Cleanup TreePrototypes list of terrain with small script

Once, I need to remove all TreePrototypes which was not used. I did it with this script:

Code (csharp):

1.  
2. using UnityEngine;
3. using UnityEditor;
4. using System.Collections;
5. using System.Collections.Generic;
6.  
7. // By ValeryAlex (hww)
8.  
9. public class CleanupTreePrototypes : ScriptableObject
10. {
11.  
12.     [MenuItem ("Tools/Terrain/Cleanup Unused Trees")]
13.     static void MenuAddChild()
14.     {
15.        
16.         Terrain terrain = GameObject.FindObjectOfType(typeof(Terrain)) as Terrain;
17.         Debug.Log("Found terrain " + terrain.name);
18.        
19.         TerrainData terrainData = terrain.terrainData;
20.        
21.         Dictionary<int,int> list = new Dictionary<int,int>() ;
22.         for (int i = 0; i<terrainData.treePrototypes.Length; i++) {
23.             list[i] = 0;
24.         }
25.         foreach (TreeInstance treeInstance in terrainData.treeInstances) {
26.                 list[treeInstance.prototypeIndex] += 1;
27.         }
28.        
29.         int cnt = 0;
30.         List<TreePrototype> protos = new List<TreePrototype>();
31.         string str = "";
32.         for (int i = 0; i<list.Count; i++) {
33.            
34.             str += i.ToString() + " " + list[i].ToString() + "\n";
35.  
36.  
37.             if (list[i]==0)
38.                 list[i]=-1;
39.             else {
40.                 protos.Add(terrainData.treePrototypes[i]);
41.                 list[i] = cnt++;
42.             }
43.         }
44.        
45.         Debug.Log(str);
46.        
47.         List<TreeInstance> trees = new List<TreeInstance>();
48.        
49.         foreach (TreeInstance treeInstance in terrainData.treeInstances) {
50.             TreeInstance tree = treeInstance;
51.             tree.prototypeIndex = list[tree.prototypeIndex];
52.             trees.Add(tree);
53.         }
54.        
55.        
56.         terrainData.treeInstances = trees.ToArray();
57.         terrainData.treePrototypes = protos.ToArray();
58.  
59.  
60.         terrainData.RefreshPrototypes();
61.         terrain.Flush();
62.     }
63. }
64.  

Maybe there is better solution... I do not know. Anyway maybe this piece of code will be helpful to anybody.

P.S. Backup your level before try this script :!:

 

Thanks for this!