Desktop Meets Stop-Motion
How digital tools bring The PJs to life.By Richard Young
Viewers of The PJs, the gritty animated series that airs on the Fox Network, are regularly treated to the antics of Thurgood Stubbs, a gruff building superintendent, his family, and his tenants in the Hilton-Jacobs Projects. The characters have been brought to life by the brilliance of an incredible team of creative minds that includes Ron Howard (Backdraft, Cocoon, etc.), Brian Glazer (Splash, The Burbs, Real Genius), Steve Tompkins (The Simpsons), Larry Wilhome (The Jamie Foxx Show, In Living Color), Will Vinton Studios (California Raisins, M&Ms, the Nissan Toys commercials, etc.), and comedian Eddie Murphy.
In fact, it was Murphy who dreamed up The PJs while watching Thunderbirds-the
60s television show that starred marionettes as swashbuckling, space-faring
heroes. For his puppet show ("PJs" originally referred to Punch and Judy),
Murphy wanted to draw on edgier material-life in housing projects. To give
the show a unique look, stop-motion legend Will Vinton and his crew at
Will Vinton Studios in Portland, OR, were brought on board. Murphy supplied
the voice of Thurgood Stubbs.
The PJs first aired midway through the 1999 season. It boasted some 10 million viewers per week, earned an Emmy nomination, and has spawned a sibling with the upcoming show Gary & Mike. The latter, as with the The PJs, is foamation-a modern variation on claymation, a technique in which sculpted figures made out of clay hang on armatures and are shot one frame at a time. Foamation, as its name implies, uses characters built not of clay but of foam latex over metal armatures with sockets and interchangeable plastic heads. In addition, the directors of the show attempt to keep as much of the show in the realm of the foam miniature, so effects such as flowing liquid, sweat, and the characters' facial movements are produced using practical effects on the stop-motion stage. Facial moves are created with replacement parts (lips, eyes, etc.), not in 3D with morph targets (see Figure 1). Liquids are simulated with epoxy replacements, while sweat beads are often glycerin drops. To create motion blur, "go-motion" blur is sometimes used (go-motion is the physical movement of the rig object as the film is exposed).
These techniques yield realistic textures, lighting, and depth. But there's a downside-the stop-motion process requires painstaking attention to detail. A single 22-minute episode takes 28 weeks to produce (!) at a cost of $1.2 million. By contrast, a typical 2D Saturday morning cartoon episode runs from $50,000 to $100,000 to create.
But that's not what we're here to talk about. In the fast-paced environment
of weekly television, Will Vinton Studios relies on digital tools to speed
the process and boost the impact of each prime time episode of The PJs.
We spoke with Steve Bailey, one of the digital effects supervisors at the
studio, to learn more about how they're using digital tools to support
and enhance the stop-motion process and crank out 22 weeks' worth of episodes
in time to meet their on-air deadlines and deliver what a spokesperson
for Vinton Studios has described as "a quality you don't see in prime time
Putting the show togetherBailey: "Three to four weeks into preproduction, an animatic is created from the storyboards, with scratch audio if there's a talent scheduling conflict. Then there's a breakdown meeting. The director leads the meeting of key departments, including art, scheduling, stage, motion control, lighting, storyboard, and post departments. This is when the edit is locked for production."
"The stop-motion action is filmed at 24fps, then telecined with 3:2 pulldown to Digital Betacam (D-Beta) tape. An Avid Film Composer is used to produce a rough cut, and timecode information is fed to a DPS Hollywood system ( to capture uncompressed D-1 resolution files from the original D-Beta tape. Files are sent on to a Discreet flint or flame system, or to NT/Alpha workstations where 3:2 pulldown is removed with eyeon Digital Fusion . The flame and NewTek LightWave render farm is shared, so scheduling is a factor. CG material, about 5 percent to 15 percent of each show, is sent back to the Avid on D-Beta tape so the director can see it cut back into the show and give it approval."
"We have two full-time Avids at the shooting stage. We use that model because we work at 24fps, but we need to go to 30fps in the final online. That model is designed to suck in 30fps (our film transfers), treat it like 24fps, and output a 30fps EDL for the online."
"When removing and reading 3:2 pulldown, depending on where the pulldown
is removed, a frame can get lost and the total frame count becomes off
by one. We use 15-frame handles on every shot to ensure that problems like
this don't force a revision. We also try to make sure every first frame
from the Avid EDL is an 'AA' frame. This ensures proper pull-up and maintains
Routine fixesFixes account for about 90 percent of the work done by the effects team. Paint work for character position rig removal, light pop removal (more on this later), and smudge touch-ups are routine, though scripts also require effects that can't be created in stop-motion animation. Other examples of paint fixes include smudges on character faces and stray object removal. Paint touch-ups are most often routed to the flame because it provides realtime feedback. If a system isn't available, the job may be done with rotosplines in Digital Fusion.
