Applications in computer graphics and computer-aided design (CAD) require the rapid generation of smooth curves that can be quickly and conveniently modified.
For reasons of aesthetics and computational expense, we do not want the entire shape of the curve to be affected by small local changes.
（图片来自百度百科）
Bézier curve的应用：
photoshop：
图片来自百度百科：
原文：http://www.cnblogs.com/gcczhongduan/p/4551766.html