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. 
 
 

Figure 1-Facial animation is done in stop-motion using replacement mouths, eyes, and eyebrows. Mouths are set up by a soundtrack reader who figures out which lips go with which frames. Sometimes lips and other parts appear in the frame and need to be painted out. 

VITAL STATISTICS 

Project

-The PJs, the first prime time stop-motion animated series. Its second season began airing in Mar. '00. 

Producers

-Imagine Television, Eddie Murphy Productions, and Will Vinton Studios in association with Touchstone Television. 

Number of People Involved

- About 120 total (in Portland, OR). 
- 32 stop-motion animators, with 5 assigned to each episode.
- Six concurrent directors. 
- Two desktop CG artists; one flint artist, one flame artist. 

Production Details
- 40 percent of CG shots are bluescreen. 
- About 80 percent of CG shots are fixes-most of those are done in flint and flame. 
- CG material involved in about 5 percent to 15 percent of each show. 
- 28 weeks to produce each show, 12 of which are for stop-motion.
- About two minutes produced weekly on each of six episode productions. 
- 150 puppets; number of each varies (30 Thurgood puppets). The main character is 13 inches tall. 
- 50-55 sets up at one given time (there are many other sets because they keep changing). 

Budget

$1.2 million an episode. 

Applications Used

Adobe Photoshop 4, eyeon Digital Fusion 2.5, 5D Monsters effects boxes, Discreet flint and flame, Avid Film Composer 7.2, NewTek LightWave 5.6. 


 

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 TV." 
 
 
(a)
(b)
(c)
(d)
(e)
Figure 2-Some stop-motion scenes require a virtual set. These puppets were shot on a greenscreen table. The ruler alongside the puppets was used as a gauge for the LightWave camera (b). A matte was pulled in Digital Fusion with the intent to keep some shadow material from the greenscreen pass (c). The LightWave set was shot with a camera move matching the footsteps of the puppets (d). During the render, the alpha channel was saved with only the foreground roof and phone pole matte info (e). This was used later to pull them off of the background and put them in front of the stop-motion characters in the final composite (a). 

 

Putting the show together

Bailey: "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 frame counts." 
 
 
Figure 3
Figure 3-This picture illustrates several effects that were composited in Digital Fusion. The city and smoke were generated in LightWave. The character was shot on set with a bluescreen at the window. The reflection pass was shot by the stop-motion animators on every other frame. The Thurgood character faced a mirror tilted to the left, just outside the window. A bluescreen was positioned behind the camera. This pass was comped in lightly with a garbage matte isolating the reflection.

 

Routine fixes 

Fixes 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." 
 
 
Figure 4
Figure 4
Figure 4
Figure 4
Figure 4
Figure 4-This furnace jet is a typical effects composite (a). Thurgood is atop the boiler (b) when its front door bursts open in a jet of sparks and gas. There's a source image from the stage. A particle effect was created in LightWave using Particle Storm, and the sparks layer was rendered (c). The same particles were applied to Steamer within LightWave to render the gas layer (d). Glow effects were applied in Fusion during the final composite to complete the shot (e).

 

Enhancing effects

About 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 3). 
 
 
A painted background is used here, where an animator sets up a go-cart scene with a camera operator .

 

More than fixes

Ancillary 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 ( www.five-d.com/monsters_Digital 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. 
 
 
Figure 5
Figure 5-In this scene, everything moved but the go-cart. 

 

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 to life. 
 

Images courtesy of Will Vinton Studios and Jim Lommasson.

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