Making the ball bounce

How should a ball bounce? Unlike the magical color-changing cube we animated in the previous chapter, a bouncing ball is something you’ve seen in real life. This makes it a bit more challenging – we already have an idea in our mind as to what a bouncing ball ought to look like, so there are right and wrong ways to achieve this effect.

For guidance, we’ll look to the laws of physics, which preside over the motion of things such as bouncing balls. Since we’re animators and not physicists, these laws are just guidelines we can take or leave – this particular ball, for instance, will eventually be made to bounce and roll forever. Nevertheless, knowing a little physics will help us anticipate the forces at play and determine the best interpolation modes for our F-curves.

According to Newton’s first law, an object in motion shall remain in motion unless acted upon by an external force. What this means is that force is...