Transfer partial Terrain Tree into Prefab and can still revert back to Terrain Tree to edit.

把部分Terrain Tree轉成Prefab物件，而且還是可以還原回Terrain Tree來繼續編輯

Code

<aside> 💡 Put this script in Editor folder

</aside>

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

public class TerrainTreeGenerator : EditorWindow
{
    private float heightFudge;
    private float scaleMax = 1.5f;

    private float scaleMin = .9f;

    private bool sortingByPrefab;
    private bool[] prefabToggles = new bool[0];

    private Terrain _terrain;

    public Terrain terrain
    {
        get { return _terrain; }
        set
        {
            if (_terrain != value)
                prefabToggles = new bool[value.terrainData.treePrototypes.Length];
            _terrain = value;
        }
    }

    private int treeDivisions = 5;

    private void OnGUI()
    {
        // The actual window code goes here
        GUILayout.Label("Replace Trees with Prefabs", EditorStyles.boldLabel);

        terrain = EditorGUILayout.ObjectField("Terrain:", terrain, typeof(Terrain), true) as Terrain;

        GUILayout.Label("Convert By Prefab or Grid(will convert all detail)");
        sortingByPrefab = GUILayout.Toggle(sortingByPrefab, "By Prefab");
        GUILayout.Space(10f);
        if (!sortingByPrefab)
        {
            GUILayout.Label("Tree groups " + treeDivisions);
            treeDivisions = (int)GUILayout.HorizontalSlider(treeDivisions, 1, 10);
            GUILayout.Space(10f);
        }
        else
        {
            for (int i = 0; i < prefabToggles.Length; i++)
            {
                prefabToggles[i] = GUILayout.Toggle(prefabToggles[i], terrain.terrainData.treePrototypes[i].prefab.name);
            }
        }

        GUILayout.Label("Tree small scale " + scaleMin);
        scaleMin = GUILayout.HorizontalSlider(scaleMin, .5f, 1f);
        GUILayout.Space(10f);

        GUILayout.Label("Tree large scale " + scaleMax);
        scaleMax = GUILayout.HorizontalSlider(scaleMax, 1f, 3f);
        GUILayout.Space(10f);

        GUILayout.Label("Height fudge " + heightFudge);
        heightFudge = GUILayout.HorizontalSlider(heightFudge, -2f, 2f);
        GUILayout.Space(20f);

        if (GUILayout.Button("Replace trees!")) Convert();
    }

    [MenuItem("Tools/Terrain Tree Generator")]
    public static void ShowWindow()
    {
        GetWindow(typeof(TerrainTreeGenerator));
    }

    private static GameObject CreateBlankPrefab(TreePrototype prototype)
    {
        GameObject go = new GameObject();
        PrefabUtility.SaveAsPrefabAsset(go, AssetDatabase.GetAssetPath(prototype.prefab).Replace(".prefab", "_blank.prefab"));
        DestroyImmediate(go);
        return AssetDatabase.LoadAssetAtPath<GameObject>(AssetDatabase.GetAssetPath(prototype.prefab).Replace(".prefab", "_blank.prefab"));
    }

    public void Convert()
    {
        if (terrain == null)
            return;

        var data = terrain.terrainData;

        var treeParent = new GameObject("Trees");
        var treegroups = new List<List<Transform>>();
        var treegroup = new List<Transform>();

        if (sortingByPrefab)
            for (var i = 0; i < data.treePrototypes.Length; i++)
            {
                var t = new GameObject(terrain.terrainData.treePrototypes[i].prefab.name + "_Group");
                t.transform.parent = treeParent.transform;
                treegroup.Add(t.transform);
            }
        else
            for (var i = 0; i < treeDivisions; i++)
            {
                treegroups.Add(new List<Transform>());
                for (var j = 0; j < treeDivisions; j++)
                {
                    var treeGroup = new GameObject("TreeGroup_" + i + "_" + j);
                    treeGroup.transform.parent = treeParent.transform;
                    treegroups[i].Add(treeGroup.transform);
                }
            }

        var width = data.size.x;
        var height = data.size.z;
        var y = data.size.y;

        var xDiv = data.size.x / treeDivisions;
        var zDiv = data.size.z / treeDivisions;

        foreach (var tree in data.treeInstances)
        {
            if (sortingByPrefab)
            {
                if (!prefabToggles[tree.prototypeIndex])
                    continue;
            }

            var position = new Vector3(tree.position.x * width, tree.position.y * y, tree.position.z * height);

            var xGroup = (int)(position.x / xDiv);
            var zGroup = (int)(position.z / zDiv);

            position += terrain.transform.position;

            var scale = Random.Range(scaleMin, scaleMax);
            position.y += heightFudge;

            var newTree = (GameObject)PrefabUtility.InstantiatePrefab(data.treePrototypes[tree.prototypeIndex].prefab);
            newTree.transform.SetPositionAndRotation(position, Quaternion.Euler(Random.Range(0f, 360f) * Vector3.up));
            newTree.transform.localScale = scale * Vector3.one;

            if (sortingByPrefab)
                newTree.transform.SetParent(treegroup[tree.prototypeIndex]);
            else
                newTree.transform.SetParent(treegroups[xGroup][zGroup]);
        }
        if (sortingByPrefab)
        {
            TreePrototype[] prototypes = data.treePrototypes;
            for (int i = 0; i < prefabToggles.Length; i++)
            {
                if (prefabToggles[i] && !prototypes[i].prefab.name.Contains("_blank"))
                    prototypes[i].prefab = CreateBlankPrefab(data.treePrototypes[i]);
            }
            data.treePrototypes = prototypes;
        }
        else
            terrain.drawTreesAndFoliage = false;
    }
}

How To Convert?

1. Go to Tools/Terrain Tree Generator.

   

2. By Prefab on: convert only SELECTED tree prefab and sorting by prefab.

   By Prefab off: convert ALL trees and sorting by space grid.

3. Set random value (scale, height)

   

4. Press button, Trees will be generated in scene.

Convert by Prefab

Convert by Grid

How To Revert?

Convert By Prefab

The code generate a blank prefab to replace converted terrain tree so that they won't draw twice. Just assign original prefab back and you can keep edit this tree.

這個Code會產生一個空的Prefab來取代Terrain Tree指定的Prefab，這樣一來他就不會重複畫同一棵樹，你只要把原本的Prefab指定回來就可以繼續編輯

Convert By Grid