Visual Computing(可视计算)

需要关注一下的是Curve、CurvePath、Path及Shape类之间的继承、组合关系.  其中拉伸体ExtrudeGeometry需要的截面及路径源于上述继承体系. 

Object3D is the base class for most objects in three.js and provides a set of properties and methods for manipulating objects in 3D space. Note that this can be used for grouping objects via the .add(...