Replace with Prefab script

3d Prototyp/Assets/Editor/ReplaceWithPrefab.cs

@@ -0,0 +1,57 @@
+using UnityEngine;
+using UnityEditor;
+
+public class ReplaceWithPrefab : EditorWindow
+{
+    [SerializeField] private GameObject prefab;
+
+    [MenuItem("Tools/Replace With Prefab")]
+    static void CreateReplaceWithPrefab()
+    {
+        EditorWindow.GetWindow<ReplaceWithPrefab>();
+    }
+
+    private void OnGUI()
+    {
+        prefab = (GameObject)EditorGUILayout.ObjectField("Prefab", prefab, typeof(GameObject), false);
+
+        if (GUILayout.Button("Replace"))
+        {
+            var selection = Selection.gameObjects;
+
+            for (var i = selection.Length - 1; i >= 0; --i)
+            {
+                var selected = selection[i];
+                var prefabType = PrefabUtility.GetPrefabType(prefab);
+                GameObject newObject;
+
+                if (prefabType == PrefabType.Prefab)
+                {
+                    newObject = (GameObject)PrefabUtility.InstantiatePrefab(prefab);
+                }
+                else
+                {
+                    newObject = Instantiate(prefab);
+                    newObject.name = prefab.name;
+                }
+
+                if (newObject == null)
+                {
+                    Debug.LogError("Error instantiating prefab");
+                    break;
+                }
+
+                Undo.RegisterCreatedObjectUndo(newObject, "Replace With Prefabs");
+                newObject.transform.parent = selected.transform.parent;
+                newObject.transform.localPosition = selected.transform.localPosition;
+                newObject.transform.localRotation = selected.transform.localRotation;
+                newObject.transform.localScale = selected.transform.localScale;
+                newObject.transform.SetSiblingIndex(selected.transform.GetSiblingIndex());
+                Undo.DestroyObjectImmediate(selected);
+            }
+        }
+
+        GUI.enabled = false;
+        EditorGUILayout.LabelField("Selection count: " + Selection.objects.Length);
+    }
+}