- Animation Principles in Practice: The Bouncing Ball
- Elastic Reality: Squash and Stretch
- Easing Transitional Action: Slow In and Slow Out
- Anticipation: Getting Ready to Move
- Additional Animation Principles
Easing Transitional Action: Slow In and Slow Out
The main movement of the ball is its up-and-down motion. Its secondary motion and animation are its squash when it hits the ground. Overlapping actions don't just begin and end with an abrupt jolt; there needs to be an easing or slowing in and out of the movements, which in max is called interpolation. Animation without Slow In and Slow Out between the keyframes appears abrupt, mechanical, and stiff. In the animation of the ball, you can see that its path of action, the bounce, already has some of this fluidity, but it's too rubbery at the top of its bounce and the interpolation needs to be adjusted to create a more real appearance.
Slow In and Slow Out also relates to the weight or mass of an object. An oil tanker takes longer to get up to full speed and longer to stop than a speedboat will. How quickly or slowly an object acts and reacts to an external force tells you visually a lot about the object. The way the ball moves in space and reacts to the ground when it squashes is what tells you that it's a ball, not a glass Christmas ornament.
In max animation, Be´zier Tangent controllers are used to create different types of keyframe interpolation. Click and hold on the In box, shown in Figure 15.
Figure 15 max uses six Be´zier tangent types to automatically control how an animation's in-betweens are interpolated between keyframes. This allows you to use precision control for the Ease In, Ease Out factor of your animation.
There are six tangent types; it is important to understand what they do because you will be using them to finish the bouncing ball exercise and the animation of the bug in this lesson's workshop. Here are the definitions of each type of Be´zier Tangent controller. You'll make adjustments to your ball bounce animation to include these tangent tools after the concept of anticipation is discussed. It's important to note that these icons when seen in the Out section are mirror images of those seen in the In section.
Smooth In Smooth Out creates a smooth transition of action through the key.
Linear In Linear Out creates a direct linear action through the key, with no attempt to smooth the transition.
Step In and Out is used to create the effect of something turning on or off. You use this to animate the bug's eye blink, in which the eye is open and then remains shut for a few frames and then is open again.
Fast In Fast Out changes the animation on both sides of the keyframe. Used on the In side, it enables you to accelerate as you approach the key. Used on the Out side, the animation will start out slowly and accelerate as it leaves the key.
Slow In Slow Out changes the animation on both sides of the keyframe, enabling you to decelerate as you approach the key on the In side and slowly accelerate away from the key on the Out side.
Custom In and Out is a tangent setting that enables you to use Be´zier handles in the Track View Function Curves display to create custom animation curves for your animation.