PrefabCreator.cs

using UnityEditor;
using UnityEngine;
using System.Collections.Generic;
using System.IO;

public class PrefabCreator : EditorWindow
{
    const string MenuPath = "Assets/Create/CreatePrefab #\\";

    readonly static string[] ColliderName =
    {
        "FUC_Box",
        "FUC_Sphere",
    };

    delegate void AddCollider(GameObject o, int index);

    static readonly AddCollider[] AddColliderMethod =
    {
        new AddCollider(AddBoxCollider),
        new AddCollider(AddSphereCollider),
    };

    /// <summary>
    /// 選択されているアセットのprefabを全て作成する
    /// </summary>
    [MenuItem(MenuPath)]
    static void CreatePrefabs()
    {
        GameObject[] objectArray = Selection.gameObjects;

        List<string> pathList = new List<string>();

        //モデルと同じディレクトリにプレハブを作成するため、パスを取得する
        AddFolderPath(pathList);

        for (int i = 0; i < objectArray.Length; i++)
        {
            string localPath = pathList[i] + ".prefab";

            if (AssetDatabase.LoadAssetAtPath(localPath, typeof(GameObject)))
            {
                if (EditorUtility.DisplayDialog("よろしいですか？",
                    "もうすでにこのプレハブありますよ？上書きしますか？",
                    "はい",
                    "いいえ"))
                {
                    CreateNewPrefab(objectArray[i], localPath);
                }

                continue;
            }

            Debug.Log(objectArray[i].name + "をColliderコンポーネントを追加してプレハブ化しました。");
            CreateNewPrefab(objectArray[i], localPath);
        }
    }

    static void AddFolderPath(List<string> pathList)
    {
        foreach (var files in Selection.assetGUIDs)
        {
            var path = AssetDatabase.GUIDToAssetPath(files);
            var extension = Path.GetExtension(path);

            path = path.Replace(extension, string.Empty);

            pathList.Add(path);
        }
    }

    static void CreateNewPrefab(GameObject obj, string localPath)
    {
        GameObject prefab = PrefabUtility.CreatePrefab(localPath, obj);
        GameObject o = PrefabUtility.ReplacePrefab(obj, prefab, ReplacePrefabOptions.ConnectToPrefab);

        for (int i = 0; i < ColliderName.Length; i++)
        {
            if (o.transform.Find(ColliderName[i]))
            {
                AddColliderMethod[i](o, i);
                break;
            }
        }
    }

    static void AddBoxCollider(GameObject o, int index)
    {
        o.AddComponent<BoxCollider>();

        Transform colliderTransform = o.transform.Find(ColliderName[index]);

        (o.GetComponent<Collider>() as BoxCollider).center = colliderTransform.position;
        (o.GetComponent<Collider>() as BoxCollider).size = colliderTransform.localScale;

        //当たり判定作成用のメッシュは不要になったので削除する
        DestroyImmediate(o.transform.Find(ColliderName[index]).gameObject, true);
    }

    static void AddSphereCollider(GameObject o, int index)
    {
        o.AddComponent<SphereCollider>();

        Transform colliderTransform = o.transform.Find(ColliderName[index]);

        (o.GetComponent<Collider>() as SphereCollider).center = colliderTransform.position;
        (o.GetComponent<Collider>() as SphereCollider).radius = colliderTransform.localScale.x;

        //当たり判定作成用のメッシュは不要になったので削除する
        DestroyImmediate(o.transform.Find(ColliderName[index]).gameObject, true);
    }

    [MenuItem(MenuPath, true)]
    static bool ValidateCreatePrefab()
    {
        return Selection.activeGameObject != null;
    }
}