 		 * @param replace Whether to replace existing normals or tangents data.
 		 * 
 		 */
-		public function computeTangentSpace(streamUsage : int = -1) : Geometry
+		public function computeTangentSpace(computeNormals : Boolean = true, streamUsage : int = -1) : Geometry
 		{
 			var numStreams		: uint			= this.numVertexStreams;
 			var indices			: Vector.<uint>	= indexStream.lock();

							new Vector.<Number>(numVertices * 6)
						);
					}
					else if (!hasNormals)
					{
						normalsStream = new VertexStream(
							streamUsage,

						);
					}
					
					if (computeNormals)
						fillNormalsData(indices, normalsStream, xyzStream, numVertices);
					
					fillTangentsData(indices, tangentsStream, xyzStream, uvStream, numVertices);
					
					if (!hasNormals)