Rig removal is needed for action scenes with flying objects. Rigs are used to hold characters in place when they are jumping or flying in the air. A clean pass of the scene without the character is shot with a motion control rig to make rig removal easier.
A common problem in stop-motion animation is called "light pop." Light pops can occur when a shot takes longer than a day and overnight power fluctuations cause slight shifts in lighting. Bailey explains, "Sometimes, in a single frame, the light value will change and then go back. That frame needs to be adjusted. A brightness/contrast/color adjustment usually fixes the pop. Frames can also be sampled from before and after the pop and blended to smooth over it, but this only works if there's little or no motion in the frame, which is not very often."
Bailey continues, "If an animator resumes a shot the next morning after
leaving it the evening before, sometimes the lighting values will have
shifted slightly. This can be caused by an accidental bump on the set,
or 'dirty power' in the industrial neighborhood where the stage is located.
In this instance, a whole section of the shot will need to be tonally corrected
to match the previous section."
Enhancing effectsAbout 40 percent of the scenes are shot against a bluescreen or greenscreen because the sets are small. Outdoor shots use bluescreen, which at Vinton Studios is the larger screen. Bailey asks for green if it's a nighttime shot because Vinton Studios often uses blue lights. "We use both Ultimatte (with Fusion/flame) and the Fusion UltraKeyer. And obviously we use the internal flint/flame keyers. All have advantages and disadvantages depending on the attributes of the given footage and the experience of the given user."
A common outdoors shot involves cars. If a character is driving a car,
the scene is shot against a bluescreen and comped against a fly-through
of a digital camera through a digital city (see Figure 2). If stage
real estate isn't available, a separate pass may be filmed and composited
later. A lot of activity occurs on the roof of the projects. The set may
use a high-rez 3D render as a backdrop. Sometimes part of the shot might
require visible action in the backdrop. There may be a car turning a corner
toward the building over the shoulder of the character. If shot over a
bluescreen, the edge of the roof is part of the practical shot (see Figure
More than fixesAncillary effects include fire, smoke, steam, gun muzzle flashes, sprays of water, and crowds of low-rez generic characters. Set extensions (for example, digital cityscapes and other outdoor scenes), as well as high-rez printed backdrops are created in NewTek LightWave. Any camera shot on a stop-motion set at Vinton Studios requires a motion control rig. Depending on the rig, it will generate data that can be translated into a LightWave camera move. This is done with varying degrees of success. 3D scenes are composited in Digital Fusion using depth maps and blurred backgrounds for perspective.
Smoke and fire effects had been done in LightWave with volumetric and shader tricks, which lent a cartoon look to the shot. The team transitioned to natural elements that they shot themselves. They find that motion-tracking real fire and real smoke onto the scene makes the effect look like it was built into the shot. Occasionally, though, an element can't be found and the effect needs to be built from scratch (see Figure 4).
Many smoke elements don't behave like smoke when tracked because an
entire smoke plume doesn't move when the object moves. To get smooth trails
of smoke that generate from an object, Bailey uses 5D's Smoke filter (
Fusion.htm ), which is available for both Digital Fusion and flame.
Typically, cigarette smoke is generated in Digital Fusion. Pixels at the
top of the cigarette are tracked, but if the cigarette moves quickly, you
get discreet puffs of smoke, which can be small dots if the motion is very
fast. This is because the NT version of the plug-in doesn't do between-frame
subsampling-it launches a certain number of particles in each frame. Bailey
uses a Digital Fusion expression, a script to modify parameter behavior,
which looks to see if the cigarette has moved too far in the frame. If
it has, the smoke emitter is suppressed for that frame. He uses the tracker
to generate a path and that path becomes the smoke emitter source.
In Figure 5, from the "Go-Cart" episode of Season Two, the go-cart wasn't moving, but sitting throughout the scene-movement down the ramp was animated by replacing the ramp. The scene was keyed and a camera move was generated manually in LightWave to match the go-cart's movement because there was no camera path data. Finally, certain sections of the ramp were treated with motion blur to enhance the effect. This episode is one of Bailey's favorites because of the larger role played by the desktop effects team.
Bailey's staff tries make everything in an episode look as if it's in
front of the camera instead of a layer pasted on top. Shows have a variety
of flavors that reflect the styles of each director, and computer graphics
are sometimes used to push a show in a certain direction if there's time.
Still, the nature of the work being handled by Bailey's staff has evolved
along with the look of the show. After the 2000 season, the team will have
produced 34 shows and have a good feel for which tools are best for each
job. The producers avoid both overly cartoon-like and hyperrealistic looks.
Familiarity with production enables CG to pick the right element for the
right shot to help bring a prime time series featuring tradi-tional animation
Images courtesy of Will Vinton Studios and Jim Lommasson.
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