Problem with spawn custom mesh on prefab terrain

Hello Guys,

I'm learning Unity and C#. I have created own mesh in shape of pyramid and made prefab from it. I want to spawn those meshes on the ground surface, however have found it difficult as it seams that transform.position is somehow broken for my mesh or I'm doing something wrong.

When tried to place meshes without using transform.position meshes spawned Perfectly on ground, however on the Inspector coordinates had value 0 (which couldn't be position of my mesh). When I try to place my pyramids basing on raycast hist, objects are spawn high above the ground (picture) instead on it. I've also made simple prefab from 3D Cube and then wanted to see if same problem occur. However Cubes spawns perfectly (second picture).

So could give me some solutions what am I doing wrong? I would appreciate any help as I'm stuck for almost week.

Below I attach also codes for generating pyramid and spawn objects:

BOID:

 using System;
 using UnityEngine;
 using UnityEngine.AI;
 using Random = UnityEngine.Random;
 
 public class Boid : MonoBehaviour
 {
 
     private Vector3 _position;
     private Color _selectedColor = Color.white;
     private NavMeshAgent _agent;
     
 
     public void Start()
     {
         _position = gameObject.transform.position;
         MeshFilter meshFilter = GetComponent<MeshFilter>();
         if (meshFilter == null)
         {
             Debug.LogError("MeshFilter not found!");
             return;
         }
         MeshCollider meshCollider = gameObject.GetComponent<MeshCollider>();
         if (meshCollider == null)
         {
             Debug.LogError("MeshCollider not found!");
             return;
         }
 
         MeshRenderer meshRenderer = gameObject.GetComponent<MeshRenderer>();
         if (meshRenderer == null)
         {
             Debug.LogError("MeshRenderer not found!");
             return;
         }
         
         float X = _position.x;
         float Y = _position.y;
         float Z = _position.z;
         
         Vector3 p0 = new Vector3(X, Y + 1, Z);
         Vector3 p1 = new Vector3(X + 1,Y + 1, Z);
         Vector3 p2 = new Vector3(X + 1,Y, Z);
         Vector3 p3 = new Vector3(X, Y, Z);
         Vector3 p4 = new Vector3((X + X +1) / 2, (Y + Y + 1) / 2, Z + 1);
        
         Mesh mesh = new Mesh();
         
         mesh.vertices = new Vector3[]{
             p1,p2,p0,
             p2,p3,p0,
             p4,p1,p0,
             p4,p2,p1,
             p4,p3,p2,
             p4,p0,p3
         };
         mesh.triangles = new int[]{
             0,1,2,
             3,4,5,
             6,7,8,
             9,10,11,
             12,13,14,
             15,16,17
         };
         Vector2 uv0  = new Vector2(0.25f,0.25f);
         Vector2 uv3  = new Vector2(0.25f,0.75f);
         Vector2 uv1 = new Vector2(0.75f, 0.25f);
         Vector2 uv2 = new Vector2(0.75f, 0.75f);
         Vector2 uv4a = new Vector2(0,0.5f);
         Vector2 uv4b = new Vector2(0.5f, 1);
         Vector2 uv4c = new Vector2(1, 0.5f);
         Vector2 uv4d = new Vector2(0.5f, 0);
 
         mesh.uv = new Vector2[]{
             uv0,uv1,uv3,
             uv1,uv2,uv3,
             uv0,uv1,uv4d,
             uv1,uv2,uv4c,
             uv2,uv3,uv4b,
             uv3,uv0, uv4a
         };
         meshRenderer.material = Resources.Load("BasicMaterial") as  Material;
         meshRenderer.material.color = _selectedColor;
         // meshRenderer.materials = materials.ToArray();
         mesh.RecalculateNormals();
         mesh.RecalculateBounds();
         mesh.Optimize();
         
         meshCollider.sharedMesh = mesh;
         meshFilter.sharedMesh = mesh;
     }
 
     public void SetSelectedVisible(bool visible)
     {
         if (visible)
         {
             _selectedColor = Color.red;
         }
         else
         {
             _selectedColor = Color.white;
         }
         gameObject.GetComponent<MeshRenderer>().material.color = _selectedColor;
     }
 
     public void MoveTo(Vector3 position)
     {
         _agent.SetDestination(position);
         
     }
 }
 

SPAWING:

 using System;
 using TMPro;
 using UnityEngine;
 using UnityEngine.AI;
 using Button = UnityEngine.UI.Button;
 
 public class SpawnObjects : MonoBehaviour
 {
     public Button buttonClick;
     public TMP_InputField spawnNumber;
 
     private readonly Vector3 _initCameraPosition = new (0.0f, 100.0f, 0.0f);
     private GameObject _spawnTerrain;
 
     private float maxHeight = 100.0f;
     private RaycastHit _raycastHit;
     private int _currentObjectNumber;
     private int _columnNumber;
     private void Start()
     {
         _spawnTerrain = GameObject.FindGameObjectWithTag("Respawn");
         Debug.Log(_spawnTerrain);
         
         buttonClick.onClick.AddListener(Spawn);
     }
     public void Spawn()
     {
         int numberOfSpawnObject = int.Parse(spawnNumber.text);
         int objectsInRowNumber = getNumberOfObjectInRow(numberOfSpawnObject);
         for (int i = 0; i < numberOfSpawnObject; i++)
         {
             if (_currentObjectNumber == objectsInRowNumber)
             {
                 _currentObjectNumber = 0;
                 _columnNumber += 1;
             }
             
             float x = _initCameraPosition.x + 2 * _currentObjectNumber;
             float y = _initCameraPosition.y;
             float z = _initCameraPosition.z  + 2 * _columnNumber;
 
             Vector3 init = new Vector3(x, y, z);
             Vector3 spawnPosition = Vector3.zero;
             
             
             if (Physics.Raycast(init, Vector3.down, out _raycastHit))
             {
                 Debug.Log("HIT:" + _raycastHit.point);
                 spawnPosition = _raycastHit.point;
                 Debug.DrawRay(spawnPosition, Vector3.down, Color.blue, 10.0f);
             }
 
             GameObject boid = Resources.Load("Block") as GameObject;
             boid.transform.position = spawnPosition;
             Instantiate(boid);
             _currentObjectNumber += 1;
         }
     }
 
     private int getNumberOfObjectInRow(int objectNumber)
     {
         return (int) Math.Sqrt(objectNumber);
     }
 }
 

[1]: /storage/temp/195371-boids.png