fix plane in gui

gui/js/UI.Viewport.js

@@ -53,6 +53,8 @@ UI.Viewport = function () {
 
 	var _plane = new THREE.Mesh( new THREE.PlaneGeometry( 2000, 2000, 8, 8 ), new THREE.MeshBasicMaterial( { color: 0x000000, opacity: 0.25, transparent: true, wireframe: true } ) );
 	_plane.visible = false;
+	_plane.geometry.applyMatrix( new THREE.Matrix4().makeRotationX( Math.PI / 2 ) );
+
 	_sceneHelpers.add( _plane );
 
 	var _projector = new THREE.Projector();