function Cylindrical( radius, theta, y ) {

		this.radius = ( radius !== undefined ) ? radius : 1.0; // distance from the origin to a point in the x-z plane
		this.theta = ( theta !== undefined ) ? theta : 0; // counterclockwise angle in the x-z plane measured in radians from the positive z-axis
		this.y = ( y !== undefined ) ? y : 0; // height above the x-z plane

		return this;

	}
@author Mugen87 / https://github.com/Mugen87

Ref: https://en.wikipedia.org/wiki/Cylindrical_coordinate_system