I like the combination of miniatures and CG — It brings together the hand-crafted feel of practical elements with the flexibility of animating a CG character. Sure, it’s more work, but the result is worth it. Speaking of more work: The character rigs aren’t exactly action-figure-simple, but that’s true of any good cartoon rig. CG cartoon animation calls for carefully, patiently crafting every pose; not very far from drawn animation but far enough that it has its own place. While it borrows a lot from stop-mo and drawn animation, it adds its own unique touch and does what only it can do.

More on that later.

Toon Shader Basics

If you know the basics of a toon shader in Maya, feel free to skip ahead to Building Moom’s Shader.

A simple toon shader in Maya is a surface shader fed by a ramp containing two colors: The fill and the outline. This ramp isn’t driven by a regular texture placement node, but rather a SamplerInfo node.

Basic toon shader network (click to enlarge)
The SamplerInfo node has many useful properties, one of which is called facing ratio. This property indicates how directly a point on the object being rendered faces the camera. Here’s a definition from the Maya help files:

Facing Ratio gives you a number between 0 and 1 that tells you if the point being sampled is facing towards or away from the camera. A value of 1 means that it is facing the camera head-on. A value of 0 means that is is facing 90 degrees from the camera.

Facing Ratio explained

In a toon shader, the facing ratio of the SamplerInfo node is used to pick the color from the shading ramp. A point along the object’s edge is turned 90 degrees away from the camera, so its facing ratio = 0 and it gets the outline color. A point directly facing the camera has a facing ratio = 1, so it gets the fill color.

Basic toon shading ramp (click to enlarge)

Moom’s shader is built around this same basic structure, but adds a few bells and whistles along the way. Let’s take a look!

Building Moom’s Shader

In a nutshell, Moom’s shader is made from a soft, custom toon shader multiplied with a painted texture.

The complete shader network (click to enlarge)

Part A: The painted texture

The only reason I had to paint a texture here was to turn the inside of the mouth black, darken his lips and the soles of his feet. I felt it needed that contrast. Here’s the texture, superimposed on his UVs. Very basic, as you can see.

Painted body texture (click to enlarge)

Part B: The procedural shading network

The “soft toon shader” I mentioned earlier builds on the simple toon shader concept, but with a few interesting tricks. For one thing, instead of a hard toon line, I have a soft gradient on the shading ramp.

Final shading ramp

Since this part will be multiplied with the painted texture, most of this ramp is white. The multiply node in Maya works pretty much like the blending mode in Photoshop. Any color multiplied with white stays the same, so where this ramp is white, the final shader will look just like the painted texture. Where this ramp has color, the painted texture will get darkened and shaded by it.

Which brings us to the last part: How do I decide which color to pick from the shading ramp?

I’m doing this in two ways: With a SamplerInfo node, and with a little procedural NPR (Non Photo Realistic) network I built. Then I average the result of these two to get the final look (More on that in a bit).

We’ve already seen what the samplerinfo does; so I’ll just talk about what the procedural network is doing here.

The procedural shading network (click to enlarge)

It starts with a regular shiny Phong shader with a fractal bump map on it. The bump map’s job is to break up the shading and make it look rougher. It won’t really end up looking like a bump, as you’ll see.
The output of the Phong shader is clamped to a number between 0 and 1. Without getting technical about the clamp, I can say that I’m using it like “auto levels” in Photoshop: the lightest part of the shader is forced to become 1 (think of it as white), and the darkest part is forced to become 0 (black).
In effect, the clamp reduces the shading of my bumpy, shiny phong network to a simple number between 0 and 1. The samplerinfo node also provides me with the facing ratio which ranges from 0 to 1. The final trick here is to use the average of these two numbers to drive my shading ramp.

The Average Trick

While creating this shader, I first tried each of the two approaches by itself. The SamplerInfo node — which responds only to the facing angle — gave me a nice clean toon outline, but the result looked too flat and bland. On the other hand, the procedural network I made — which responds to the light in the scene — had some good rough texture, but its result looked too typically CG; too hard and plastic. By averaging both of these, I got the best of both worlds. See the images below.

And that’s how it works! If you have any questions or suggestions, please leave me a comment. If you try out this shader on your projects, please share the results! I’d love to see what you come up with.

Other posts in this series:
Behind the ‘toons, part 1: Backgrounds

Like that one, it’s got plenty of issues, but it was fun to animate as a quick study. It’s a heavy run, contrasting the prisoner’s extremely light one. His size and shape got me thinking he’s a mean cop, but somewhat dull and oafish. Something about his design suggested he’s the bad guy, and the prisoner’s the “good” guy! If these were for a real game, you’d play as the prisoner, running from this meanie as he tried to bludgeon you.

