5.2 挤压与拉伸 Stretch and Squash

Q：下列图中的动作有何共性？

       What commonalities the following actions have?

在动画的世界里，任何一个物体都可以有形变，挤压与拉伸是最基本的夸张手法。

In the world of animation, any object can be deformed.

挤压与拉伸的目的，是给所画物体添加重量感和灵活感。

The purpose of squash and stretch is to give a sense of weight and flexibility to drawn objects.

它可以应用于简单的物体，比如一个弹跳的球，也可以应用于更复杂的结构，比如人脸的肌肉组织。如果把一个人挤压或拉伸到夸张的程度，会产生一种滑稽效果。

It can be applied to simple objects, like a bouncing ball, or more complex constructions, like the musculature of a human face. Taken to an extreme, a figure stretched or squashed to an exaggerated degree can have a comical effect.

单纯的移动过程会使图形显得相当死板和生硬。在现实生活中，这种状态只会发生在例如椅子、碟子和盘子这些较硬的无生命的物体上。

如果一个物体掉在地上，它与地面碰撞时的形状是被压扁的；如果它被向上弹起，那么，它的形状又会得到伸展。

If an object falls to the ground, its shape is squashed when it collides with the ground. If it bounces up, then its shape will stretch out again.

但无论是被挤压还是伸展，它的体积是不会改变的。

The most important aspect of this principle is that an object's volume does not change when squashed or stretched.

在角色快速、大幅度运动时，一定要有夸张的肢体拉伸变形。

If the character is moving fast, there must be exaggerated limb stretching.

但是慢、小幅度运动，可以小幅度拉伸变形或者不变形。

But not be slow and small range of motion.

肢体的极度夸张变形，多在艺术短片里运用，用来表达特殊的含义。

The extreme exaggeration and deformation of limbs are mostly used in short art animated films to express special meanings.

作业：小球原地循环跳 Bouncing ball (loop)

要求Requirement

1. 循环跳 Jumping loop

2. 表现出小球的重量Show its weight

3. 小球可以有自己的个性Show it personality

4. 用到挤压、拉伸、变形等夸张手法Squash and stretch

5. 尝试不同的滞空时长和触地时长，所表现的不同运动。

    Try different timing of staying in the air and contact on the ground.

6. 尝试有触地瞬间的那张，和无接触地瞬间的那张，所表现的不同运动。

    Try to add one frame just contact on the ground or not.