American Cinematographer - November 2004 - 74

All Aboard
A

rough

computer
animatic

depicts

the Hobo and the

Boy atop the
Polar

Express. To

lend the film's
action

a more

organic and
realistic feel,
operator Robert

Presley created
virtual

camera

with the

moves

help of a
computerized
camera-control
interface

developed by
Libra-head
inventor Nick

Phillips. This
interface
allowed
to

Presley
manipulate the

"virtual camera"

through digital
space, much as
he would in the

real world.

Additionally,
however, many of
the
camera

movingshots

-

including virtual
helicopter, crane
or dolly moves -
were key-frameanimated by
Imageworks'
"digital grips,"

eventually going to shoot the scene."
For example, if Zemeckis wanted to
pan from the Hobo to the Boy,
Hanks had to allow enough time for
the

camera move

in both his action

and

dialogue on the motion-capture
stage. "Its a timing issue: how long
does it take the camera to get from A
to B?" Presley relates. "We'd shoot
with videocameras on set to help
Bob focus on how each scene played
to a

everything

Using

Brian Doman.

consumer

handicams from

from
Circuit

a

City electronics store to Canon XL1
and

MiniDV

GL2

camcorders,

Burgess' team anticipated the
ments

of the virtual

camera

move¬
and shot

close-ups of the actors so that
Imageworks' animators could
impart every emotional nuance
through their digital characters.
"We'd actually be shooting right in
the middle of the actors to give Bob
a sense of where the camera might
be," Presley adds. "Because we didn't
wear sensors, we weren't captured in
the computer. The buzzword was
occlusion'
There

-

were

that

'volume' where
cameras, or

small

was not

'safe zones'
we

we'd put

crane so as

allowed.
in

could

the

place

a camera on a

not to

block the

We could also get
completely behind the mo-cap

capture cameras.

70 November 2004

further, different mo-cap "takes"

Says Burgess, "Early in my
I did lots of sports shooting
where I had 12 guys covering every¬
thing - that's what this experience

assembled

were

acter's

to create

each char¬

ideal

couldn't afford 10-12 operators on

performance. "Bob
like the first part of Take
1, the second part of Take 4, the third
part of Take 2 and the last part of
Take 12,'" Presley says. "Then the
Integration Department applied the

staff,

data

career,

like. I had

was
on

legitimate operators
principal cameras, but we

the

grabbed

I

so

around

-

anyone

standing

electricians, grips

-

scramble in with these Circuit

to

City

would say, 'I

shot

ence

which

performances from all these
angles."
The
proxy
videotaping
method was risky, however, as
Ralston points out: "If anyone even
tapped the support rig, it took up to

down

see

to

make

sure

the

different

an

hour

to

recalibrate."

Hobo but

played both the Boy and the
performed in two separate

weeks

scales, Zemeckis had to be certain

onto

the characters

naive

Hanks

appeared to be look¬
ing at one another. Burgess whipped
out an inclinometer normally used
to chart the sun's position and calcu¬
lated the characters' eyelines.
Once the capture phase ended
on a
given sequence, all of the mocap data - whether it was Hanks
playing against other actors, or in
this case, Hanks playing opposite
Hanks
was integrated into a
single scene. Complicating things
-

to one

it became

down

scenes

on

the mo-cap stage,

helped Bob gauge the perfor¬
mance and helped us
judge when to
start and stop a move based on the
facial expressions. Once the first
round of [mo-cap data and video
facial reference] came back, pared

like this, where

In

the characters. Meanwhile,

to

Editorial assembled the video refer¬

Bob could

videocams

virtual camera."

Alex Head and

if necessary."

cameras

to

three-dimensional file,

more

traditional;

we sat

actually shoot the scene."

As this process

stretched from

months, Burgess moved

to

other

projects. "We were a little
long things would
take as far as manufacturing shots,"
quips Burgess, noting that Presley
about how

remained
year.

on

the show for another

"Robert's a very patient man."

actors'

During the mo-cap phase, the
raw performance data was

translated into the computer in
master shots. But deciding how each

should be "shot" only
happened in what is traditionally
dubbed postproduction. "I'd call
scene
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