Some info on Disney's CAPS system
Collin Ong
Here's some more info on Disney's "secret" digital animation system.
From Computer Graphics World, July 1994. (reproduced without
permission, but certainly without profit) I just thought it might be
interesting for those on rec.arts.animation and rec.arts.anime.
DISNEY LETS CAPS OUT OF THE BAG
by Barbara Robertson (CGW's West Coast senior editor)
Housed in an unpretentious, one-story office building in an industrial
park in Glendale. California, about 10 minutes away from the Burbank
airport, is one of the most creative and successful groups in
''Hollywood"--Walt Disney Feature Animation. Here, in this very
low-profile location, Disney artists have created two of the
highest-profile and most profitable animated features ever: Beauty and the
Beast and Aladdin.
In the lobby, a tidy wall display steps a viewer through the process of
making an animated film at Disney. In the display, you see a page from
the movie script for Beauty and the Beast. A handwritten exposure sheet
details the mechanics of a scene, frame by frame, including camera moves.
Pencil sketches of the Beast, a color model that shows a sample painted
Beast with all his colors carefully labeled, and beautiful hand-painted
cels that show the pencil sketches inked and colored complete the process.
It's educational. But it's not accurate. Not any more, and not, as a
matter of fact, for Beauty and the Beast, the second feature film ever
made to have every frame passed through a computer. Disney's Rescuers Down
Under was the first.
Make no mistake, Disney feature animations are still created by hand--the
characters are sketched, frame by frame, in pencil, by animators; and
backgrounds are painted. But since 1989, nearly everything else happens on
a computer.
Once a pencil test of the animation and layout for a new film are
approved, the exposure sheet becomes digital; the inking and painting are
done by artists coloring pencil sketches scanned into a computer;
backgrounds, middle grounds, foregrounds, and other painted layers are
scanned into the computer for digital compositing and special effects; and
digital files are sent to a film recorder to create the movie. The only
cels now painted by hand are those destined for gallery sales.
[Picture caption: In this establishing multiplane shot for The Lion King,
Disney artists used CAPS to fly a "digital camera" behind the bird, to
follow it as it soars over dozens of layers of animals racing toward the
rock.]
The system these artists work with for this "back end" of a production is
called CAPS (Computer Animation and Production System). Engineers at
Disney and at Pixar (Richmond, CA) began creating it in 1987, and they
haven't stopped adding features and refining it since--with Disney largely
responsible for the infrastructure and Pixar for the graphics and user
interface. It's been used for four features--Rescuers Down Under, Beauty,
Aladdin, and the recently released l.ion King. Work has begun on a fifth,
Pochontes. Although in March 1992, 10 people, seven from Disney Feature
Animation and three from Pixar, received Academy Awards for scientific and
technical achievement for their roles in developing Disney's CAPS, Disney
remained very protective of the system. Until recently people outside
Disney had seen it. We're the first people from the press to be invited
inside.
First stop, Scene Planning, first door on the right. "Before you get to
this part of the building, it's Disney of the 1930s," says Paul Yanover,
manager of CAPS, who will guide us through the digital side of Disney.
The people at Disney emphasize that CAPS is not just technology; it's the
process of making the film, and it's the people. They're right. But the
technology is pretty darn impressive. Consider: Movies are measured in
feet. about 7200 feet per movie (16 frames per foot, 24 frames per second,
80 minutes). The artists work with images at 2K resolution, 12 bits per
color channel (plus alpha). They can choose from 69 billion colors.
"There are dozens and dozens of graphical operations," says Tom Hahn of
Pixar, who has been working with CAPS for the past eight years. "It can do
virtually all the useful 2D operations we know about for films."
The artists produce, and the system manages, 5 terabytes of data per film,
more or less (the equivalent of 5 million 1.2MB floppy disks)--more than 2
million image files per film. They're producing finished work at a rate of
11,000 frame levels per week--300 feet (or more) of composited, final
scenes per week. CAPS is totally integrated into the production process;
all the departments--Scene Planning, Animation Check, Scanning, Color
Model, Ink and Paint, Compositing-- have equal access to all the exposure
sheet data for any scene moving through production. Although, of course,
not everyone can change an image, anyone can play, on screen, any scene in
the pipeline frame by frame or as a film loop--in its current state or in
any incarnation in time.
[Picture caption: Here, scared, little Simba has just escaped the herd of
wildebeests. The dust cloud, a CAPS special effect called "turbulence," is
created automatically when the scene is composited.]
[Picture caption: In this scene from the Lion King, Disney artists chose a
CAPS special effect to emulate a familiar live-action optical effect
called "rack focus." At first, we see the foreground ants in focus; then
the focus changes to reveal the zebras in the background. Without CAPS,
artists would have to draw and paint individual pieces of art for each
stage of the blurring on all the layers through the entire scene. Now,
they add an instruction to the exposure sheet, and the blurring happens
automatically when the scene is composited.]
