Principles of Animation:

Believable Squash and Stretch

 

Introduction

 

                  To learn what squash and stretch is, pick up a piece of silly putty. Play with it a while. Now forgive me for pointing out the painfully obvious, but notice the following things: The putty never changes volume or mass. No matter how much you stretch it, fold it, bite it, sit on it, , etc., all that will change is the shape.

 

Drawing exercise: Imagine how silly putty could look when arranged into various interesting shapes. Draw the silly putty in various positions or forms. Imagine rolling it into a ball, stretch it out, squash it into a square, etc.  An interesting exercise would be trying to imagine how the putty could express an emotion---without using a face as a reference. It is necessary in this instance to conceive of the message to be conveyed;  for example, anger and arranging the putty into a lightning bolt like shape

 

                  All living flesh behaves like silly putty (to a certain degree). In motion, it constantly changes shape and size, but not volume. Try this: Flex your arm. (If nothing happens, try lifting weights :). Then bend it, watching the muscle that bulged when you flexed. See any change? As your arm is bent, the muscle bulges again. As you extend (stretch) your arm, the muscle thins and stretches. Every part of your body behaves that way. Just observe the simple mechanics of your hand as you squeeze and stretch your fingers.For that matter, it can be stated that i) anything not made out of plastic, metal, wood or stone will squash and stretch to some degree or another.

                  Imagine how a face can be distorted by certain emotions.  Observe these changes by looking into a partnerŐs face and making careful observations (the key to successful animation after all is based on minute observation skills); what happens to the nose, eyes,  mouth during  mood expressions?  Does the overall face shape change as a result?

 

Drawing exercise:  Create a face for a character and manipulate the movement of the features to suggest a gradual change from one expression to another.  Try to indicate the changes to the face as a pliable material (much like silly putty).  Draw these expression changes through 5  essential stages employing both squash and stretch.  Emphasize the form changes as the face changes in basic shape and structure;  eg ., perhaps a face that is happy then becomes sad, drooping and rubbery in appearance.

 

Writing  exercise:  Write about your observations throughout both drawing exercises and explain your conclusions  which support the notion that pliable forms can be used for specific effects in animation. List a specific effect. Why is observation important to the animation process?  How can Squash and Stretch help achieve this goal of motion or movement in an animation?

 

 

 

A Bit of History-Animation Principles

 

 

                  This seemingly simple fact was completely unknown in the early days of animation. As many animation students know, the early Mickey Mouse's figure was traced from two coins. This flat, rigid shape could never be turned, moved or distorted; it was always a two dimensional shape on the screen.

                  To see for yourself what sort of action this approach resulted in, consider a very simple movement, a bouncing ball. In those days, this would have been represented simply by a circle, moving up and down.

Further elaboration on the first stated fact would be: ii) Anything composed of living flesh, no matter how bony, will show considerable movement within its shape in progressing through an action.

                  But now it's time to get with the thirties. The Disney animators discovered that bouncing balls are not made out of rocks for a reason. When a rock hits the ground, it does not change shape (unless it breaks). It is rigid, and its downward momentum is completely spent once it hits the ground. When a rubber ball hit the ground, its downward momentum distorts (squashes) the shape of the ball. When the ball tries to regain its original shape, it pushes against the ground hard enough to throw it into the air.  The direction and force stretch the ball as it leaves the ground as gravity is still trying to exert a force against the bottom of the ball.  The result:  one  bounce.

 

Hit Me

 

                  The best way to draw the ball is to draw it as a circle at the top of the bounce, as a vertically elongated ellipse as it drops, and as a flattened ellipse for the one frame that it hits the ground (as illustrated above). The same holds true for a person; on the way down to the ground, the arms fly up, the legs stretch out, the neck extends. As the person hits the ground, the arms swing out, the knees bend, the head is jammed towards the shoulders. Quite simply put, as the person falls, his body is stretched and on contact with the ground, it is squashed. Does this process only apply to falling objects? Actually any part of the body will squash and stretch regardless  whether it is falling or not.

                  Try to imagine a scene from a cartoon you have viewed recently.  For example, there is the scene in Aladdin when Jafar surprises the Sultan while he's playing with his toys. The Sultan is startled and looks around quickly. The changes in the head are interesting to observe.   From its normal shape, it flattens out during the initial shock, then stretches out and twists as he looks behind him to see who's just coming barging into his room. What this picture should show you is that, although the stills look forced, unnatural and strange, it is in fact the most natural way for anything to move. Anything you animate without squash and stretch will immediately look rigid, uninteresting and definitely not alive.

