Drop Selected Model To Ground(or closest model below) (No Colliders Needed)

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

public class EditorMenuItems : MonoBehaviour
{
        [MenuItem("GameObject/Set Object On Ground - No Collider #G", false, 10)]
        private static void SetObjectOnGround()
        {
            GameObject selection  = Selection.activeGameObject;
            Transform[] allObjects = UnityEngine.Object.FindObjectsOfType<Transform>() ;
            //Try to find the objects that are closest to the current GO
            IEnumerable<Transform> closeObjects = allObjects.Where(o =>  o.position.y < selection.transform.position.y 
                                                     && o.gameObject != selection.gameObject
                                                     && o.GetComponent<MeshRenderer>() 
                                                     && PointContainedIn2DPlane(selection.transform.position, o.GetComponent<MeshRenderer>().bounds));

            Vector3 hitPoint = Vector3.zero;
            float closestDist = 10000;
            foreach (Transform closeObject in closeObjects)
            {
                RaycastHit hit = new RaycastHit();
                bool bHit = HandleUtilityWrapper.IntersectRayMesh(new Ray(selection.transform.position, Vector3.down), closeObject.GetComponent<MeshFilter>(), out hit);
                if (!bHit)
                {
                    continue;
                }
                if (hit.distance < closestDist)
                {
                    // Debug.Log($"Updating Closest: {closeObject.name} dist:{hit.distance}");
                    hitPoint = hit.point;
                    closestDist = hit.distance;
                }
            }

            Vector3 position = selection.transform.position;
            position = new Vector3(position.x, hitPoint.y, position.z);
            selection.transform.position = position;
        }

        private static bool PointContainedIn2DPlane(Vector3 point, Bounds bounds)
        {
            if ((point.x > bounds.min.x && point.x < bounds.max.x) && (point.z > bounds.min.z && point.z < bounds.max.z))
            {
                return true;
            }

            return false;
        }
}

using System;
using System.Reflection;
using UnityEngine;
using UnityEditor;
using System.Linq;
 
// Allows for access to Unity function that they haven't made public (through reflection)
// Makes it so we can do mesh raycasting (no colliders)
[InitializeOnLoad]
    public static class HandleUtilityWrapper
    {
        private static readonly Type       HandleUtility;
        private static readonly MethodInfo IntersectRayMeshMethodInfo;
 
        static HandleUtilityWrapper()
        {
            var editorTypes = typeof(Editor).Assembly.GetTypes();
            HandleUtility              = editorTypes.FirstOrDefault(t => t.Name == "HandleUtility");
            IntersectRayMeshMethodInfo = HandleUtility.GetMethod("IntersectRayMesh", BindingFlags.Static | BindingFlags.NonPublic);
        }
 
        public static bool IntersectRayMesh(Ray ray, MeshFilter meshFilter, out RaycastHit hit)
        {
            return IntersectRayMesh(ray, meshFilter.sharedMesh, meshFilter.transform.localToWorldMatrix, out hit);
        }
 
        private static object[] _parms = new object[4];
 
        public static bool IntersectRayMesh(Ray ray, Mesh mesh, Matrix4x4 matrix, out RaycastHit hit)
        {
            _parms[0] = ray;
            _parms[1] = mesh;
            _parms[2] = matrix;
            _parms[3] = null;
 
            var result = (bool) IntersectRayMeshMethodInfo.Invoke(null, _parms);
            hit = (RaycastHit) _parms[3];
            return result;
        }
    }