Sure, Meander can predictively draw the motions of characters to speed up the animation process. But that process wasn’t originally about style—it was an attempt to get paper animators to switch to digital by giving them a tool that could accurately capture a handmade curve through a drawing tablet.
Once the lines could be captured correctly, they could be made dynamic. The computer nudges the hand-drawn lines of a frame into the right positions for the next frame in a process called Final Line Advection. If you can imagine all the curved lines in a rustling dress, you can suddenly see the whole animation problem as Disney’s engineers did.
Why did Disney spend three years building its own animation software?
Andy Hendrickson, CTO: We’re interested in taking the artist’s original intent with the stroke they lay down on paper and making sure we can faithfully get that into a computer. So we looked at all the drawing tools out there. All of them. All the commercial tools, all kind of under wraps R&D things for drawing—and we were left unsatisfied. A lot of the tools don’t faithfully record what the artist laid down. Almost all of our artists found themselves drawing and re-drawing to try to basically beat the computer into submission—beat the line into what they wanted it to be.
That isn’t fun?
Hendrickson: You can go back and zoom in and nudge the line where you wanted it to be, but that’s a lot of extra work, and it kind of kills the moment of artistry. You become a line wrangler. So what Meander does is it accurately and faithfully represents all the pen strokes as they were put down and as vectors—something we have not seen in any other package in the world. It means that when the animators lay down a line on the computer, this is the line they wanted. They don’t need to zoom down, push around, retouch, zoom down, move over, zoom up, et cetera.
Do the animators tolerate drawing digitally now?
Brian Whited, Senior Software Engineer: You’re dealing with artists who have been drawing and animating on paper for most of their lives. And they’re so used to doing that, they have so much freedom doing that, so much control over the line, that it’s really difficult to sell them on something that’s inherently less precise just because it’s a computer and the hardware itself is a limiting factor. You have to do something that makes it more compelling than just re-creating what they’re used to, because it’s never going to be as good as drawing on paper in the near future.
What’s so good about drawing by hand?
Whited: The strength of a traditional animation is that you have an artist basically touching every single frame of the film. They can frame everything exactly the way they want at every moment in time. For CG films, it’s a little different. Some of the strengths they have on that end are that things can be very smooth, you can do very subtle motion, very slow camera moves that are very difficult to do in traditional animation because you have an artist drawing every single frame and any inaccuracies, any wobble in the line, is going to distract you. So they have these two sets of strengths that are very set apart and I think what we really wanted to do is try to take these two strengths and marry them together in a way that wasn’t distracting. You could have that hand of the artist right on the frame, while still having that very subtle motion or subtle expression or movement.
What was the development process like for Meander?
Whited: So using the expertise I had in both geometry and using modern hardware, I was just trying to come up with ideas, and I would iterate back and forth with artists. I would make a little demo, and I would go to an artist and ask them to draw curves, over and over again and say, ‘Does that feel right?" and they’d say "Oh, that’s a little off, that’s not exactly what I wanted." That was probably the first six months of development.
What’s different about the way Meander draws curves, after all that testing?
Hendrickson: To speak to the "secret sauce" part of Meander: There are two broad ways to represent a line in a computer. One is as a vector, and the other is as a bitmap. Bitmaps don’t scale well—if you scale them up and down, they get jaggy. Whereas, if a line is a vector, you can scale it up and it stays smooth. Most professional software that does a representation of a line that you draw uses the vector-based method, so that you can re-scale and resize and move it around. The trouble is, when you’re actually sketching on the computer, say, in an input tablet, the computer is trying to figure out which vector best fits the line you’re drawing and it turns out that they’re not very accurate. You can draw a line, and when you lift your pen it tries to fit a vector. It places the vector, but it’s not exactly the line you drew—it’s subtly off. And those small, subtle variations really change the nature of the expressions and the acting of the characters. It wasn’t working for us. Meander allows an unimpeded flow from the eye of imagination, to the hand on the computer, to the image you see. It’s much more of an unbroken continuum. In Disney animation, we practice kind of a dual art and technology development process where there’s an artistic challenge, and we go make some technology or bring some technology that we’ve previously made into the equation, test it out, move back, see what that does to the art, and back and forth. That’s how the development of the Paperman method came about.