The graphics capability is amazing, the data management astounding. It's
continually being rewritten in response to production requirements of the
most massive ongoing production of feature animation at the highest
quality. It's a remarkable system.
"I could never imagine making movies without it today," says Peter
Schneider, president of Disney Feature Animation. "With the number of
things we're doing and the speed demands, we could not have made these
movies traditionally and had the same kind of quality level.
"Has it made it easier? I don't know," he continues. "It's made it more
fun. It's made it more fun because you can do so much. As an artist, you
can conceive of something and go do it." Ann Tucker, supervisor, Scene
Planning, who worked on Disney films using traditional methods before
CAPS, puts it succinctly: "Now, I'm free."
In Scene Planning, the mechanics of a scene--the camera moves--are
calculated for each drawing and painted layer in each frame. A scene might
be as short as 1 or 2 feet (16 to 32 frames), as long as 40 feet-- even
longer. This department is the starting point for CAPS.
CAPS is a dual-monitor system. One monitor (usually the left) displays the
exposure sheet with user interface icons, buttons, etc., above. The second
monitor is used to play the scene. In every department, you see basically
the same thing, although the icons and buttons change to accommodate
different functions; and rows and columns in the exposure sheet expand and
compress to display the data most needed by a department.
Scene planners work with low-resolution scans of pencil drawings and start
with handwritten exposure sheets that they enter into the computer. This
digital exposure sheet becomes the lifeblood of the production process. It
looks something like a spreadsheet with rows and columns for frames and
levels; it eventually contains all the data for a scene.
On screen, a film loop of a black and white pencil test is playing. "This
is a simple multiplane scene," says Tucker, who realizes what she's said,
and laughs. "There used to be no way you could put the words 'simple' and
'multiplane' together. There are seven pieces of art here. That was the
limit conventionally." Now there are no limits. It's not unusual for a
scene to have from 50 to 100 layers. Artists use multiplane shots to give
a scene dimensionality, to have characters move through the layers as if
they were moving through an environment. This added depth and richness is
one of the most noticeable changes in the look of Disney movies since
CAPS.
"In Little Mermaid there are three multiplane shots because that's all we
could afford and all we could really manipulate. In The Lion King there
are hundreds," says Schneider. Once the cleaned-up pencil test is
approved, it's sent-- digital film loop and exposure sheet along with the
original pencil sketches and other notes in the scene bundle-- to the
Animation Check department. Here, supervisor Janet Bruce checks the
animated pencil test against the original layout and looks for mistakes.
On screen, the young lion, Simba, runs through a cloud of dust raised by a
herd of wildebeests, with Bruce controlling the frame rate. Simba goes
behind a rock. Oops, his shadow stays in the scene. To remove the shadow,
Bruce deletes that level from the exposure sheet and physically removes
the drawing from the scene bundle. Second scene: Nala, the lioness and
Simba's girlfriend, comes flying over a log after Pumbaa the warthog. In
this scene, there are enough layers to create a confusing mesh of pencil
lines, so Bruce isolates each. Then, she checks each frame to see that
Nala's shadow travels properly over the log and fits neatly into a crease
of land, that her feet land f on the ground when they should. "We're sort
of like the dress rehearsal," says Bruce. When the scene leaves this
department, the animation (pencil drawings) and the backgrounds (layouts,
now painted) are ready for final scanning at high resolution.
The motion-controlled scanner was built for Disney using specifications
from the CAPS engineers. It's controlled by data in the exposure sheet
which sets the camera position and resolution for each drawing in the
animation and each painted layer. Various sections of one painted
background might be scanned at different resolutions to accommodate camera
moves yet efficiently manage data requirements. For example, as the camera
zooms in on the stained glass window in the opening scene of Beauty and
the Beast, the window is scanned at higher resolutions. "I scan exactly
what's needed as it's needed and only that," says Robyn Roberts,
supervisor of Scanning.
The CAPS software then automatically seams together scanned sections so
that, for example, you might see a scene where the camera swoops across
one seamless background as it follows the main character running through a
scene, even though the different parts of the background were, in fact,
scanned separately. Next stop, Color Model. It's in this department that
you really see the power of the graphics engine. The output from this
department is the color scheme for all the characters in a scene and the
settings for all the CAPS effects. "[The words] 'color model' really
understate what we do," says Randy Fullmer, artistic coordinator on The
Lion King "In Color Model, we capture what you see on a frame."
They start by running the pencil test (on the computer screen) to see a
character within its layered environment, then pick a keyframe to color.
