PhysicsSimulation v2

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

public class PhysicsSimulation: Editor {

    public static int maxIterations = 1000;
    private static SimulatedBody[] simulatedBodies;
    private static List<Rigidbody> selectedRigidbodies = new List<Rigidbody>();

    private static List<Rigidbody> generatedRigidbodies;
    private static List<Collider> generatedColliders;

    [MenuItem("Tools/Physics Simulation/Run Simulation _g")]
    public static void RunSimulation() {
        selectedRigidbodies.Clear();

        foreach (GameObject i in Selection.gameObjects) {
            Undo.RecordObject(i.transform, "Physics Simulation");
        }

        AutoGenerateComponents();

        foreach (GameObject i in Selection.gameObjects) {
            if (i.GetComponent<Rigidbody>()) {
                selectedRigidbodies.Add(i.GetComponent<Rigidbody>());
            }
        }

        simulatedBodies = FindObjectsOfType<Rigidbody>().Select(rb => new SimulatedBody(rb, selectedRigidbodies.Contains(rb))).ToArray();

        Physics.autoSimulation = false;
        for (int i = 0; i < maxIterations; i++){
            Physics.Simulate(Time.fixedDeltaTime);
            if (simulatedBodies.All(body => body.rigidBody.IsSleeping() || !body.isSelected)) {
                Debug.Log("Total Iterations: " + i);
                break;
            }
        }
        Physics.autoSimulation = true;

        foreach (SimulatedBody body in simulatedBodies) {
            if (!body.isSelected) {
                body.Reset();
            }
        }

        RemoveAutoGeneratedComponents();
    }

    [MenuItem("Tools/Physics Simulation/Run Simulation _g", true)]
    public static bool ValidateRunSimulation() {
        if (EditorWindow.focusedWindow.titleContent.text == "Scene") {
            return true;
        }
        EditorWindow.focusedWindow.SendEvent(Event.KeyboardEvent("g"));
        return false;
    }

    private static void AutoGenerateComponents() {
        generatedRigidbodies = new List<Rigidbody>();
        generatedColliders = new List<Collider>();

        foreach (GameObject i in Selection.gameObjects) {
            if (!i.GetComponent<Rigidbody>()) {
                generatedRigidbodies.Add(i.AddComponent<Rigidbody>());
            }
            if (!i.GetComponent<Collider>()) {
                generatedColliders.Add(i.AddComponent<BoxCollider>());
            }
            else {
                if (i.GetComponent<MeshCollider>()) {
                    i.GetComponent<MeshCollider>().convex = true;
                }
            }
        }
    }

    private static void RemoveAutoGeneratedComponents() {
        foreach (Rigidbody rb in generatedRigidbodies) {
            DestroyImmediate(rb);
        }
        foreach (Collider c in generatedColliders) {
            DestroyImmediate(c);
        }
    }

    [MenuItem("Tools/Physics Simulation/Find Objects Under -1000")]
    public static void CheckForGameobjectsBelow1000() {
        int objectCount = 0;
        GameObject[] allObjects = UnityEngine.Object.FindObjectsOfType<GameObject>();
        foreach (GameObject go in allObjects) {
            if (go.activeInHierarchy) {
                if (go.transform.position.y < -1000f) {
                    objectCount++;
                    Debug.Log("GameObject below -1000: " + go.name);
                }
            }
        }
        Debug.Log("Total Gameobjects below -1000: " + objectCount);
    }

    [MenuItem("Tools/Physics Simulation/Reset Previous Simulation")]
    public static void ResetAllBodies() {
        if (simulatedBodies != null) {
            foreach (SimulatedBody body in simulatedBodies) {
                body.Reset();
            }
        }
    }

    struct SimulatedBody {
        public readonly Rigidbody rigidBody;
        public readonly bool isSelected;
        readonly Vector3 originalPosition;
        readonly Quaternion originalRotation;
        readonly Transform transform;

        public SimulatedBody(Rigidbody rigidBody, bool isSelected){
            this.rigidBody = rigidBody;
            this.isSelected = isSelected;
            transform = rigidBody.transform;
            originalPosition = rigidBody.position;
            originalRotation = rigidBody.rotation;
        }

        public void Reset() {
            transform.position = originalPosition;
            transform.rotation = originalRotation;
            if (rigidBody != null) {
                rigidBody.velocity = Vector3.zero;
                rigidBody.angularVelocity = Vector3.zero;
            }
        }
    }
}