F-curve extrapolation
Presently, the ball bounces exactly once, which is not very exciting. It also stands still before frame 10 and after frame 90, which is not a good look either. To fix this, we could simply duplicate the bouncing keyframes a few more times and shorten our scene frame range. There’s a better way, though – one that will keep our ball bouncing and rolling... forever. We can accomplish this quite easily using a feature called extrapolation.
To understand extrapolation, imagine that the F-curve has a finite “main” segment between its first and last keyframes. Now, try to look at the rest of it, where it ends. You’ll be zooming out for a long while. The F-curve is eternal; it has no beginning or end. It can’t disappear just because there are no keyframes left! It must always have a definite value, even before the animation begins, and long after it has ended. Extrapolation is our word for what an F-curve should do for the...
