如何将资源打包成.unity3d文件

using UnityEngine;
using UnityEditor;
using System.Collections;

public class Export{

[MenuItem("Assets/将资源导出成.unity3d文件")]
static void ExportToUnity3d(){
if(Selection.objects.Length>0)
{
string path=EditorUtility.SaveFilePanel("导出资源",null,null,"unity3d");
if(path.Length!=0)BuildPipeline.BuildAssetBundle(Selection.activeObject,Selection.objects,path);
}
else{Debug.Log("请选择要导出的资源或者资源文件夹！");}
}
}