potentially fatal to a real stuntman.
So could stuntmen who devote their careers to performing the
dangerous feats in those edge-of-your-seat action movies be out of
a job in the near future? Apparently, they’re not too
worried.
Eric Mansker, a stunt coordinator who’s done stunts for
movies like “Independence Day” and “Mighty Joe
Young,” believes that audiences enjoy the human interaction
when watching death-defying acts on the big screen.
“People go to watch stunts because they want to see real
people do it,” said Mansker, a graduate of the UCLA Drama
School in 1976.
“Once you know it’s not real, it’s like
watching a cartoon,” he said. “Who are you going to be
emotionally invested in? A virtual character or someone
real?”
Chris Caso, a fellow stuntman whose latest role was stunt double
to Ben Affleck in the upcoming movie “Daredevil”,
agrees.Â
“Who’s going to see a movie with Joe Computer?
He’s a star, but he’s not real. People like real
flesh,” he said. “I’m not that worried about
it.”
Caso also expressed, however, that sometimes the stunt double
business gets a little too dangerous.
“You make a lot of money doing the scary stuff, but
sometimes you wish there was some kind of software to replace you
or take you out of the dangerous stuff,” he said.
Caso and Mansker both agreed that they saw something like this
coming from a mile away.
“Most stunt guys have been talking about this ever since
they started doing computer-generated images,” Caso said.
“Most of us aren’t too worried about it because most
of it looks too phony. But eventually, they might get it
right,” he said.
Stuntmen can be at ease for the time being because Faloutsos
considers his animation a work in progress.
“We would like more artificial intelligence at some
point,” he said. “We would like this character to do
more intelligent things besides reacting to stuff.”
The next steps toward real artificial intelligence are
perception, the ability to learn new behaviors, and ultimately,
cognition and the understanding of abstract ideas.
Fundamental forms of physics-based animation have already been
used in Hollywood. The recent movie, “The Time Machine”
used this science for a scene of crumbling skeletons, which
required large amounts of flying bones and dust.
“That’s just the tip of what Petros is doing,”
said Doug Roble, director of software at Digital Domain which
worked on “The Time Machine.”
“Not only does he have to deal with these forces like
gravity and explosions, he has to deal with these control systems
that keep the character upright while dealing with all these
forces,” said Roble.
Faloutsos’ tumbling skeleton could change the face of
digital media, and Hollywood is anxiously waiting.
“We’ve got our eye on him,” Roble said.
