function ExtrudeBufferGeometry( shapes, options ) {

		BufferGeometry.call( this );

		this.type = 'ExtrudeBufferGeometry';

		this.parameters = {
			shapes: shapes,
			options: options
		};

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

		var scope = this;

		var verticesArray = [];
		var uvArray = [];

		for ( var i = 0, l = shapes.length; i < l; i ++ ) {

			var shape = shapes[ i ];
			addShape( shape, options );

		}

		// build geometry

		this.addAttribute( 'position', new Float32BufferAttribute( verticesArray, 3 ) );
		this.addAttribute( 'uv', new Float32BufferAttribute( uvArray, 2 ) );

		this.computeVertexNormals();

		// functions

		function addShape( shape ) {

			var placeholder = [];

			// options

			var curveSegments = options.curveSegments !== undefined ? options.curveSegments : 12;
			var steps = options.steps !== undefined ? options.steps : 1;
			var amount = options.amount !== undefined ? options.amount : 100;

			var bevelEnabled = options.bevelEnabled !== undefined ? options.bevelEnabled : true;
			var bevelThickness = options.bevelThickness !== undefined ? options.bevelThickness : 6;
			var bevelSize = options.bevelSize !== undefined ? options.bevelSize : bevelThickness - 2;
			var bevelSegments = options.bevelSegments !== undefined ? options.bevelSegments : 3;

			var extrudePath = options.extrudePath;

			var uvgen = options.UVGenerator !== undefined ? options.UVGenerator : WorldUVGenerator;

			//

			var extrudePts, extrudeByPath = false;
			var splineTube, binormal, normal, position2;

			if ( extrudePath ) {

				extrudePts = extrudePath.getSpacedPoints( steps );

				extrudeByPath = true;
				bevelEnabled = false; // bevels not supported for path extrusion

				// SETUP TNB variables

				// TODO1 - have a .isClosed in spline?

				splineTube = extrudePath.computeFrenetFrames( steps, false );

				// console.log(splineTube, 'splineTube', splineTube.normals.length, 'steps', steps, 'extrudePts', extrudePts.length);

				binormal = new Vector3();
				normal = new Vector3();
				position2 = new Vector3();

			}

			// Safeguards if bevels are not enabled

			if ( ! bevelEnabled ) {

				bevelSegments = 0;
				bevelThickness = 0;
				bevelSize = 0;

			}

			// Variables initialization

			var ahole, h, hl; // looping of holes

			var shapePoints = shape.extractPoints( curveSegments );

			var vertices = shapePoints.shape;
			var holes = shapePoints.holes;

			var reverse = ! ShapeUtils.isClockWise( vertices );

			if ( reverse ) {

				vertices = vertices.reverse();

				// Maybe we should also check if holes are in the opposite direction, just to be safe ...

				for ( h = 0, hl = holes.length; h < hl; h ++ ) {

					ahole = holes[ h ];

					if ( ShapeUtils.isClockWise( ahole ) ) {

						holes[ h ] = ahole.reverse();

					}

				}

			}


			var faces = ShapeUtils.triangulateShape( vertices, holes );

			/* Vertices */

			var contour = vertices; // vertices has all points but contour has only points of circumference

			for ( h = 0, hl = holes.length; h < hl; h ++ ) {

				ahole = holes[ h ];

				vertices = vertices.concat( ahole );

			}


			function scalePt2( pt, vec, size ) {

				if ( ! vec ) console.error( "THREE.ExtrudeGeometry: vec does not exist" );

				return vec.clone().multiplyScalar( size ).add( pt );

			}

			var b, bs, t, z,
				vert, vlen = vertices.length,
				face, flen = faces.length;


			// Find directions for point movement


			function getBevelVec( inPt, inPrev, inNext ) {

				// computes for inPt the corresponding point inPt' on a new contour
				//   shifted by 1 unit (length of normalized vector) to the left
				// if we walk along contour clockwise, this new contour is outside the old one
				//
				// inPt' is the intersection of the two lines parallel to the two
				//  adjacent edges of inPt at a distance of 1 unit on the left side.

