The
Making of Shrek
By Iain Blair
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Shrek
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"Shrek,
a bad-tempered ogre, is not having a good day. His precious solitude
has been shattered by an invasion of annoying fairytale characters.
There are blind mice in his food, a big, bad wolf in his bed, three
little homeless pigs and more, all banished from their kingdom by the
evil Lord Farquaad."—
By Iain Blair
Welcome to
the wonderful world of Shrek, a world also populated by a beautiful
princess, a talking donkey, and, of course, a fire-breathing dragon.
Based on the children’s book by William Steig, Shrek is the big
new release from PDI/DreamWorks, the team that created the 1998 blockbuster
Antz. A visually rich and technically challenging computer animated
film, Shrek is an irreverent comedy featuring the vocal talents of Mike
Myers, Eddie Murphy, Cameron Diaz and John Lithgow married to the work
of over 275 artists, computer animators, software developers and engineers
at PDI/Dreamworks who spent almost three years completing the film.
Directed by Andrew Adamson and Vicky Jenson, Shrek was produced by Aron
Warner, John H. Williams and Jeffrey Katzenberg. “It was a very
tough project, and for all the obvious reasons,” noted Warner.
“No one had ever done this before in terms of the number of characters,
the complexity of the environment, the number of effects that had to
be integrated, and the level of stylized human animation and facial
animation — the list goes on.”
Indeed, Shrek features what CG artists consider to be the Holy Grails
of CG animation — realistic, believable human characters; rich,
organic natural environments; mixtures of fluids (especially interacting
with characters); clothing with detailed textures and movement; and
realistic hair, fur and fire.
Warner noted that creating “realistic yet stylized” human
characters is one of the most important technical and artistic advances
in Shrek.
Visual effects supervisor Ken Bielenberg, who was the effects supervisor
on Antz reported that, “We were still in production on Antz when
Aron asked me to start development for Shrek. So, I overlapped for about
six months when I was finishing up Antz and getting Shrek off the ground.
As the visual effects supervisor, I had global responsibility for figuring
out how to achieve the directors’ and production designer’s
view for what the film should look like, and for getting that final
picture up on the screen.
“The big challenge at the beginning was that we didn’t really
know how to achieve the complexity in the background, especially the
complexity of doing human characters... and having a PG animated film
starring human characters,” he noted. “We had to somewhat
take it on faith that we would be successful at doing that, and the
success or failure of the project would to a great extent. hinge on
creating believable human characters that the audience would empathize
with.”
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Shrek
and Donkey
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He went on to stress
that, “There are so many things that go into creating believable
humans. The audience is not terribly forgiving of human characters because
everyone consciously or not is studying human behavior everyday. And
if we don’t get the major aspects correct, something is going to
feel wrong. One of the things we have to do is figure out what those
future items are and we had to find the level of stylization that would
be appropriate for the design of the film. It seems like it would be
obvious looking at the end product, but it wasn’t obvious at the
time what level stylization we would want. We weren’t trying to
make a photoreal movie, it was a stylized realism.”
According to Bielenberg, technically and creatively there were three
major challenges; the human characters, the complex environment and
then the traditional visual effects — “things like fire and
water and the elements,” he explained. “For human characters,
some of the challenges were rendering skin. Computers are really good
at rendering things like plastic and metal, as they love hard surfaces,
but to date they haven’t been as successful dealing with translucent
softer surfaces and we didn’t find real applicable computer graphics
research for rendering skin that we would use.”
“You have hundreds of thousands of blades of grass in a scene and millions
of leaves and an inordinate amount of data… So the rendering computation
times were much greater than they had been on Antz.” — Ken Bielenberg
Instead, the
team started off with studying papers that had been written for dermatology
and laser surgery. “They were very useful research in as far as
how skin reacts to light and as a mathematical model that we were then
able to adapt,” he said. “If the skin didn’t feel right
we could easily end up with characters that look like plastic mannequins.
So we spent quite a bit of time developing that and then also the degree
of detail that we would paint into the surfacing of the characters.
“At times there was a point at which we had actually gone too realistic
with Fiona and Farquaad and needed to pull them back in order for them
to work with Shrek and Donkey and with the overall style of the film,”
he added.
Other technical challenges with the characters were, the character animation
system and deformation, he reported. “The character set-up people
start and the characters are basically deformed from the inside out.
The character set-up people start to actually build a skeleton that
you never see, but then they built muscles on top of the skeleton. Then
there is layer of fat, skin and finally the clothing layer.
“The clothing was a big challenge as well,” he noted. “We
decided to do tight fitting clothing using our propietary tool layering
clothing is fairly difficult. We had to figure out getting the right
things to wrinkle as the characters move.”
For the flowing clothing like Fiona’s dress and the kilts that
the male characters wear the team decided to use Maya. “It’s
a really good cloth simulator and we worked that into our pipeline,”
reported Bielenberg. “And then hair was another thing that needed
significant development to figure out how would we move it. We wanted
to make sure animators had control over the hair, but then we didn’t
want to move each individual hair. So we had some aspects of the hair
which would be moved somewhat automatically based on the physics of
the motion and the kind of hair we put into the characters.”
