PlaneGeometry inherits from Geometry

src/extras/geometries/PlaneGeometry.js

@@ -81,8 +81,9 @@ THREE.PlaneGeometry = function ( width, height, widthSegments, heightSegments )
 
 	}
 
+	THREE.Geometry.call( this );
 	THREE.IndexedGeometry2.call( this, indices, vertices, normals, uvs );
 
 };
 
-THREE.PlaneGeometry.prototype = Object.create( THREE.IndexedGeometry2.prototype );
+THREE.PlaneGeometry.prototype = Object.create( THREE.Geometry.prototype );