Principles of Animation for Motionographers – Part 2 of 3

Posted October 14th, 2009 / By Jamie Peterson in Resources, Tutorials

This is the second post in a 3-part series where we’ll look at the Principles of Animation, developed in the early years of Walt Disney animation as they were pioneering the young animation field. In Part 1, we looked at squash and stretch, anticipation, and staging; and in this post we will be looking at animation processes and techniques that can be applied to your motion design work.

STRAIGHT AHEAD ACTION and POSE TO POSE

Straight ahead action and pose to pose are two approaches to animating in 2D animation. With straight ahead action, the animator starts at the beginning of a scene knowing what actions must take place, then draws each frame sequentially. This approach allows the animator to improvise as he goes along and will usually give your animation a bit of spontaneity.

In this scene from the animated film The Iron Giant, a straight ahead action technique was used most to animate the jittery child (~31 second mark), and allows more of a free-flowing stream of consciousness feel to the shot.

Pose to pose animation is the most common approach used with modern animation using After Effects and 3D suites. With this technique, you set keyframes to create keyposes at determined times. Unlike 2D cel animators, you do not have to draw inbetweens (also known as tweening) between keyposes as After Effects will create these for you. While it may reduce your workload, it can also produce unexpected results. In my workflow, I like to review both shot and keyframe in the storyboarded key poses that I know I have to hit. I then go through and give it a second pass of keyframes, still trying to keep my timelines as clean as possible. Finally, I repeat the application of more passes of keyframes as needed. This process of animating in passes ensures that you maintain proper timing and helps eliminate unnecessary keyframes that can make revisions a giant headache.

If given more complex objects like human character models to animate, I often try to break down passes into parts. Looking back to the robot jumping example in Part 1, I would first do a pass of animating just the position. When previewing a stiff character, you can still get a good idea if the animation is too fast or slow. Then, I like to move to animating the driving force; in this case the legs and torso, which allows the character to get from point A to B. Next, I would do a pass of animating the arms and head which help to flesh out the character’s anticipation, squash and stretch, and follow through (see next section). Now with a full rough animation, I will go through and add more passes to smooth out the inbetweens.

FOLLOW THROUGH

Anticipation, action, and follow through are the three stages of an animation. An action that comes to an abrupt end without follow through often feels unnatural, as if the object has lost all sense of mass, volume and velocity.

Just like you would account for in the anticipation and action stages, you have to think of the objects in terms of the same properties of volume, mass, velocity and weight distribution when animating follow through.

We’ll look at this animation from a recent project I had worked on as an example of follow through. As Kobe hangs on the rim after he dunks, his body and legs rocks back and forth from the momentum of his jump. Even without using the cutout model that the treatment called for, you can still get a sense of reality due to the movement on the swinging animation.

There are a few expressions that you can use in After Effects that will help automate some of these animations, but I believe that at times they can lack a natural feel to them no matter how mathematically correct they are.

SLOW IN and SLOW OUT

Slow in and out or ease in and out as it is most often referred to in motion graphics is used to distribute the inbetween frames between keyframes. The effect of this technique is most easily represented in a spline keyframe graph.

You can see that the ease ins and outs on the magenta circle gives the action a much less mechanical feel and allows you to have more natural feeling stop when actions like follow through are not available.

ARCS

When using the pose to pose process of animation, you will often get animation that is very robotic feeling where objects will move from point to point and lack a natural arcing motion. These actions lacking arc often feel as if they lack a sense of weight.

Arcs can be added to your animation by turning on bezier handles to your keyframes. You can create much smoother animations without having to add more keyframes to your timelines.

Using bezier handles in After Effects to create a circular motion path

Conclusion

All of these concepts are designed to help you better communicate your visual ideas, whether you’re an animator or designer. The tools are easy enough to learn, but the goal is understanding how to use them to deliver a message that is clear, convincing and hopefully interesting enough to take your work to the next level.

The finale, or Part 3 of this series to be published next Wednesday will cover secondary action, timing, exaggeration, and appeal. If you have any questions, feel free to leave a comment below.

REFERENCES:

Thomas, Frank and Johnston, Ollie, Disney Animation: The Illusion of Life, Abbeville Press, New York, 1981

Jamie Peterson is a freelance graphic and motion designer running the Portland, Oregon based MelonFresh. Aside from design, Jamie’s interests include reading, , writing short fiction (Pokemon fan-fic), cooking, listening to podcasts, sketching, dreaming up bad get-rich-quick schemes, and writing bios in the third person. He also thinks that this is .