As they color the character, they're interactively designing a color
palette.
"We used to have a limited number of palettes for a film--about
nine--although in Mermaid we had a lot," says Karen Commella, supervisor,
Color Model. "Now we can have one palette per scene." For this scene, the
scene where Nala hunts Pumbaa, they decide to blur the grass in the
foreground to give the scene more depth. (The grass was scanned as a
separate layer.) The exposure sheet now includes an instruction for that
layer that progressively blurs it, from zero to 15, over a series of
frames. The blurring happens automatically when the scene is
composited--as do all the special effects. "At first, the system did way
more things than we could use," says Fullmer. "Then we started asking for
more."
In The Lion King, for example, the artists are making particular use of a
feature they call "turbulence." "We based 'turbulence' on work done by
Ken Perlin," says Pixar's Hahn. "I decided to put it in and see if anyone
used it. They were in the middle of production then, but now you see it in
most of the effects scenes in Lion King" You see it, for example, in
waterfalls, dust clouds, and jungle fog. Other effects in The Lion King:
ripples and reflections in water, backlighting, progressive color changes,
camera effects that simulate a live-action camera. "The directors on Lion
King wanted characters to go out of focus and get darker as the shape
comes toward you," says Fullmer. With CAPS, the directors can now
describe a look and watch as the Color Model artists create and change it
interactively. To help speed compositing, the system knows which layers
have been changed and updates only those layers.
"This is a very collaborative art," says Commella. "It's a very exciting room."
PAINTING--AND INKING
Once the color model is set, the palette for a scene created, with colors
for each character defined, the scanned pencil drawings can be inked and
painted.
In the Ink and Paint department, the user interface changes radically--the
exposure sheet area turns into a digital equivalent of an acetate cel, the
user interface area is filled with colors and Mickey Mouse icons to select
an inking plane (to color the lines) or a painting plane (to fill areas
with color). Artists can change the colors of inks before or after a
character is painted.
"I like to see the character's color when I'm inking, so I prefer to paint
first," says Carmen Sanderson, painter, who joined Disney September 17,
1945, she states proudly, right out of high school. Sanderson demonstrates
some of the paint system features--quick selection of colors from the
palette, a bounding box for easy fills of small areas, erasers. Then she
switches to inking.
In the 1950s, Disney began using a custom Xerox copier/camera to put
pencil drawings onto acetate. The resulting black lines were costly and
difficult to change to colored lines. It dramatically affected the look of
Disney animations.
[Side bar: A terrifed Pumbaa-- from storyboard sketch to final composite.
Second image: the "ruff" pencil test. Once the pencil test has been
scanned into CAPS, Scene Planning palys digital film loops of these hand
drawings and works out the mechanics of the scene. Third image: the
"cleaned up" pencil drawing. Low-res scans of these drawings are used to
check entire scenes in Animation Check. Once approved, the hand drawings,
scanned at high resolution, move to Color Model, then Ink and Paint.
Bottom image: the final inked and painted, composited scene. The
foreground grass, a painted (and scanned) layer, was blurred during
compositing.]
"Before CAPS, we could only ink the most important characters," says
Hortensia Casagran, supervisor, Ink and Paint. "Now, some characters have
10 to 12 inks."
Further, the lines can be blurred; colors can be blended. "It's such a
great look," says Gretchen Albrecht, manager. "It gives a softness, a
roundness to the characters." The obvious and first use was for makeup
(Belle's rosy cheeks in Beauty and the Beast); now, it's being used on
nose bridges, legs, ears. "It's an extra step, but it's worth it."
All the departments have quotas to meet, feet of film to push down the
pipeline. Keeping the assembly line fed is a constant balancing act. "We
want it to be as fast to scan as to paint as to composite as to film-
record," says David Coons, who has been working at Disney on the system
since its early days. To help speed the inking and painting process, a
special mode now allows six painters to work on the same scene
simultaneously.
THE FINAL CHECK
Once the scene is inked and painted, it can be composited and readied for
a final check. The compositing is a batch process that's queue-driven
using a network of cooperating machines. When a composite is ready, it's
fed back to the people who need it in the departments. Final composites go
to the Final Check department.
Here, final checker Teri MacDonald views a composite of the scene, 40
frames at a time--at frame rate--in full color and final resolution. She
toggles back and forth through the scene looking for mistakes. She finds
one. "Look, Nala didn't get inked correctly," she points out.
Before, MacDonald had to do everything by hand, organize the backgrounds,
the cels, then flip through them looking for mistakes. It's hard to
imagine.
The original goal for CAPS was to keep the Disney animation process,
streamline it, and bring back the quality that had been lost after 1950.
