Mesh Generation basic

Edit.cs

using UnityEditor;
[CustomEditor(typeof(MapGenerator))]
public class Edit : Editor
{
    public override void OnInspectorGUI()
    {
        base.OnInspectorGUI();
        MapGenerator mapGenerator = (MapGenerator)target;
        mapGenerator.Function();
    }
}

GeneratePlane.cs

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


[RequireComponent(typeof(MeshFilter))]
[RequireComponent(typeof(MeshRenderer))]
public class MapGenerator : MonoBehaviour
{
    public List<Vector3> vertices;
    public Vector2 size;
    [Range(1, 100)]
    public int resolution;
    List<int> triangles;
    Mesh mesh;
    private void Start()
    {
        mesh = GetComponent<MeshFilter>().mesh;
        GeneratePlane();
        AssignMesh();
    }
    public void Function()
    {
        mesh = GetComponent<MeshFilter>().mesh;
        GeneratePlane();
        AssignMesh();
    }
    void GeneratePlane()
    {
        vertices = new List<Vector3>();
        float xPerStep = size.x / resolution;
        float yPerStep = size.y / resolution;
        for (int y = 0; y < resolution + 1; y++)
        {
            for (int x = 0; x < resolution + 1; x++)
            {
                vertices.Add(new Vector3(x * xPerStep, 0, y * yPerStep));
            }
        }

        triangles = new List<int>();

        for (int row = 0; row < resolution; row++)
        {
            for (int column = 0; column < resolution; column++)
            {
                int i = (row * resolution) + column + row;

                // first triangle
                triangles.Add(i);
                triangles.Add(i + resolution + 1);
                triangles.Add(i + resolution + 2);

                // second triangle 

                triangles.Add(i);
                triangles.Add(i + resolution + 2);
                triangles.Add(i + 1);
            }
        }
    }
    void AssignMesh()
    {
        mesh.Clear();
        mesh.vertices = vertices.ToArray();
        mesh.triangles = triangles.ToArray();
    }
}