function EdgesGeometry( geometry, thresholdAngle ) {

		BufferGeometry.call( this );

		this.type = 'EdgesGeometry';

		this.parameters = {
			thresholdAngle: thresholdAngle
		};

		thresholdAngle = ( thresholdAngle !== undefined ) ? thresholdAngle : 1;

		// buffer

		var vertices = [];

		// helper variables

		var thresholdDot = Math.cos( _Math.DEG2RAD * thresholdAngle );
		var edge = [ 0, 0 ], edges = {};
		var key, keys = [ 'a', 'b', 'c' ];

		// prepare source geometry

		var geometry2;

		if ( geometry.isBufferGeometry ) {

			geometry2 = new Geometry();
			geometry2.fromBufferGeometry( geometry );

		} else {

			geometry2 = geometry.clone();

		}

		geometry2.mergeVertices();
		geometry2.computeFaceNormals();

		var sourceVertices = geometry2.vertices;
		var faces = geometry2.faces;

		// now create a data structure where each entry represents an edge with its adjoining faces

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

			var face = faces[ i ];

			for ( var j = 0; j < 3; j ++ ) {

				edge[ 0 ] = face[ keys[ j ] ];
				edge[ 1 ] = face[ keys[ ( j + 1 ) % 3 ] ];
				edge.sort( sortFunction );

				key = edge.toString();

				if ( edges[ key ] === undefined ) {

					edges[ key ] = { index1: edge[ 0 ], index2: edge[ 1 ], face1: i, face2: undefined };

				} else {

					edges[ key ].face2 = i;

				}

			}

		}

		// generate vertices

		for ( key in edges ) {

			var e = edges[ key ];

			// an edge is only rendered if the angle (in degrees) between the face normals of the adjoining faces exceeds this value. default = 1 degree.

			if ( e.face2 === undefined || faces[ e.face1 ].normal.dot( faces[ e.face2 ].normal ) <= thresholdDot ) {

				var vertex = sourceVertices[ e.index1 ];
				vertices.push( vertex.x, vertex.y, vertex.z );

				vertex = sourceVertices[ e.index2 ];
				vertices.push( vertex.x, vertex.y, vertex.z );

			}

		}

		// build geometry

		this.addAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );

		// custom array sort function

		function sortFunction( a, b ) {

			return a - b;

		}

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