Motion

MOTION: a brief treatise of principles and concepts
by: Heidi Guedel
adapted and edited for CG 112

A BRIEF BACKGROUND
Our awareness of movement has been manifested throughout the ages. An Egyptian wall mural of 2000BC depicts the progressive movements of two wrestlers. Stages of a human’s running were depicted on ancient Greek vases, and the early Japanese created scrolls which could be unrolled to reveal a sequence of movements. Early American animation devices were created, by which a series of drawings were placed on the inside surface of a large tube. When the tube was rotated, a viewer could look inside the tube through a narrow outside slot, and the drawings would appear to move, as they rotated past the viewer's field of vision. However, it was the invention of the motion picture that finally provided a practical means of making a series of drawings appear to move.

In 1906, animation pioneer J. Stuart Blackton created the short film, Humorous Phases of' Funny Faces, in which faces drawn on a blackboard changed expression. Next, the short film, Phantasmagoria by the French artist Emile Cohl, was produced in 1908. It contained 2000 drawings. That same year, Windsor McCay created a film using his cartoon clown character, Little Nemo. After the success of that first effort, McCay created his now-famous, Gertie the Dinosaur, and traveled the vaudeville circuit. He designed a series of' interactive scenes, in which Gertie seemed to respond to McCay's questions, and to obey his orders as he stood beside a rear-projection, movie screen.

An early animation studio was set up in New York. At first, both the characters and background were laboriously redrawn for every frame. Thousands of frames of film were incorporated in the early animated shorts. Two intelligent men, J. R. Bray and Earl Hurd, invented the process of redrawing the characters on sheets of transparent celluloid. Then the characters were painted, and laid over a single background in succession.

In 1923, a man named Walt Disney came to California from Kansas City to organize the first animation studio in Hollywood. By 1928, he had produced the first, full-color, sound cartoon, The Band Concert, starring Mickey Mouse. Other studios followed Disney's lead, and during the next thirty years, the art developed to a level of excellence which produced such beautiful works of art as Snow White, Pinocchio, Fantasia and Sleeping Beauty. Although many other animation studios have been in business from the 1930’s through to the 1990’s, the Disney Studio pioneered the best methods of studying live motion, and translating it into entertaining, sophisticated, moving caricatures.

When Don Bluth Productions was founded in 1979, it was made up of 16 renegade animators from Disney Studios, of which the author was one. Bluth and his staff have done their best ever since to carry on and expand the tradition of excellence established by their "Alma Mater".

ANIMATION TECHNIQUE

The following discussion incorporates techniques the author absorbed while working at both Disney and Don Bluth Studios, as well as those developed over the last few years, in order to make use of the personal computer for animation production.

CARICATURE INFORM AND MOTION

The same considerations and interpretive instincts go into creating animated motion, as go into creating a caricature. You have to visualize what is especially characteristic of an individual and its motion, and exaggerate it; make it "larger than life." This exaggeration can create something funnier than the real thing, or more exciting, or more frightening, or sadder, or sweeter. What makes animation and caricature more entertaining than "real" counterparts, (such as photos and live-action movies), is that special element of artistic exaggeration. This pushes the audience response so much further.

Beginning with the action of walking; there are many ways to exaggerate and make a caricature of the walk. Are you trying to depict someone in a hurry'? Someone sad'? Someone chipper and frisky? Someone heavy. walking ponderously? Someone light, barely pushing off the ground? Some combination of the above? Begin with your starting pose. This first drawing should incorporate whatever your imagination can envision about what your character looks like, and the way it is walking. It doesn't need to be the first drawing in your sequence of motion. Perhaps the middle drawing will be the first one you create, in order to stimulate you to complete the action. Your starting pose, then, should be the point from which you can work backward and/or forward. Does this drawing evoke the feelings you intended when you created it? If it doesn't stimulate you, it won t stimulate anyone else. Follow a cardinal rule for success: please yourself first!

If your walking character is heavy, more drawings will be needed at the point where the ground absorbs the character's weight. During, the step, just after either foot makes contact, a really heavy character needs 3 or 4 drawings at 10 to 12 frames per second to allow weight to settle before it lifts up another foot for the next step. Next, at the height of the step, when the character is pushing off on the foot that’s still on the ground, and reaching forward in the air with the other foot, there should be about half as many drawings as are used to depict absorbing weight.

Normal Walk

Heavy Walk: Addition of 2 more inbetweens between 3/5 and 5/7 to slow movement of larger character.

