选择物体生成Prefab

// Creates a prefab at the given path.
// If a prefab already exists it asks if you want to replace it

using UnityEngine;
using UnityEditor;

public class CreateNewPrefab : EditorWindow
{
    [MenuItem("Prefab/Create New Prefab")]
    static void CreatePrefab()
    {
        GameObject[] objs = Selection.gameObjects;

        foreach (GameObject go in objs)
        {
            string localPath = "Assets/" + go.name + ".prefab";
            if (AssetDatabase.LoadAssetAtPath(localPath, typeof(GameObject)))
            {
                if (EditorUtility.DisplayDialog("Are you sure?",
                    "The prefab already exists. Do you want to overwrite it?",
                    "Yes",
                    "No"))
                {
                    CreateNew(go, localPath);
                }
            }
            else
            {
                Debug.Log(go.name + " Prefab Created");
                CreateNew(go, localPath);
            }
        }
    }

    // Disable the menu item if no selection is in place
    [MenuItem("Prefab/Create New Prefab", true)]
    static bool ValidateCreatePrefab()
    {
        return Selection.activeGameObject != null;
    }

    static void CreateNew(GameObject obj, string localPath)
    {
        Object prefab = PrefabUtility.CreateEmptyPrefab(localPath);
        PrefabUtility.ReplacePrefab(obj, prefab, ReplacePrefabOptions.ConnectToPrefab);
    }
}