Eye Candy

Few things are more important to a dog than food, but a dog has little choice about which food lands in the bowl. It is a dog's conundrum, and meat for a charming short animated film written and directed by Pixar's Patrick Osborne.

Osborne cooked up the idea of using food to drive a story after beta-testing a friend's "1 Second Everyday" app.

"I shot one second of every dinner I had every day," Osborne says. "The video of every meal was neat. So, I came up with the idea of telling some kind of story of a family using dinner cues to push the story along."

Osborne blended the "one dinner every day" idea into a coming-of-age story about Winston, a Boston terrier, and food choices made by the humans who feed him. Although no one calls the human characters by name in the film, Osborne named them after his grandparents. James is the single guy who adopts Winston, and Kirby is the girl he meets.

Osborne, who had been head of animation on "Paperman," was working on Big Hero 6 when the opportunity to propose a short film arose. He developed his story at night, after work.

The success of Disney Animation's shorts "Paperman" and "Get a Horse" had led the studio to offer others the chance to pitch short-film ideas using a process much like that at Pixar.

"We pitch three ideas because John [Lasseter, chief creative officer at Walt Disney and Pixar Animation Studios] likes to see who you are in a broad sense," Osborne says. "But, he only talked about 'Feast.'" As soon as he said, 'Go,' the pitch became a promise. It was daunting to realize I would be making something that had to live up to 'Paperman' and 'Get a Horse,' and the whole history of Disney shorts. But, the studio gave me lots of support."

That support would be needed because Osborne envisioned a short film with a unique, untested look. Jim Reardon became Osborne's story mentor; Jeff Turley, the production designer; and Josh Staub, the visual effects supervisor.

Osborne had studied painting and animation at Ringling College of Art and Design, and he still paints - life drawing, figure painting. He brought paintings he and his friends had created to the pitch.

"I wanted to bring those choices and sensibility into 3D," Osborne says.

With that in mind, Osborne made a commitment to the production designer.

"My promise to Jeff [Turley] was, 'We will make your paintings move,' " he says.

Simple But Not Easy

"Some people put brushstrokes in an image to make it look like a painting," Osborne explains. "But brushstrokes are the result of paper texture and paint, and that doesn't make sense in 3D animation. Where does paper texture live in depth and motion? It's better to think about what makes a good painting."

Thus, rather than adding brushstrokes, they looked at the reasons why a painter makes particular decisions.

"Jeff drew the focus by making edges fall away," Osborne says. "That gives you the feeling of a painting. Also, we looked at color values. Josh [Staub], Jeff, and I did rough value composition sketches for each new shot in the film. We pinned all those up on the wall with the storyboards and Jeff's paintings."

The technical challenge in making the film look like that artwork fell to Staub and his crew.

Light hits clearly defined planes with no fall-off, and thus maintains Winston’s graphic design.

"It isn't what we normally do," Staub says. "Often, we get visual development work that's more for inspiration. For 'Feast,' one of the fun things was making the film look as much like the visual development as possible, but in motion. When I looked at the artwork, it was clear there wasn't a lot of shading and the flat, loose edges would be a challenging, interesting component."

Staub asked Turley to provide one piece of artwork that could be in the movie and, in that one frame, would have all the challenges they thought they would face in that one frame.

Turley provided an image with Winston in the center and lit from behind.

"It also had food," Staub says, "a piece of pizza with cheese stretching. It had steam, so it gave us a chance to think about what those effects would look like. He had used color to block in things in a simplified way that allowed you to get a quick read. It had shallow depth of field. And, it had loose edges."

Trying to get such a simple and appealing look is the hardest thing to do, notes Staub.

"I think that's true with any kind of artwork. You want to draw the eye of the viewer, and you do that with the same techniques, whether you're doing a painting or working in a computer," Staub says. "What we wanted was a quick read on things. The story has one-off shots, with images on screen only for a second. We had to focus the viewer's eye quickly through value, color, shape, and depth of field."

With the painting of Winston and the slice of pizza at hand, the crew sought to match Turley's artwork in 3D.

"We had a goal defined by this one image," Staub says. "We worked with all the departments - modeling, rigging, animation, layout, look, and lighting. Everyone had to think differently. And, slowly and surely, we got closer and closer until we felt like we got there."

Modeling

In most CG films, the models are complex, with shading that creates a realistic look when lit. Not so in this film.

"We have a chair with buttons on the cushions," Staub says. "When a modeler first built it, it looked rounded and smooth and detailed. It could have been in any of our movies. But for this short, we had them model it almost like a box, so that when the light hit it, it would hit clearly defined planes. Usually when the light rolls off the edge of a surface, you'll see a gradation, light that softly turns into dark. We didn't want that in our show. Things would be lit or in shadow."

For example, if Winston were in another film, the light would softly fall off the side of his head to show a rounded shape. In this film, when a light is above Winston, only the top of his head and the bridge of his nose are lit.