 

Writing Assignment:  Discuss scenes from animations you have viewed in terms of stretch and squash.  Why were the particualar scenes memorable?  What was the emphasis for the pliability of the character, or  material-eg falling, etc. Which type of animation would best suit squash and stretch, the stop motion claymation or the standard draw and paint cartoon.  Explain your answer.

 

Drawing Assignment:  Using the scene shown to the left, try to develop both the next five frames and the  final five frames as you perceive the action to be for this shot. Emphasize a flowing movement.

 

 

Inbetweening

 

Frame Rates

 

                  Most people involved with the medium probably know that feature animation runs at 24 frames per second. Television can run as slow as 8 and as fast as 30. For quality animation, that means up to 30 individual drawings each second. It was long ago realised that the top animators at a studio should not be burdened with this amount of work. Animators are supposed to be actors with pencils; in other words they should spend their time acting and not drawing the same thing over and over, maybe changing the position of an eyebrow or finger. In the scene involving Aladdin (to the right) Glen Keane drew only a few frames (probably about 10) out of at least a hundred-frame long scene.

 

 

                  So another type of artist must take care of this work. That artist is called the inbetweener. It is his or her job to draw the frames which the lead animator leaves out. The vast majority of animators start their careers this way, and yet if you are animating at a smaller production house or at home, obviously there is not an army of inbetweeners waiting to clean up after you; you will have to do it yourself. It is easily the most boring part of animation, yet it is essential. And chances are, when you get your first animation job, it will be as an inbetweener.

                  Remember that a bouncing ball demonstrates both  "squash and stretch" in its movement within an animation? Most would only  bother to draw no more than an 8 frame animation. At 24frames per second, that ball will bounce three times a second - a bit too fast. But simply dd one inbetween for each drawing, doubling the number of drawings to 16, or one foot of film and the motion seems more within the bounds of reason.. This type of inbetweening is highly uncommon, for reasons which will later be explained, but it is simple and relatively easy to do. This being said, remember not to simply place the ball halfway inbetween its two key positions. Rather, remember that it is constantly changing speed and reflect this fact in your inbetweens.

 

Getting Started

 

                  Anyway, some basic terminology. The frames which the lead animator draws in rough are called the keys. (They are also called extremes; all extremes are keys but not vice versa). Usually these keys need to be cleaned up, to erase the sketchy look and change it to a smooth line. These drawings are called, not surprisingly, cleanups.  In a studio setting, the cleanup of keys will be achieved by the Key Assistants. It is then the job of the Assistant Animators, the Breakdown Artists and the Inbetweener to draw the remaining drawings (these artists are listed in descending order of importance). Using the keys, they will insert the required number of drawings in cleaned-up form. The number and nature of these inbetweens are determined by timing charts and, less frequently, exposure sheets. A timing chart is that thing besides Aladdin at the top of this page; it's to his upper right. You can see the "56" there - therefore this is the 56th frame of this scene. Underneath the 56 is a long vertical line, with a bunch of slashes across it. The long line is the "time line", and each slash is a frame to be drawn by a cleanup artist. In this case, you can see that the artist has left out 6 frames. Notice also that the frames are not evenly spaced out - they get closer together towards the end. This means that there will be a big difference in position from frame 56 to 57; a slightly smaller between 57 and 58, even smaller between 58 and 59, and so on.

                  The character shown before  has stretched out as a result of taking in extreme amounts of air.  The subsequent exhaling effects demonstrate the squash and stretch effects quite clearly.  The amount of inbetweening for a particular scene like this will involve the exaggeration and/or distortion of the actual character  as the action unfolds.

 

 

Drawing Assignment:   CO 10

Create an action and demonstrate the scenes inbetween that will emphasize the action involved. Try to use forms as opposed to linear drawings and focus on the distortion of the character/object involved.

 

Writing Assignment:  TO 10

Explain why the Lead Animator cannot be responsible for the Inbetween work for various scenes.  Discuss three reasons why this is the way the animation industry operates.  WHat are the advantages of first doing inbetween work before becoming a Lead Animator.