If your character is lightweight, less time will be required to absorb weight and overcome inertia before taking the next step. The character might lift up a little higher, and remain in the air longer before contacting the ground again. Someone sad will walk slowly, slouch, and take heavier steps for their weight than a lighthearted, happy-go-lucky character, who might seem to skipover the ground. Your interpretation of the combination of physical and emotional characteristics of your character will determine how your animated walk will look. Study different people as they walk past you during, the day, and draw poses depicting their manner and stride.

If you've ever seen Disney’s animated feature. Pinocchio, you may recall the character, Stromboli; heavy set, bombastic, and very creative. The animator used this character’s weight and heavy build to create some very entertaining action. Whenever Stromboli would leap into the air, or take a step, his belly would lag behind a few frames, and catch up with him just as his body would be headed back down to the ground. Then the big belly would settle as Stromboli came to a stop. Disney animators coined the terms, "overlap" and "follow-through" to describe this process. Another good example from real life is the shampoo commercials on TV showing slow-motion footage of a model shaking her head from side to side. Her long hair trails behind, catches up as she turns her head back, and flies in her face as the ends continue on in the original direction: Thus showing "overlap" and "follow-through". Use of this technique creates animation that is fluid, and interesting to watch. Limited, "Saturday morning" animation almost never incorporates this technique, and therefore, the movement appears stiff.

Overlap / Follow through: Note antenna movement overlaps when head is suddenly jerked back followed by follow through action.

The other most important principle in full animation, is "squash and stretch". An organic form never remains rigid during movement. Early Disney animators studied live-action films of animals and people in motion. When successive frames were compared in slow motion, they were surprised at the amount of shape change that actually occurred. Bodies elongate and compress often in the course of normal activities. But, it is important to note that the total volume of the shape remains constant. An animator must envision the same amount of volume taking different forms. The simplest example is the bouncing ball. As the ball falls, it actually becomes, slightly oval, elongating from the gravitational pull, until it hits the ground. When the ball’s mass, traveling rapidly, encounters the ground, it flattens out. As it recovers from the impact, and its elastic properties return, it quickly resumes its spherical shape. It bounces back off the ground, and remains round until it passes the apex of the next bounce at the top of the arc. As the ball loses upward momentum, it feels the pull of gravity again, and it gradually elongates into an oval again, before hitting the ground.

Squash and Stretch

Animators commonly exaggerate "squash and stretch" for humorous effect. Recalling Stromboli, remember the way his body elongated and compressed as he stomped and leaped around. This, plus the overlap and follow-through of his body fat and clothing, resulted in a very entertaining series of animated scenes.

USING ARCS IN MOTION

When planning a path of action, remember that all natural motion takes place in an arc rather than a straight line. Most paths of action incorporate a series of arcs. If you think about it, you'll realize that only mechanical motion occurs in a straight line (for example, a train traveling down a straight track, or a pinball straight out of the chute). Consider your own body. Swing your arm. It follows an arc, because it is attached to your body at one end (the pivot point). All of our joints work this way, and so do those of other animals. When creating a body in motion, all of the arcs have to be graded smoothly, or the action will bobble. After you have created the extremes, the in-betweens must he done with the moving parts following the natural arc. If the in-between images are placed horizontally between the two extremes, the arc will be flattened out:

 

Body Arcs (Correct): Notice the 'bounce' and arcs of arms and legs (knees).

Body Arcs (incorrect): Showing body following linear motion path.

The movements of each part of the body will have their own arc. You should keep track of the head, shoulders, elbows, hips, knees, ankles and the wrists, and plot arcs for each of these parts of the body to develop an acceptable path of action. Another truth to consider is that if you accidentally flatten out an arc, notice that the arm, or leg on that in-between actually looks shorter than those on the two extremes, arcs have to simulate perspective, as well.

When drawing a turning head, beginners often do not consider the arc that the nose has to make during the turn. When the head turns from face-front to profile, the nose has to appear closer to the profile position halfway through the turn or the face will seem to flatten out.

If this is difficult to picture in your mind, try this example. Sketch a circle on a large piece of paper, and then divide the circle in half (through the center point, to each side). Then draw a straight line from the center of the circle, to divide the half circle in half. Then draw another straight line exactly dividing your quarter circle in half. Now take three pencils the same length, and put one on one side of the line dividing the circle in half, another on the line dividing the circle in quarters and another on the line between those two. Finally, bend down so that the pencils are eye-level, and look straight at the pencil on the quarter line (that should be pointing right toward you). Do you see that the end of the pencil in the middle (the in-between) looks like it is closer to the end of the side pencil, than the end of' the pencil pointing right at you'? Your animated arcs need to be in this perspective, too. This is one of the most challenging concepts to perfect.

