Method Sphere

src/examples/csg_primitive.cpp:67–69

		  a(la), b(lb), c(lc) {}
public:
	static Node Sphere(double r) {
		return Node(PRIM_SPHERE, r);
	}
	static Node Box(double dx, double dy, double dz) {
		return Node(PRIM_BOX, dx, dy, dz);
	}