Vector3.Normolize
Vector3.magnitude
Vector3.sqrMagnitude
Vector3.Slerp  

using UnityEngine;
using System.Collections;

     public class Controller  : MonoBehaviour
     {

         public GameObject PointCam;
         public GameObject Player;

         Ray ray;
         RaycastHit hit;
         Vector3 pos = new Vector3();

         void Update()
         {
             if (Input.GetMouseButtonDown(0))
             {
                 ray = UnityEngine.Camera.main.ScreenPointToRay(Input.mousePosition);
                 if (Physics.Raycast(ray, out hit, 1000000f))
                 {
                     Instantiate(PointCam, hit.point, Quaternion.identity);
                 }
                  
             }
         }
        
     }// end

NullReferenceException: Object reference not set to an instance of an object
Controller.Update () (at Assets/Script/Controller.cs:22)