title: Unity C# UnassignedReferenceException
body: <p>When i run </p>
  
  <pre class="lang-cs prettyprint-override"><code>using UnityEngine;
  
  public class PlayerMovment : MonoBehaviour
  {
      public Rigidbody rb;
  
      void Start()
      {
          rb.useGravity = false;
      }
  
      void Update()
      {
  
      }
  }
  </code></pre>
  
  <p>it gives me<br></p>
  
  <pre>
  UnassignedReferenceException: The variable rb of PlayerMovment has not been assigned.
  You probably need to assign the rb variable of the PlayerMovment script in the inspector.
  PlayerMovment.Start ()
  </pre>
  
  <p>I rewrote the script couple of times but it gives the the same error. How can i fix it? </p>