Walking With Dinosaurs
(continued from page 2)
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Science
meets imagination when creating the skin tones for the beasts.
© BBC/Discovery Channel.
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Skinning a Dino
Since no one will likely ever know what dinosaur skin looked like,
textures and colors for the CG dinosaur skin was derived through
a best scientific guess process of understanding the animals' habitats,
their lifestyle, whether they were carnivores or herbivores, and
body size as larger animals tend to have duller skin colors. But
Daren Horley, responsible for designing the dinosaurs' skin, despite
being fortunate enough to have a sample of an impression of actual
dinosaur skin sent to him, nonetheless found himself having to compromise
on a few things. "I discovered that to make the scale texture
[of dinosaur skin] show up on television, I had to make [the scales]
reasonably large," he says. "It became an informed compromise
between what was scientifically accurate and what looked right on-screen."
Once the BBC producers had approved the designs for the skin colors
a bump map was made. A bump map is a black and white 2D image that
the software will see as bumps or surface irregularities for shadow
and highlight detail. A color map was then painted over the bump
map and the resultant skin image wrapped around the 3D model, very
much like a tight-fitting suit.
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Splashes
were captured to bring authenticity to the million year old
environments. © BBC/Discovery Channel.
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How Do You Move a 70 Ton Dino? By Hand,
Naturally!
A very interesting fact that has emerged from how the FrameStore's
relatively small staff made 40 dinosaurs come to life was that animal
movements were largely the result of hand animation, an extremely
laborious and time-consuming process. But for this kind of show
Mike Milne and his animators saw early on that hand animation (moves
made manually on the computer as opposed to allowing the computer
to keyframe, or do the calculation automatically), was going to
have to be the way to go. "The only way we could achieve convincing
animation, the little wobbles here and there and the way the underlying
structures of the skin change with movement, was to animate the
dinos by hand," says Milne.
Since many of the backgrounds and foregrounds
were already filmed (along with the movements of trees, splashing
of water and other actual footage), FrameStore's animators had to
be doubly attentive to shot details. To again simplify the animation
process, the animators used low-res models with stick and ball skeletons
in much the way puppeteers manipulate a puppet's body parts to make
them move. This created extremely convincing animation, as the animators
were able to control the dinosaurs' movements 100% of the time,
a single frame at a time, thus maximizing their naturalness when
composited with the live-action footage.
The Real Deal
But were the dinos' movements going to be convincing enough? Since
no one actually knew how a T-Rex's forelimbs would move,
how would the animators make it look natural on-screen? True to
the remarkable attention to details given this production, a decision
was made early on to use, among other things, live elephants to
"model" dinosaur movement for the animators to study and
use.
