Prop Interaction with Dynamic Constraints

Interacting with your environment is an important aspect of... existing. I love touching objects, holding objects, picking them up and putting them down again, rearranging the world around me, and generally having a solid corporeal body. I’d wager you like doing those things as well, and your characters want to do them too!

Animating this can range from being blindingly obvious to devilishly difficult. If we want Rain to, say, wear a hat, we can parent it to a bone in her head and continue as normal; if she is to sit in a chair, we can just animate her sitting down and not let her pass through that chair; and if Rain were to kick a ball, we could animate it flying into the air at just the right moment.

So far, so good – but what if she were to pick up a ball in her hand and toss it? That requires making a dynamic constraint – an animated constraint that starts working when Rain touches the ball and ends when it leaves...