Yeah, I’m full of happy thoughts.

Here’s the 720X540 version. Enjoy!

Since his feet are tied to a chain, I imagined him running with short, extra fast steps, and his upper body lagging behind. The torso is a bit stiff, but I had to call it done. On to the next one!

Note: Want to see the high-res loop? download the 720X540 movie to your computer and enjoy!

Since the animation in both scenes follows the classic Looney Tunes mold (more on that in a future post), the backgrounds had to fit. I looked at frame grabs from those classics, some good old Hanna-Barbera ‘toons, as well as some “Cartoon Cartoon” shows like Dexter’s Lab and Jonny Bravo, since their BG style is heavily influenced by the classics.

On to the nuts and bolts! Both these scenes involved camera pans, so the BGs had to be much larger than 720X540. Here’s how I built them up. note: Click on any image to see the full-sized version.

The Stair Fall Scene

I started by taking screen caps of my viewport at different points in the animation, and lining them up in Photoshop so it looked continuous. The stairs really helped with the alignment.

Screen captures (click to enlarge)

This decided the final size of the painted background. No way was i going to start painting without knowing that! My screen captures were a bit bigger than 720X540, so I knew I’d end up with a bigger BG than I actually needed. Better to scale down a big BG than the other way around, right?

Here’s the base color layer. Ouch! hurts the eye, doesn’t it?

Base color (click to enlarge)

It’s painted in Artrage, a great free software that simulates natural art media. That’s how I got those nice brush strokes you can see in the enlarged image.

I then overlaid some high-res concrete wall textures, played with the blending modes, and adjusted the colors. Adjustment layers are my friend.

Textured and color-adjusted (click to enlarge)

Finally I painted some grid lines for the floor — just the part of the floor we’ll see in the finished scene — and overlaid a rough paper texture to break up the shading and make the colors slightly warmer.

Final background (click to enlarge)

Here’s the painted stair itself. Even though I had modeled a staircase in Maya (If you can call a flat plane with some faces deleted a “model”), I ended up using this painted one in the final After Effects comp.

Stair texture (click to enlarge)

In After Effects, I had two layers of stairs (one in the foreground for him to run up, and a blue one in the distant background) and one layer of the main background. I hand-animated them to match the animation, moving them at different speeds to create some illusion of parallax. Tedious, but it’s all I knew!

The Bee Chase Scene

For this scene, I wanted a very minimal background, to let the animation be the star. I chose a watercolor look for its subtlety. The wet media brushes included with Photoshop worked great for this effect.
Once again, I started with a series of screen caps. Here the alignment wasn’t as easy, because the perspective on the grid lines keeps changing from one screen cap to the next. I used his foot positions to help me guess the alignment. For the final pan in After Effects, I knew I wouldn’t have to worry about perspective. If a flat pan worked for those old classic ‘toons, it would work for my little scene.

Screen caps (click to enlarge)

Here’s the sky, made up of three layers — each painted with a different brush.

Sky layer (click to enlarge)

Then the ground and foliage. The foreground and background foliage are in different layers, so I could sandwich the animation between them in After Effects.

Ground and foliage added (click to enlarge)

Finally, a layer of random splatters and another with a paper texture overlay at reduced opacity. Here’s the final BG:

Final background (click to enlarge)

As with the stair fall scene, the BG pan was hand-animated in AE. Not much parallax in this scene, though.

It may sound from this post that I knew exactly what I was doing when I made these backgrounds. In reality, my process wasn’t a straight, simple sequence like I outlined above. There was a lot of trial and error (and plenty more error!). I had to go back and forth between the different “steps”, changing things on the fly. The breakdown above is just a simplified guide, and it’s all I can remember!

I’ll write some more posts about these scenes, going over the shader and other things. If you have any questions, or ideas about what you’d like me to elaborate on, please leave me a comment!

Another cartoon animation exercise. The focus of this one was to come up with a simple story and animate it to a musical beat. It started as an assignment during my last APT session with Keith Lango. Big thanks to him for the assignment, and for the insightful feedback!

I’m loving this animation “style” and the freedom it brings. Being able to work in a rough, loose manner without fretting over tiny details is really liberating. I’ve actually started to like the little imperfections and the roughness, as long as they fit with the energy of the moment.

As always, C+C welcome.

Painting the backgrounds was a lot of fun. They’re heavily influenced by the golden age cartoons, of course. And if you’ve seen the recent trio of cartoon paintings I posted(here, here and here), you’ll spot all three of them in the background of this piece. Yes, that was the plan from the beginning. Although making those paintings was great fun in itself.

Enjoy!

Directed by Kunio Kato. Winner of the 2009 Academy award for best animated short.