A simple ball doesn’t have much character. It is easy to make a boring old circle interesting. A good animator will apply timing to their drawing to create the illusion of fluid motion, while applying the principle of follow-through will make it more interesting by adding some flair.
Drawing a character bouncing up and down can seem like a very simple exercise to start animation, but it is actually not that simple. A simple bouncing character is a good way to start learning the basic principles of animation. This exercise allows you to focus on motion and ignore things like pose, composition, and personality.
If you were to animate a realistic bounce, the ball would follow an arc. Drawing sharp diagonals up and down may be tempting at first, but this is an opportunity to understand motion better.
Drawing each pose close together on top helps to show how the bouncing object actually slows down just before it comes back down. Drawing each frame further apart as the ball goes down helps convey the gravity of the situation. This principle is called spacing and is very important in animation. A ball would also rise quickly after touching down on the ground before slowing down to the next top. If you were to space each drawing out the same distance it would still appear to bounce up and down, but it would look very mechanical.
You might even be able to play with squash and stretch a little bit here. A realistic hard ball would not really squash and stretch, but a rubber ball would. So it is important to understand the difference. The character should only stretch when it is traveling at higher speed. When it hits the ground it will squash a little bit, but it shouldn’t take over. It should be there to support motion.
If you do decide to play with squash and stretch it is important to maintain the volume. Meaning, as the ball squashes down it should get wider in exchange. So it should still appear to be the same size even though it is being squashed down. As it rises and gets longer it should then get thinner in exchange, to give it the feeling that it is staying the same volume. If the ball were to get bigger while it is stretching it will draw attention to the size changes and take away from the overall concept of the piece.
Start out by blocking in the top, then draw the ball falling. Next, draw the ball touching the ground and finally draw the rise. Try not to worry about clean line work or adding any details. If you get the timing right, it will come together in the end. Reviewing the exercise with your drawings in real time is so much more useful than just going through each drawing individually.
Once you get the basic bouncing down you can duplicate the work and space the drawings out differently to compare how spacing affects motion. You may find that one set is easier to follow and appears to have more weight than the other.
Next, it’s time to get a little more creative. How will the energy of the bouncing ball dissipate? The ball will bounce a little bit lower each time it hits the ground. Your timing will have to change to compensate for this. Maybe the ball will eventually stay down on the ground for a couple frames? This will give the piece a slightly sticky feeling, which may or may not be desired.
This exercise really provides you with endless options to play with. You can change the timing and spacing, experiment with holding and adding in-betweens. It is a good opportunity to see how your animation decisions change a simple drawing into a fun character.