I use a graphics tablet to draw directly in Flash, using the Pencil Tool set to smooth my lines as I draw them. You may wonder why my ball isn't exactly circular; in fact, it's a rather stretched ovoid, and that's one of the principles of animation that you want to keep in mind. A normal ball, when it bounces, shifts shape if it has any pliancy to it at all, as forces act upon it: gravity pulling, its own velocity creating pressure from the air, the ground pushing on it to deform it with impact.
Animation takes these minute shifts and exaggerates them so that they're larger than life. We covered this somewhat with the bouncing snowman in Lesson 14; it's called squash and stretch. I'm drawing my ball at the apex of its arc of ascent and descent, so it should be stretched the most at this point--though if I really wanted to be accurate, it would stretch on ascent, snap back to a squashed shape at apex, then stretch again on descent.
