function ExtrudeGeometry( shapes, options ) {

		if ( typeof( shapes ) === "undefined" ) {

			shapes = [];
			return;

		}

		Geometry.call( this );

		this.type = 'ExtrudeGeometry';

		shapes = Array.isArray( shapes ) ? shapes : [ shapes ];

		this.addShapeList( shapes, options );

		this.computeFaceNormals();

		// can't really use automatic vertex normals
		// as then front and back sides get smoothed too
		// should do separate smoothing just for sides

		//this.computeVertexNormals();

		//console.log( "took", ( Date.now() - startTime ) );

	}
@author zz85 / http://www.lab4games.net/zz85/blog

Creates extruded geometry from a path shape.

parameters = {

 curveSegments: <int>, // number of points on the curves
 steps: <int>, // number of points for z-side extrusions / used for subdividing segments of extrude spline too
 amount: <int>, // Depth to extrude the shape

 bevelEnabled: <bool>, // turn on bevel
 bevelThickness: <float>, // how deep into the original shape bevel goes
 bevelSize: <float>, // how far from shape outline is bevel
 bevelSegments: <int>, // number of bevel layers

 extrudePath: <THREE.Curve> // curve to extrude shape along
 frames: <Object> // containing arrays of tangents, normals, binormals

 uvGenerator: <Object> // object that provides UV generator functions

}