diff --git a/src/core/Geometry.js b/src/core/Geometry.js
index 75fd92df791c20beea558f330d93bfe9413a0b75..4f9f4a4813ea439196b6c076a5776755dfb35a0b 100644
--- a/src/core/Geometry.js
+++ b/src/core/Geometry.js
@@ -1046,9 +1046,19 @@ THREE.Geometry.prototype = {
 
 	},
 
-	clone: function () {
+	clone: function ( geometry ) {
 
-		var geometry = new THREE.Geometry();
+		if ( geometry === undefined ) {
+
+			geometry = new THREE.Geometry();
+
+		} else {
+
+			geometry.vertices = [];
+			geometry.faces = [];
+			geometry.faceVertexUvs = [ [] ];
+
+		}
 
 		var vertices = this.vertices;