"Disney reached its low point in animation 10 years ago with the release
of Black Cauldron," says Schneider. "By and large, no one thought there
was any value in animation." To create the movies of the '30s and '40s by
hand at Disney would have been tremendously expensive, and the little new
technology introduced in the production process, the Xerox machine, had
actually hurt the image quality. If Disney Feature Animation were ever to
reach its past glory, something had to change.
"It was really Roy Disney who, in the takeover, ended up with the
animation division," says Schneider. "He said to Michael [Eisner] and
Jeffrey [Katzenberg], 'Wait a minute, go off and fix live action. But the
animation division is very special. Don't touch it.' " Disney and
Schneider pushed through a proposal for the CAPS system, a proposal
meticulously developed (and cost-justified) by Lem Davis and other Disney
engineers earlier, but not acted upon. Then, Disney contracted with Pixar
and began working with Alvy Ray Smith on system specifications. The
development of CAPS, the system which would give artists in the '90s the
tools to create looks as rich, even richer, than the feature animations of
the '30s and '40s, was underway.
In 1989 the CAPS team created one scene, one of the last scenes from The
Little Mermaid (Triton and the Merpeople, waving to the newlyweds). They
expected to work next on a small feature. Instead, Schneider told them
they'd move straight into full production on Rescuers Down Under. It was a
bold move.
[Picture caption: With CAPS, Disney artists regained the ability to have
various colors of ink on characters, and now they might use as many as 10
or 12 inks on a main character-- as well as special color-blending and
line-blurring techniques]
"Now that," says Ed Catmull, president of Pixar, "can make people focus."
"The system wasn't tested," adds Hahn. "It wasn't really finished."
"If you look back on it, it was a stupid decision we made, because what if
it hadn't really worked?" says Schneider. "It was very exciting. It was
really pioneering. But it was on the edge the entire way. We were all here
24 hours a day for weeks."
Would Schneider do it again? "Yeah," he says. "Because I think if you
don't, nothing gets done."
What the CAPS team has done is given Disney artists tools that have
changed the look of the films-- forever. "I think the original objective
was to replicate what we had, to not lose quality," says Schneider. "We
always knew it could restore lots of things, colored lines, airbrush, you
know, the simple things. We've gone one step further. If you look at
Beauty and the Beast, at Rescuers Down Under, although they were
significant steps forward, they were about replicating, about trying to
get back some of the artistic techniques from the '30s and '40s. When you
look at Aladdin and The Lion King you realize we have surpassed
technically--I'll never say moviewise, that's for someone else to say--but
technically, we have surpassed the kinds of things that were done back
then, which is very, very satisfying."
What's next? The graphics system has been ported from the proprietary
Pixar Image Computers onto general-purpose workstations. The port took
nearly two years, but it's done. "I have it running on several platforms,"
says Yanover. "We don't want it to be tied to any platform. We want it to
be open."
We can expect this new CAPS to include new features. Already, Hahn and his
team have added live-action special effects in response to a request from
Disney's Buena Vista division. The effects have been used in Nightmare
Before Christmas, Dave, and other movies.
And, we can expect to see a tighter linking between CAPS and 3D graphics.
Now, 3D scenes are created apart from the traditional animation process, a
process CAPS diligently emulates. Basically, rendered 3D scenes are
composited with the 2D scenes, which means there's no way for the people
in Animation Check to participate in the process.
"There's a lot of work going on in this area," says Yanover. "We're
working on a proprietary system with next-generation 3D graphics and
integrating that system with CAPS."
The switch to workstations is timed to take place with the move to a new,
flashier building in December-- the fulfillment of a promise to Feature
Animation from Michael Eisner after the success of Beauty and the Beast.
One of the Disney engineers proudly notes that you will be able to see the
word "Animation" on the new building from the freeway.
The move also allows the engineers to install a new, faster network, to
think about new tools--and new parts of the process that might benefit
from digital media. "There will be a lot of new functions and tools to
provide artists new ways to do things," says Mark Kimball, who has been
largely responsible for the system logistics. "I believe the new tools
will have as much impact in the future as CAPS has had up until now."
Adds Schneider: "I look at CAPS as a first step, sort of the engine that
allows us to do everything we do filmmaking-wise, whether it's the rack
focus, the 360-degree camera shot, the wildebeests, the dust, the multiple
images.
"If you give artists challenging tools, they will use them and will push
them further," he adds. "They just keep pushing until someone says 'stop.'
And by and large, we don't ever say stop."
You don't?
"No. Why? As long as it's important to telling the tale in the movie, to
telling the story, it's important to do," says Schneider.
Clearly, they pulled no stops with CAPS. CGW
--
Collin K. Ong
col...@mcd.fm.intel.com (post reply header is incorrect)
[My opinions only]