				var v_trans_x, v_trans_y, shrink_by; // resulting translation vector for inPt

				// good reading for geometry algorithms (here: line-line intersection)
				// http://geomalgorithms.com/a05-_intersect-1.html

				var v_prev_x = inPt.x - inPrev.x,
					v_prev_y = inPt.y - inPrev.y;
				var v_next_x = inNext.x - inPt.x,
					v_next_y = inNext.y - inPt.y;

				var v_prev_lensq = ( v_prev_x * v_prev_x + v_prev_y * v_prev_y );

				// check for collinear edges
				var collinear0 = ( v_prev_x * v_next_y - v_prev_y * v_next_x );

				if ( Math.abs( collinear0 ) > Number.EPSILON ) {

					// not collinear

					// length of vectors for normalizing

					var v_prev_len = Math.sqrt( v_prev_lensq );
					var v_next_len = Math.sqrt( v_next_x * v_next_x + v_next_y * v_next_y );

					// shift adjacent points by unit vectors to the left

					var ptPrevShift_x = ( inPrev.x - v_prev_y / v_prev_len );
					var ptPrevShift_y = ( inPrev.y + v_prev_x / v_prev_len );

					var ptNextShift_x = ( inNext.x - v_next_y / v_next_len );
					var ptNextShift_y = ( inNext.y + v_next_x / v_next_len );

					// scaling factor for v_prev to intersection point

					var sf = ( ( ptNextShift_x - ptPrevShift_x ) * v_next_y -
							( ptNextShift_y - ptPrevShift_y ) * v_next_x ) /
						( v_prev_x * v_next_y - v_prev_y * v_next_x );

					// vector from inPt to intersection point

					v_trans_x = ( ptPrevShift_x + v_prev_x * sf - inPt.x );
					v_trans_y = ( ptPrevShift_y + v_prev_y * sf - inPt.y );

					// Don't normalize!, otherwise sharp corners become ugly
					//  but prevent crazy spikes
					var v_trans_lensq = ( v_trans_x * v_trans_x + v_trans_y * v_trans_y );
					if ( v_trans_lensq <= 2 ) {

						return new Vector2( v_trans_x, v_trans_y );

					} else {

						shrink_by = Math.sqrt( v_trans_lensq / 2 );

					}

				} else {

					// handle special case of collinear edges

					var direction_eq = false; // assumes: opposite
					if ( v_prev_x > Number.EPSILON ) {

						if ( v_next_x > Number.EPSILON ) {

							direction_eq = true;

						}

					} else {

						if ( v_prev_x < - Number.EPSILON ) {

							if ( v_next_x < - Number.EPSILON ) {

								direction_eq = true;

							}

						} else {

							if ( Math.sign( v_prev_y ) === Math.sign( v_next_y ) ) {

								direction_eq = true;

							}

						}

					}

					if ( direction_eq ) {

						// console.log("Warning: lines are a straight sequence");
						v_trans_x = - v_prev_y;
						v_trans_y = v_prev_x;
						shrink_by = Math.sqrt( v_prev_lensq );

					} else {

						// console.log("Warning: lines are a straight spike");
						v_trans_x = v_prev_x;
						v_trans_y = v_prev_y;
						shrink_by = Math.sqrt( v_prev_lensq / 2 );

					}

				}

				return new Vector2( v_trans_x / shrink_by, v_trans_y / shrink_by );

			}


			var contourMovements = [];

			for ( var i = 0, il = contour.length, j = il - 1, k = i + 1; i < il; i ++, j ++, k ++ ) {

				if ( j === il ) j = 0;
				if ( k === il ) k = 0;

				//  (j)---(i)---(k)
				// console.log('i,j,k', i, j , k)

				contourMovements[ i ] = getBevelVec( contour[ i ], contour[ j ], contour[ k ] );

			}

			var holesMovements = [],
				oneHoleMovements, verticesMovements = contourMovements.concat();

			for ( h = 0, hl = holes.length; h < hl; h ++ ) {

				ahole = holes[ h ];

				oneHoleMovements = [];

				for ( i = 0, il = ahole.length, j = il - 1, k = i + 1; i < il; i ++, j ++, k ++ ) {

					if ( j === il ) j = 0;
					if ( k === il ) k = 0;