"We tried to build everything - from the chair, to the TV, to the characters - as simply as possible so the light shapes that resulted would be simple and clean," Staub says.

Rigging and Animation

Rather than focusing on what happened inside a model, the rigging and technical animation team concentrated on the silhouettes.

"The posed shapes had to be simple, clean-lined, and designed," Staub says. "The animators looked carefully at shapes and silhouettes. Even when Winston is sitting or standing, his silhouette is graphic and very defined, without many bumps. There is no extra detail around the silhouette. We didn't want wrinkles in characters' clothing; we wanted it to be graphic. It's hard to do this, to make a rig that allows for clean, nice, elegant silhouettes. We had to give animators controls to simplify the edge of a shape. It was so important to not have complex silhouettes."

Animators could turn on a view with flat lighting that looked very close to the final rendering. 

"It was important for the animators to work in the context of the film as much as possible," Osborne says. "We approved shots out of technical animation with only flat, surface shading."

When the rig couldn't define a shape in a smooth, elegant way, or the flat lighting made a shape hard to see, the technical animators could turn to SilSketch, a proprietary plug-in for Autodesk's Maya.

"You can draw a line on a Wacom Cintiq, and SilSketch makes a 3D blendshape," Osborne says. "It makes a model shape that matches the line and turns that shape on. You can blend in and out. We use it on every movie for very graphic statements."

Also, to accent folds in skin and clothing that would otherwise be flat because of the lighting, the artists used a proprietary tool called Meander. With Meander, which Disney's R&D team developed for "Paper­man," artists draw on the CG images and the software accurately converts the hand-drawn lines into motion vectors.

Effects

Of the 80 shots in the animated short film, 60 had effects created by a team of 10 artists.

"When you have food, you have effects," Staub says. "But what you get from a simulation out of the box wasn't what we were after. We wanted every drop of ketchup, every piece of popcorn, to look natural but designed in the way it splats on the ground or pops out graphically. When James slaps a scoop of ice cream on the table, it had to have a shape we would paint, not one that would happen in the real world."

Thus, the artists sometimes used a simulation as a starting point, and then changed it. Rigid-body dynamics might pour kibble into a bowl, but the artists would remove any bits that didn't bounce and land in the graphic way they wanted.

When the cheese from the pizza slice stretched, Turley wanted it to break apart in clean, oval shapes.

"We had a lot of hand-animation in that shot," Staub says. "We had people on the simulation side and on the hand-drawn animation side working together on shots to achieve the final look."

The steam rising from the pizza, for example, was a hand-animated effect added during compositing.

"We wanted the steam to have a beautiful handmade swirl," Osborne says.

Layout

With attention focused on giving the audience a quick read with simple shapes, the sketches created by Osborne, Turley, and Staub showing color values and light shapes helped drive layout design.

"There was a rule that when Winston was in the light and the food was in the light, things were good for Winston," Staub says. "When they were in the dark, or when light was on the humans, things were not good for Winston. We could tell what story was being told because of these simple light shapes."

In fact, when they first showed the short in its early stages, they showed it in layout, rather than storyboard form.

For camera staging, the layout team focused on the center of the frame.

"We made sure the meals were right in the middle of every shot, right in the center, because in the dog's life, food is in the center," Osborne says, but adds, "until we see Kirby's parsley off to the side. Then, Winston decides to get [James and Kirby] back together."

To help draw attention to Winston and the food, the layout team designed shots with shallow depth of field.

"Anything behind or in front of Winston and the food was much less important," Staub says. "Sometimes we even put shapes out of focus close to the camera."

Because Osborne drew on the "one second a day" idea for the film, the film has fast cuts and one-off shots. Keeping the focus on Winston helps make it possible for the audience to easily follow the story.

"We never change where Winston is on the screen," Osborne says. "You don't have to look around to find him."

Look

Again, the word is, "simple."

"We had to unlearn what we normally do to achieve the look," Staub says. "We wanted almost flat color for everything. We didn't have much detail in the textures. We wanted everything flood-filled and simple. But once you strip out everything, when something is in complete shadow, you don't know what it is at all. So, we had to find a balance."

Sometimes that meant using color or value to define shapes. Staub gives the example of an empty, brown bookcase in a dark area. With no shading or shadows, it looked like a brown square, but by darkening the inside or sides, it took shape again.

"The whole idea of color and shape is the reason Winston is a black-and-white Boston terrier," Staub says. "It was a good way to read him in the environment without adding detail. We used his black-and-white pattern to define the contours of his body. If he puts a paw in front of a leg or his head turns, you can see his pose because of the black-and-white shapes, even in flat lighting."

Winston's black-and-white pattern didn't change, but his colors varied subtly as artists, working in [The Foundry's] Nuke, used value and color tints to help define his shape. "We might make his black fur not quite so black, or tint his white fur," Staub says. "Other­wise, when the white on his chin goes over his chest in flat lighting, if they are the same white, you can't define where his chin ends."

