by Joe Tracy, Publisher of Digital
Media FX (digitalmediafx.com)
years ago, PDI (a subsidiary of DreamWorks and the animation
company behind ANTZ) was handed the challenge of
breathing life into the characters and environments of
Shrek. The task would be much more difficult than
with ANTZ, simply due to the variety and vast shape
differences of Shrek characters.
have Shrek, who's huge, Fiona who is small and lithe,
and a short, squat Donkey," says Simon J. Smith,
who headed the layout team. "So it was sometimes
difficult to find the right camera angles for everyone."
shapes, sizes, and variety weren't the only challenge,
however. The directors were insistent on a realistic and
A Whole New World
"When we started Shrek, we wanted to make
a fairy tale come to life; as if you opened a storybook
and stepped into that world," says Andrew Adamson,
one of the film's directors.
envisioned a magical environment that you could immerse
yourself into," adds Aron Warner, one of the film's
producers. "Every leaf on every tree moves, the dirt
moves, the dust rolls; there's a sense of atmosphere,
a sense of weight to all the props. You can almost smell
the world of Shrek would ultimately involve 36
separate in-film locations, which DreamWorks claims is
more than any previous computer animated feature.
Research Trips and In-Film Locations
The first step in bringing the environments to life was
research trips by the art directors. On one trip, art
director Douglas Rogers was chased by an alligator while
checking out Swamp locations in South Carolina. Rogers,
along with fellow art director Guillaume Aretos traveled
to several locations inside the U.S. (like Hearst Castle)
and outside the U.S., like the Dordogne region of France,
which also served as the inspiration for the settings
in the movie Ever After.
art directors were impressed enough with the Dordogne
region to make it the inspiration behind Duloc in Shrek.
swamp aspects of the research trips provided inspiration
for Shrek's swamp home.
designed Shrek's swamp to be a very organic environment,
more like a hovel that he built using materials he found
in the swamp," says production designer James Hegedus.
"It's wet, mucky, and overgrown; perfect for him."
locations were finalized and as demonstrated by past DreamWorks
animated movies, color and mood was of the utmost importance.
[Duloc] a very linear, angular setting; pristine, minimal,
and hard," says Hegedus. "The colors are cool,
the tones are subdued. What we tried to do was reflect
the characters in their environments. Shrek is tied to
earthiness, Farquaad to a more controlled space, and Princess
Fiona is between those two worlds."
the characters into the Shrek environment and animating
them with many unique camera moves (like crane shots)
presented some of the biggest challenges.
enhanced version of PDI's proprietary facial animation
software/hardware was used to bring the character performances
to life. Since performances are enhanced by expressions
and emotions, those must come through very clearly to
the audience, without looking staged.
is an ogre, but at the same time, he has the same range
of emotions as any of us," says supervising animator
Raman Hui. "In fact, the most challenging animation
to do was when Shrek is hiding what he is really feeling;
saying one thing, but thinking something else. Animators
are just like actors. It's up to us to put all those emotions
into the face."
characters could perform, however, they first had to be
Layering Shrek Characters
Using a layering system that is based on human anatomy,
the PDI team was able to properly convey a wide range
of emotions, attitudes, and expressions. Here's how it
works, according to DreamWorks:
the skull of the characters is formed in the computer
and covered with computer recreations of the actual muscles
of the face. The skin is then layered over and programmed
to respond to the manipulations of the muscles as would
a human face, complete with wrinkles, laugh lines, and
other imperfections. Hundreds of controls are wired into
the face like human nerves, enabling the animators to
go far beyond the speech phonemes for the correct lip
complexity of the software allowed PDI to apply percentages
to command combinations in order to achieve the desired
same type of layering worked for the body of each character,
as well. A skeleton was built then populated with layers
of muscles, skin, and even clothing. PDI used what they
call a "Sharper" program for the deformations
of skin and clothing. According to DreamWorks, the Sharper
program, "is a layering process that deforms the
surface from the inside out. When you modify the innermost
layer, the change extends outward to ultimately change
the exterior shape. It is taken from the same principle
that causes your arm muscle to flex when you bend your
used a shader (these programs have names, but PDI is being
quiet about what software it uses) to assist with its
rendering in order to achieve realistic skin for all the
characters. This involves changing various rendering properties
like the changing of textures (should the princess have
smooth skin or bumpy skin?) and other specular controls.
Lighting is one of the most difficult and important aspects
in animating a movie. Like color, lighting can help shape
the mood, environment, and realism of the scene. Just
take a look at the credits
and you'll see that there were nearly three dozen Shrek
artists dedicated to lighting alone.
must worry about dozens of elements in lighting a scene,
from mood lighting to how light penetrates, refracts,
and reemerges from a character's skin.
to DreamWorks, "More concentrated light created a
natural radiant shine, while broader sheens simulated
the top layer of dead skin we all have. It was a difficult
balance to maintain because too much shine would result
in a look like a plastic mannequin."
One of PDI's challenges with the Donkey's fur was making
the fur flow smoothly so that it didn't look like a Chia
Pet's fur. This fell into the hands of the surfacing animators
who used flow controls within a complex shader to provide
the fur with many attributes (ability to change directions,
lie flat, swirl, etc.).
was then the job of the visual effects group, lead by
Ken Bielenberg, to make the fur react to environment conditions.
Once the technology was mastered, it was able to be applied
to many aspects of the Shrek movie including grass,
moss, beards, eyebrows, and even the threads on Shrek's
hair was a different story. It required a separate rendering
system and a lot of attention from the lighting and visual
Let There Be Fluid
PDI used its Fluid Animation System (nicknamed FLU) for
any scenes requiring fluid rendering. According to DreamWorks,
"the system enabled them to create a range of liquids
with different viscosities - from water to mud to beer
to lava to milk. Imagine digital spheres flying around
in free space, which, as they collide, form a singular
isosurface, which can be more or less dense resulting
in different thickness'.
FLU, animators had full control over all aspects of liquid
including the mixing of liquids, direction of the flow,
and even collision aspects of liquid (like hitting the
bottom of a glass).
what about characters interacting with fluid? There was,
of course, research done first.
took one of the guys, put him in a yellow slicker, and
dumped mud all over him," says Ken Bielenberg, the
film's visual effects supervisor. "Besides being
fun, it gave us a good reference to see how mud behaves."
The Illusion of Life
From lighting to fur and layering to fluid control, PDI
met the challenge handed to them to bring Shrek
to life. The audience will never think of the small details
that took years to create or about how many people it
took to bring Shrek to life. But that's fine with DreamWorks.
Their job is to mask the effort that went into the animated
movie so that people don't think about those things. DreamWorks
wants people to get lost in its world.
director Andrew Adamson says, "All the effects are
there to bring a richness and a reality to our world,
which is invaluable when you're trying to create an illusion
Tracy is the publisher of Digital
Media FX (www.digitalmediafx.com)