Brian (digibri) wrote,

Tool Time at Pixar

Time at Pixar

This is a teriffic article describing a new software tool created to help
with the development of The Incredibles at Pixar.


By Ellen Wolff
Nov 1, 2004 12:00 PM
Sketching The Incredibles
If you were in the Pixar screening room where director Brad Bird regularly
reviewed images for The Incredibles, you would have seen a cool, new tool in
action - the Review Sketch tool. This tool literally allowed Bird to draw on
top of a projected image using a digitizing pen. The drawings were then
accessible online by other members of his team.

Pixar's proprietary vector-based Sketch Review tool, developed during
production of The Incredibles, allowed director Brad Bird to draw animation
corrections on top of a projected image using a digitizing pen. The
Incredibles marks Pixar's first feature with a "human" cast.

"It's a classic animation thing to want to put a clear sheet over an image
and draw on top of it," says Dr. Michael Johnson of the Studio Tools group
and a software lead on The Incredibles. "People here have even used
dry-erase markers on their CRTs. We've always talked about wanting to sketch
on top of stuff, but for a variety of technical reasons it's been hard to

That changed when The Incredibles - Brad Bird's 3D-CG feature debut - was
underway. Bird was familiar with the CG techniques used in his largely
traditionally animated Iron Giant, but the first instinct of this acclaimed
2D animator is to communicate by sketching.

"Brad's always giving a pen to someone and saying, 'Well, draw it,'" says

Karon Weber, Pixar's user interface designer, soon noticed Bird's
preference. "Karon observed that what Brad was doing in reviews was to have
somebody put an image on a monitor that was, in turn, projected onto a white
board. Brad would draw on top of the projection on the white board, and then
someone would take a digital picture of that drawing to capture it," says
Johnson. This cumbersome process led Weber to propose creating a digital
sketch tool for Bird: one that would leverage the capabilities of Wacom's
Cintiq digitizing tablet and pen.

Bird was open to the idea, according to Johnson. "For people like Brad who
are purely on the creative side, a lot of the technology we have available
at Pixar can seem pretty astonishing," says Johnson. "If you come from more
traditional animation, you don't think of people being able to go out and
invent a new kind of pencil, or give you a new kind of acetate that lets you
erase underneath it."

Pixar's technical gurus tackled the challenge using the Cintiq as a hardware
gateway. Weber and fellow designers Brendan Donohoe and Max Drukman
developed the user interface, and Johnson provided sketching code that he'd
been writing for use on the Macintosh OS X platform. Weber also volunteered
the services of her summer intern Antoine McNamara, who was aided by
Johnson's intern Josh Anon. After a summer of brainstorming, McNamara put
together the completed application.

The Review Sketch tool, which resides on all the Macs at Pixar, contains
features that addressed Bird's style of working. The director could draw on
an image, and then play it back with the image moving underneath his
drawing. A slider let him choose the width of the anti-aliased line.

"Most people dial it way down and have a very fine line," notes Johnson.
"Brad would use a two- or three-pixel line as his hard line."

When Bird put the pen down, the system would automatically record a
"snapshot" of what he had drawn. "We also added ghosting so that you could
do multiple drawings and see the other drawings as well, though I don't
think that got used as much as we would have liked," says Johnson.

A key feature of the tool is its eraser. "This is a vector-based tool with a
raster erase," says Johnson. "You can scale an image up or down, and when
you want to erase, you turn the pen over and it erases. It feels very
natural. Whenever I give a demo of this tool to artists and show them that
feature, they immediately say 'I want one.' It is super simple to remove
something easily, but really hard to remove the whole drawing by mistake.
You'd have to erase the whole thing. It's a big, fat, 30-pixel eraser
because we found that people want a fat eraser no matter how fine their
lines are. They tend to erase whole big chunks. The underlying software
knows when you put each stroke down. Erasures are actually saved as strokes,
so we have the entire drawing history.