					//  (j)---(i)---(k)
					oneHoleMovements[ i ] = getBevelVec( ahole[ i ], ahole[ j ], ahole[ k ] );

				}

				holesMovements.push( oneHoleMovements );
				verticesMovements = verticesMovements.concat( oneHoleMovements );

			}


			// Loop bevelSegments, 1 for the front, 1 for the back

			for ( b = 0; b < bevelSegments; b ++ ) {

				//for ( b = bevelSegments; b > 0; b -- ) {

				t = b / bevelSegments;
				z = bevelThickness * Math.cos( t * Math.PI / 2 );
				bs = bevelSize * Math.sin( t * Math.PI / 2 );

				// contract shape

				for ( i = 0, il = contour.length; i < il; i ++ ) {

					vert = scalePt2( contour[ i ], contourMovements[ i ], bs );

					v( vert.x, vert.y, - z );

				}

				// expand holes

				for ( h = 0, hl = holes.length; h < hl; h ++ ) {

					ahole = holes[ h ];
					oneHoleMovements = holesMovements[ h ];

					for ( i = 0, il = ahole.length; i < il; i ++ ) {

						vert = scalePt2( ahole[ i ], oneHoleMovements[ i ], bs );

						v( vert.x, vert.y, - z );

					}

				}

			}

			bs = bevelSize;

			// Back facing vertices

			for ( i = 0; i < vlen; i ++ ) {

				vert = bevelEnabled ? scalePt2( vertices[ i ], verticesMovements[ i ], bs ) : vertices[ i ];

				if ( ! extrudeByPath ) {

					v( vert.x, vert.y, 0 );

				} else {

					// v( vert.x, vert.y + extrudePts[ 0 ].y, extrudePts[ 0 ].x );

					normal.copy( splineTube.normals[ 0 ] ).multiplyScalar( vert.x );
					binormal.copy( splineTube.binormals[ 0 ] ).multiplyScalar( vert.y );

					position2.copy( extrudePts[ 0 ] ).add( normal ).add( binormal );

					v( position2.x, position2.y, position2.z );

				}

			}

			// Add stepped vertices...
			// Including front facing vertices

			var s;

			for ( s = 1; s <= steps; s ++ ) {

				for ( i = 0; i < vlen; i ++ ) {

					vert = bevelEnabled ? scalePt2( vertices[ i ], verticesMovements[ i ], bs ) : vertices[ i ];

					if ( ! extrudeByPath ) {

						v( vert.x, vert.y, amount / steps * s );

					} else {

						// v( vert.x, vert.y + extrudePts[ s - 1 ].y, extrudePts[ s - 1 ].x );

						normal.copy( splineTube.normals[ s ] ).multiplyScalar( vert.x );
						binormal.copy( splineTube.binormals[ s ] ).multiplyScalar( vert.y );

						position2.copy( extrudePts[ s ] ).add( normal ).add( binormal );

						v( position2.x, position2.y, position2.z );

					}

				}

			}


			// Add bevel segments planes

			//for ( b = 1; b <= bevelSegments; b ++ ) {
			for ( b = bevelSegments - 1; b >= 0; b -- ) {

				t = b / bevelSegments;
				z = bevelThickness * Math.cos( t * Math.PI / 2 );
				bs = bevelSize * Math.sin( t * Math.PI / 2 );

				// contract shape

				for ( i = 0, il = contour.length; i < il; i ++ ) {

					vert = scalePt2( contour[ i ], contourMovements[ i ], bs );
					v( vert.x, vert.y, amount + z );

				}

				// expand holes

				for ( h = 0, hl = holes.length; h < hl; h ++ ) {

					ahole = holes[ h ];
					oneHoleMovements = holesMovements[ h ];

					for ( i = 0, il = ahole.length; i < il; i ++ ) {

						vert = scalePt2( ahole[ i ], oneHoleMovements[ i ], bs );

						if ( ! extrudeByPath ) {

							v( vert.x, vert.y, amount + z );

						} else {

							v( vert.x, vert.y + extrudePts[ steps - 1 ].y, extrudePts[ steps - 1 ].x + z );

						}

					}

				}

			}

			/* Faces */

			// Top and bottom faces

			buildLidFaces();

