How Animation Works

How does animation work? To me, this is a really big and open-ended question. The answer depends on just what you mean by "work"; I think there are at least three different ways to approach "how animation works". All of them are based on what our senses, brains and minds do to build up a representation of the world we are in, moment by moment. This picture is emerging from modern neurobiology and neuropsychology, as we look deeper into just how our senses process the world and our minds emerge from our body/brain.

The Illusion of Motion

Animation is, first of all, created in a movie medium. A movie is just a sequence of still images changed in rapid succession. When objects appear in different positions in successive images, our visual systems tell us that the objects are moving. Each still image is called a frame.

With film, you can actually see the pictures neatly in a row on a strip of transparent plastic. With electronic and digital movies, it’s less obvious – you can’t see the individual frames on the storage medium. But here are some frames I grabbed from a videotape; it’s easy to see the changes in the successive frames.

The GIF image format lets us stack up the frames and change them at different rates. Here’s the dog at 3 frames per second:

You can see the individual frames easily. (“Frames per second” gets abbreviated to “fps” – it’s easier to read and less work to type.)

The illusion of motion starts to happen around 6 fps and improves steadily as the frame rate increases. Here’s the dog at 6 fps:

There’s some illusion of motion starting to happen. At 10 fps, it’s better yet:

And at 16 fps the illusion of motion is quite convincing.

It’s no accident that 16 fps was the standard frame rate for the first thirty years of the movies. Studios didn’t want to spend too much money on film by running the camera too fast!

The Art Illusion

For me, the second reason that animation works is an illusion that I don’t remember anyone ever mentioning. It’s one of those things that feels completely ordinary – because our visual systems, the combination of eyes and brain, do it for us automatically. It’s “the art illusion” – our eyes and brains together turn a few smudges on a surface into objects, animals, or people. We’ve been doing it - creating art – for more than thirty thousand years.

Artists went on to invent many ways to put lines and colors on flat surfaces to represent the world around us. Just recently we invented photography, which gives us the illusion that colored blobs on a sheet of paper (or, right now, for you on a computer monitor) are a little window into a world containing people and objects.

My snapshots show that I take pictures that are just as ordinary as yours.

This ability to see images as real objects (or “real” objects in images) is born into us. Young children will try to put their feet into photographs of shoes – their visual systems turn the photograph into the object. We all have to learn that realistic images aren’t the objects that they represent. And we can still be “fooled” by skilled artists, even though we’ve learned to distinguish between an image and an object. Any image that looks real at first glance is called “trompe l’oeil” (“fool the eye”, though it’s really fooling the eye/brain).

Line drawings are still just as effective as they have ever been. A few simple lines can persuade us that we’re seeing a face – even when it’s my artwork.

The Illusion of Life

Animation combines the illusion of motion with the art illusion to create – many things, depending on what kind of animation you’re watching. Animation actually predates the movies; animation toys have been “scientific curiosities” since the early 1800s. The earliest animations were all drawn. It took photography more than 50 years to become the movies and be used to make animation.

The earliest animations had a lot in common with the animated GIF images on these pages. They were short, simple, and played over and over again in a loop. A bit like this animation of my face drawing.

By choosing what to move in the face and when to move things, I create at least a bit of the illusion of life in the drawing. Of course, it helps that our visual systems are very finely tuned to recognize faces and facial expressions, and then tell us how the person is feeling. The drawing isn't a real face - but "wrong motion" in the eyes can still make us very uneasy.

We interpret body position the same way we interpret faces, and receive strong emotional messages from the way people and animals move. Estimates of how much we communicate through our faces and bodies range from 65% to 85%. Making art and objects reach an audience emotionally through motion makes animation an art - and a lifetime pursuit.