几何体

创建常见几何形状：

立方体

THREE.CubeGeometry(width, height, depth, widthSegments, heightSegments, depthSegments) 

球体，半球

THREE.SphereGeometry(radius, segmentsWidth, segmentsHeight, phiStart, phiLength, thetaStart, thetaLength)  

平面（x、y轴所在平面）

THREE.PlaneGeometry(width, height, widthSegments, heightSegments)

圆、扇面（x、y轴所在平面）

THREE.CircleGeometry(radius, segments, thetaStart, thetaLength) 

圆柱（台、锥）

THREE.CylinderGeometry(radiusTop, radiusBottom, height, radiusSegments, heightSegments, openEnded) 
openEnded 表示是否有顶面和底面，缺省值为false，表示有顶面和底面。

正四面体、正八面体、正二十面体

THREE.TetrahedronGeometry(radius, detail)
THREE.OctahedronGeometry(radius, detail)
THREE.IcosahedronGeometry(radius, detail) 

圆环体

THREE.TorusGeometry(radius, tube, radialSegments, tubularSegments, arc)

圆环打结

THREE.TorusKnotGeometry(radius, tube, radialSegments, tubularSegments, p, q, heightScale) 

自定义形状

geometry.vertices.push(new THREE.Vector3(x,y,z));
  ... // 依次增加多个节点
 geometry.faces.push(new THREE.Face3(0,1,2)); // 节点顺序