.cs

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

public class OptimizeScene : MonoBehaviour
{
    public int maxCnt=50;
    public GPUInstancerPrefabManager prefabManager;
    Dictionary<string, Proto> prototypes = new Dictionary<string, Proto>();
    public void Start()
    {
        var trs = FindObjectsOfType<Transform>();

        foreach (var tr in trs)
        {
            if (tr.GetComponent<DisableRenderer>())
            {
                DestroyImmediate(tr.GetComponent<MeshRenderer>());
                DestroyImmediate(tr.GetComponent<MeshFilter>());
                DestroyImmediate(tr.GetComponent<DisableRenderer>());
            }

            var mf = tr.GetComponent<MeshFilter>();
            var lodGroup = tr.GetComponent<LODGroup>();
            var meshRenderer = tr.GetComponent<MeshRenderer>();
            if (lodGroup || mf && mf.sharedMesh && meshRenderer)
            {
                //if (!lodGroup)
                //    //if (meshRenderer.bounds.size.magnitude < 10)
                //    {
                //        var lg = tr.gameObject.AddComponent<LODGroup>();
                //        lg.SetLODs(new LOD[1] { new LOD(.1f, new[] { meshRenderer }) });
                //    }

                string key = lodGroup ? lodGroup.size.ToString() : mf.sharedMesh.name;

                if (!tr.parent || !tr.parent.GetComponentInParent<LODGroup>() || lodGroup)
                {
                    Proto val;
                    if (!prototypes.TryGetValue(key, out val))
                    {
                        //var pr = GPUInstancerAPI.DefineGameObjectAsPrefabPrototypeAtRuntime(prefabManager, tr.gameObject);
                        //if (pr)
                        //    pr.isFrustumCulling= pr.isOcclusionCulling = false;
                        //pr.maxDistance = 10;
                        val = prototypes[key] = new Proto() { /*a = pr */};
                    }
                    val.instances.Add(tr.gameObject);
                }

                //if (meshRenderer)
                //    meshRenderer.enabled = false;
                //if (lodGroup)
                //    lodGroup.enabled = false;
                //tr.gameObject.SetActive(false);
                //tr.name = key;
            }
        }

        foreach (var a in prototypes)
        {

            print(a.Key + " " + a.Value.instances.Count);
            if (a.Value.instances.Count > maxCnt)
            {
                var pr = GPUInstancerAPI.DefineGameObjectAsPrefabPrototypeAtRuntime(prefabManager, a.Value.instances[0].gameObject);
                if (pr != null)
                    GPUInstancerAPI.AddInstancesToPrefabPrototypeAtRuntime(prefabManager, pr, a.Value.instances);
            }

            //else
            //    foreach (var g in a.Value.instances)
            //    {
            //        var mr = g.GetComponent<MeshRenderer>();
            //        if (mr && mr.bounds.size.magnitude < 10)
            //        {
            //            var lg = g.AddComponent<LODGroup>();
            //            lg.SetLODs(new LOD[1] { new LOD(.5f, new[] { mr }) });
            //        }
            //    }
        }

    }
}

public class Proto
{
    //public GPUInstancerPrefabPrototype a;
    public List<GameObject> instances = new List<GameObject>();
}