Using Pixar's Review Sketch tool, an animator can draw on an image, and
then play the scene with the image moving underneath the drawing. Other
features of the tool include a slider for choosing the width of the
anti-aliased line, ghosting, and a raster eraser. The tool's drawings are
stored on Pixar's intranet, which allows for immediate accessibility.
"What makes this tool really slick is how it's integrated into our screening
rooms. We have this big expensive switcher in our screening rooms - you can
route this or that computer into a screening room. We made the observation
early on that we could turn a computer monitor into NTSC, because what the
animators were doing at their desktops was essentially video rez, and then
put that into a DV converter. On the Mac, I can get a DV stream in realtime,
coming in over [Apple's] FireWire. Alex Stahl in our AV group made a huge
contribution when he did some magic with the switcher and routed everything
that goes to the projector through this DV conversion stream. We run this
tool on the Mac OS X server, which we rackmount with all the video
equipment. When Brad sat in front of the Cintiq in the screening room, what
showed up onscreen was the video stream that he was drawing on top of. It
made the whole thing seamless."

Even though the system reduced images to DV resolution, they didn't lose
much information. "People might have something up in Maya or [Pixar's] Menv
that they wanted to be able to draw on top of," says Johnson. "Things look
softer when they're turned into DV, but at the stage they were using it,
color and lighting weren't issues. The artist could sit with the director
and the Cintiq, and when the director said 'Can you zoom in on that?' they
could. Then they could draw on it."

Perhaps most useful - from the artist's perspective - was that the end
product of the session wasn't just a digital snapshot of a corrected image
on a whiteboard. Because files of review sessions resided on Pixar's web
server, artists could go the studio's intranet and access what they needed
in order to proceed.

"It's organized along three axes: what kind of review was it; what review
room it happened in; and when it happened," says Johnson. "We have the
background image, the foreground image, and the composited image. Then we
have the drawing made at a standard camera size and the RGBA drawing of it.
The artist can bring up a frame that's in our 3D system, then bring up the
director's drawing and layer it right on top. It's not a terribly
complicated program that puts heavy demands on a computer. Anybody's Mac -
even a little iBook - is perfectly fine for running this."

Although this tool was designed to address Brad Bird's penchant for drawing,
word of its development traveled fast. The people working on Finding Nemo,
which was quite far along at the time, wanted a system installed in their
screening room. Nemo's production designer Ralph Eggleston pushed especially
hard for this. He'd grown weary of using a laser pointer to indicate the
changes he wanted made in the film's many undersea simulation shots, and
then having to wait while assistants wrote copious notes. With this new tool
in hand, Eggleston could view an image filled with schools of fish and
simply cross out the fish he wanted to delete.

"Only at Pixar would you be allowed to be that anal retentive," says
Johnson. "And I mean that in a good sense!"

The studio's artists have become believers. When Eggleston signed on to The
Incredibles, he asked for yet another Review Sketch tool to be installed in
what Pixar call "the layout lounge."

Eggleston may not have actually referred to it by its proper name, however,
because some people call it the Madden tool after NFL TV analyst John

"There's actually a tool at ILM called the Madden tool, which is why we have
the more generic name," says Johnson.

Early on, Karon Weber proposed naming the tool after a pioneering
interactive-TV show called Winky Dink and You. The mid-1950s CBS show
encouraged children to buy a clear-plastic screen that fit over their TV
screens on which they could draw lines that would augment the animated
action. Millions of kits were sold, and kids dutifully drew the bridges,
ropes, and ladders through which Winky Dink escaped peril.

Johnson had a strong reaction to Weber's suggestion. "I said 'I am not
supporting a tool called Winky Dink!'" he says.

By any name, the tool has permitted the artist's hand to influence the
computer animation process in an interesting, gestural way. Artists like
Brad Bird can add touches that promise to stretch 3D-CG beyond its tendency
to be photorealistic. Given that The Incredibles is Pixar's first film with
a human cast - in very comic poses - it isn't surprising that this project
inspired the development of a sketch tool.

Because Pixar's Review Sketch tool is process software that operates in the
background, its influences can only be inferred. But all of these interim
sketches still remain on Pixar's intranet. It will be interesting to see if
any ever make their way into books or as an extra on the DVD.

"All those drawings are still sitting there on the same website," says
Johnson. "It's fun to spelunk through it. Occasionally, you'll even see a
hangman game!

"It's a scalpel, not a Swiss Army Knife," says Johnson. "But it has a really
sharp blade with a really good handle on it. At the end of the day, it's a
very simple thing, but it's executed very well."
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