And if that weren't enough to distinguish the internal shapes or expressions, the artists would sometimes draw lines between them.

"When you render stuff flat, you need to add certain details to get expressions to read," Osborne says. "We drew the lips for the entire show because in the 3D version, they would thin out to camera. We'd want a consistent line."

They never, however, drew lines around an external shape.

Lighting

"Lighting was where we achieved the look of the visual development," Staub says. "We could get good clean shapes in the silhouette and in the animation and technical animation. We created the look with simple light shapes, edge breakup noise, and swinging color."

To create the light shapes, artists used a hybrid process with 3D lights and painted shapes. 

"Everyone on the lighting team  was also a painter," Staub says. "So, a lot of the work was done by painting light shapes in [Adobe's] Photoshop and projecting them into the background in Nuke. In fact, we asked for Jeff's lighting keys - the entire Photo­shop document, which might have 50 layers - and gave them to the artists to see his process."

Winston and his food are nearly always centered in the frame. Shallow depth of field also kept the focus on Winston.

The lighting artists might begin with simple light shapes created in the studio's 3D lighting system, called DLight, and use those shapes as a starting point. Often, though, they would replace them with the painted light shapes.

"No matter how simple we made the geometry, there was no way to avoid too much complexity when a 3D light hit it," Staub says. "The moment we introduced self-shadowing or complex geometry shadowing, it stopped looking like our movie. Sometimes the most appealing shape was a line of light cutting through a body."

To achieve that look, they created a "plane tool."

"Think of it as a 3D roto shape that we animated through a scene," Staub says. "It would follow a character, and that would be a rim light. When Winston was running through a scene and we wanted him to get hit with light, instead of putting a 3D light out of the box on him like we normally would, we took a plane in Nuke and sliced it through where he was running."

That put light on one part of his body and left the rest dark. Equally important, his legs and ears didn't cast shadows on his body.

"We let the environment cast shadows on him and let his body cast shadows, and that was enough," Staub says.

Breaking Edges, Swinging Color

The simple models, controlled silhouettes, flat shading, and light shapes created a look that matched the visual development and Turley's test image, but it wasn't enough. They needed to, as Osborne described it, make the edges fall away.

"We didn't want a painterly look," Staub says. "What we wanted was a breakup that looked like you ripped a piece of paper cleanly. We had it happen internally, not just the on edges, so we didn't have defined edges. All the pixels on the screen would get pushed and pulled based on a noise pattern and how much the artists wanted to push and pull the pixels."

The process happened in Nuke after rendering, which was accomplished using Disney's new, proprietary renderer Hyperion (see "Science Project," page 30).

"Normally, if you apply noise, like a filter, when a character animates, you get a screen blur effect as the character moves through the noise pattern," Staub says. "So instead, we created a procedural noise pattern on every animated object in the scene using separate render outputs. Within Nuke, we pushed pixels around using that noise pattern. Because it was baked onto Winston, for example, it would stick to him."

Because the noise pattern was specific to each object, the artists could use less noise for some, such as Winston's dog bowl, and more for a carpet or Winston's fur, and thereby change the material property.

The team also rendered out each object separately to control and change the color values.

"We would take the surface color and swing the value of every object in the scene in Nuke," Staub says. "The render output would have red, green, or blue for every object as a way to create mattes, so we could select elements and apply color changes. Winston's black might be blue, his white might be green, his tongue red, and in separate passes, his eye white might be green and his iris blue. His collar and tag would be two different colors. A cabinet's wood parts would be one color and the knobs a different color. That gave us access in Nuke so that we could swing the colors or darken and lighten the values."

Continuity and Challenge

The resulting Nuke scripts were heavy and complicated.

"We assembled a lot of pieces in Nuke," Staub says. "When I show people the scripts, they think it's extremely technical. But, every node in our Nuke graphs is an artistic decision to maybe make that couch a little lighter and Winston a little darker. You do that in Photoshop, but you don't have a crumb trail. Nuke gave us that crumb trail."

To maintain continuity in the way the film looked, the process the artists used was necessarily rigid.

When Winston isn’t in the light, his world isn’t good. A procedural noise pattern helped give the edges a painterly quality.

"We used the same technique for the edge breakup throughout, and added it in the same order," Staub says. "The artists all started with surface color. Made color adjustments. Added the light shapes, then the edge breakup and the depth of field. If they changed the order, it would look radically different."

However, because each shot was a one-off, and because time passed quickly, shot-to-shot continuity didn't matter. The couch could be darker in one shot than in the next. Artists had creative freedom.

The result is a delightful film with a look that truly brings concept art onto the screen in a 3D world. The look is unlike that of any other film.

Food might be the most important thing to a dog, but artists are fueled by creative challenge. 

"Artists don't want to always do the same thing," Staub says. "We want to stretch and push into uncomfortable areas. When we started the show, we didn't know how to do much of what we needed to do. So, it was very satisfying. It's such a great feeling when we achieve something that's new. We can take that knowledge to the next show."