			// Sides faces

			buildSideFaces();


			/////  Internal functions

			function buildLidFaces() {

				var start = verticesArray.length / 3;

				if ( bevelEnabled ) {

					var layer = 0; // steps + 1
					var offset = vlen * layer;

					// Bottom faces

					for ( i = 0; i < flen; i ++ ) {

						face = faces[ i ];
						f3( face[ 2 ] + offset, face[ 1 ] + offset, face[ 0 ] + offset );

					}

					layer = steps + bevelSegments * 2;
					offset = vlen * layer;

					// Top faces

					for ( i = 0; i < flen; i ++ ) {

						face = faces[ i ];
						f3( face[ 0 ] + offset, face[ 1 ] + offset, face[ 2 ] + offset );

					}

				} else {

					// Bottom faces

					for ( i = 0; i < flen; i ++ ) {

						face = faces[ i ];
						f3( face[ 2 ], face[ 1 ], face[ 0 ] );

					}

					// Top faces

					for ( i = 0; i < flen; i ++ ) {

						face = faces[ i ];
						f3( face[ 0 ] + vlen * steps, face[ 1 ] + vlen * steps, face[ 2 ] + vlen * steps );

					}

				}

				scope.addGroup( start, verticesArray.length / 3 - start, 0 );

			}

			// Create faces for the z-sides of the shape

			function buildSideFaces() {

				var start = verticesArray.length / 3;
				var layeroffset = 0;
				sidewalls( contour, layeroffset );
				layeroffset += contour.length;

				for ( h = 0, hl = holes.length; h < hl; h ++ ) {

					ahole = holes[ h ];
					sidewalls( ahole, layeroffset );

					//, true
					layeroffset += ahole.length;

				}


				scope.addGroup( start, verticesArray.length / 3 - start, 1 );


			}

			function sidewalls( contour, layeroffset ) {

				var j, k;
				i = contour.length;

				while ( -- i >= 0 ) {

					j = i;
					k = i - 1;
					if ( k < 0 ) k = contour.length - 1;

					//console.log('b', i,j, i-1, k,vertices.length);

					var s = 0,
						sl = steps + bevelSegments * 2;

					for ( s = 0; s < sl; s ++ ) {

						var slen1 = vlen * s;
						var slen2 = vlen * ( s + 1 );

						var a = layeroffset + j + slen1,
							b = layeroffset + k + slen1,
							c = layeroffset + k + slen2,
							d = layeroffset + j + slen2;

						f4( a, b, c, d );

					}

				}

			}

			function v( x, y, z ) {

				placeholder.push( x );
				placeholder.push( y );
				placeholder.push( z );

			}


			function f3( a, b, c ) {

				addVertex( a );
				addVertex( b );
				addVertex( c );

				var nextIndex = verticesArray.length / 3;
				var uvs = uvgen.generateTopUV( scope, verticesArray, nextIndex - 3, nextIndex - 2, nextIndex - 1 );

				addUV( uvs[ 0 ] );
				addUV( uvs[ 1 ] );
				addUV( uvs[ 2 ] );

			}

			function f4( a, b, c, d ) {

				addVertex( a );
				addVertex( b );
				addVertex( d );

				addVertex( b );
				addVertex( c );
				addVertex( d );


				var nextIndex = verticesArray.length / 3;
				var uvs = uvgen.generateSideWallUV( scope, verticesArray, nextIndex - 6, nextIndex - 3, nextIndex - 2, nextIndex - 1 );

				addUV( uvs[ 0 ] );
				addUV( uvs[ 1 ] );
				addUV( uvs[ 3 ] );

				addUV( uvs[ 1 ] );
				addUV( uvs[ 2 ] );
				addUV( uvs[ 3 ] );

			}

			function addVertex( index ) {

				verticesArray.push( placeholder[ index * 3 + 0 ] );
				verticesArray.push( placeholder[ index * 3 + 1 ] );
				verticesArray.push( placeholder[ index * 3 + 2 ] );

			}


			function addUV( vector2 ) {

				uvArray.push( vector2.x );
				uvArray.push( vector2.y );

			}

		}

	}
@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

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

}