Head Arc

PLANNING YOUR TIMING

"Extremes" describes the drawings done by the animator to plan and describe the path of action taken in an animation sequence. The drawings done between these extremes are known as "in-betweens". The animation "in-betweener" receives a set of extremes with instructions concerning the in-betweens to be created. At most, traditional animation studios, a standard system of notation, called a "timing chart", is used to indicate the number of in-between drawings necessary to complete an action. For example, a set of extremes have been created which are drawings ( I ), (5), and (9). A typical timing chart would look like this:

Note that the in-betweens from drawing (1) to drawing (5) are evenly spaced; indicating that drawing 3 should be done exactly in between (1) and (5), and that drawing 2 should be exactly between (1) and 3, and drawing 4 is exactly between 3 and (5). This is known as "even timing". Now notice that between extremes (5) and (9), the first in-between, number 6 is exactly in between (5) and (9), while in-between 7 is exactly between 6 and (9), and in-between 8 divides the space between 7 and (9). Because the spacing is re-divided as it gets closer to the last extreme, we call this timing, a "slow in". When the timing is re-divided out of the first extreme, we call it a "slow out";

The numbers of the extremes are always identified by parentheses.

The more drawings there are between extremes, the slower the action will move. So, more drawings near the first extreme slow the action out, and more drawings ahead of the last extreme slow the action in towards the end. Natural timing is not usually even. Too much even timing tends to make the action "mushy" and mechanical, as Don Bluth used to say. In fact, Mr. Bluth made a strong point in his animation lectures about a concept he referred to as "Texture". Texture is achieved when the timing is varied between crisp and mush action; restful and frantic action. He compared it to an interesting piece of music; a variation in tempo, volume, and orchestration.

There are different variations in timing charts. The above timing example consists of dividing and sub-dividing the space between drawings by one-half; another type of timing is known as "thirds":

The first in-between in the above example is particularly difficult to draw, because it is two/thirds closer to one of the extremes than the other. After the first in-between 2 is done properly, the second one 3 should be done exactly between 2 and (4).

When creating an animated scene, I learned to draw my basic poses first, and then break them down until I've created all of my extremes. Most of the time, it is helpful to create (shoot) a "pose test". This is when each of the extremes is exposed for the approximate amount of time needed to bridge the action between it and the next pose. An example would be if pose #1 is estimated to require 3 drawings between it and the next pose; i.e. if pose#1 is estimated to require 3 drawings between it and pose #2 (drawing #5 in that eventual order), then pose #1 is repeated four times, and so on through the rest of the poses. This will create comparatively stiff transitions, but the scene will play at the proper timing and use up the total number of frames. You can then determine if the estimated timing between poses creates the effect you envisioned. Changes can be made before the effort of drawing all the in-betweens, some of which might no longer be needed after changing the timing!

ANTICIPATION

Most characters’ actions will be preceded by a distinct "anticipation". If you've ever seen the Road Runner lean backward before he takes off at a run, and then disappear in a puff of smoke, that first action is the anticipation; it visually gives away the character’s next move, and prepares the audience to notice it. It is always opposite to the following motion.

A typical use for anticipation is just before a "double take", or look of surprise. The surprised look consists of wide-open eyes and mouth, eyebrows raised, face elongated, and neck stretched out. The proper anticipation is exactly the opposite: closed and squinted eyes, eyebrows scrunched down in a frown, mouth tightly shut, and head down between hunched shoulders. Notice that the element of squash and stretch is essential to creating contrast between the anticipation and the following action. The action always slows out of the anticipation in two or three frames, depending on your frame rate.

Anticipation

The nature of the anticipation should provide contrast, offsetting the resulting action. This contrast consists of timing (the speed of the anticipation differing sharply from the speed of the following action), shape change and change of expression. When the Road Runner anticipates his take-off, he halts in place for a moment, leaning back, arms raised, chin tucked into his chest and moves through a squash before leaping suddenly away in a stretched out run. A runner at the starting line kneels down like a coiled spring, then stretches out completely as he pushes off. A character about to explode in anger might ball up, squint, moan and growl a little and shake. Then he might open up and flail his arms, eyes bulging, mouth wide open and yelling with his body extended. Almost every action will benefit from a leading anticipation.