Constraints with animated influence

Making Rain grab the ball was our first goal, and we achieved it. You did well! In fact, you did a little too well. Our next goal, ironically, is to make Rain not grab the ball, and I don’t just mean that for when she throws it.

Let’s go back to the beginning of our animation. This isn’t what we wanted:

Figure 10.20: The ball stuck to Rain’s hand at frame 1

Though the constraint works after Rain grabs the ball, it also works before she grabs it; the ball no longer rests on the table like it ought to. We need to be able to turn the constraint off somehow and wait until the right moment in time to turn it on.

It is for this reason that constraints have Influence properties, and they can be animated just like anything else.

Keying the influence of a constraint

The Influence property of a constraint is pretty self-explanatory. At a value of 1.0, the constraint is at “full strength...