code: function( geometry ) {
  
  		var vertices = [];
  
  		for ( var i = 0, il = geometry.faces.length; i < il; i ++ ) {
  
  			var n = vertices.length;
  
  			var face = geometry.faces[ i ];
  
  			if ( face instanceof THREE.Face4 ) {
  
  				var a = face.a;
  				var b = face.b;
  				var c = face.c;
  				var d = face.d;
  
  				var va = geometry.vertices[ a ];
  				var vb = geometry.vertices[ b ];
  				var vc = geometry.vertices[ c ];
  				var vd = geometry.vertices[ d ];
  
  				vertices.push( va.clone() );
  				vertices.push( vb.clone() );
  				vertices.push( vc.clone() );
  				vertices.push( vd.clone() );
  
  				face.a = n;
  				face.b = n + 1;
  				face.c = n + 2;
  				face.d = n + 3;
  
  			} else {
  
  				var a = face.a;
  				var b = face.b;
  				var c = face.c;
  
  				var va = geometry.vertices[ a ];
  				var vb = geometry.vertices[ b ];
  				var vc = geometry.vertices[ c ];
  
  				vertices.push( va.clone() );
  				vertices.push( vb.clone() );
  				vertices.push( vc.clone() );
  
  				face.a = n;
  				face.b = n + 1;
  				face.c = n + 2;
  
  			}
  
  		}
  
  		geometry.vertices = vertices;
  		delete geometry.__tmpVertices;
  
  	}
docs: Make all faces use unique vertices so that each face can be separated from others