Search Unity

  1. Megacity Metro Demo now available. Download now.
    Dismiss Notice
  2. Unity support for visionOS is now available. Learn more in our blog post.
    Dismiss Notice

NullException Error

Discussion in 'Scripting' started by GRiDxkl, Apr 20, 2014.

  1. GRiDxkl

    GRiDxkl

    Joined:
    Apr 20, 2014
    Posts:
    2
    Script:
    var target : Transform;
    var moveSpeed = 3;
    var rotationSpeed = 3;
    var myTransform : Transform;

    function Awake()
    {
    myTransform = transform;
    }

    function Start()
    {
    target = GameObject.FindWithTag("Player").transform;
    }

    function Update(){
    transform.LookAt(Vector3(target.position.x, transform.position.y, target.position.z));

    myTransform.Translate(Vector3.foward * moveSpeed * Time.deltaTime);
    }


    This is my error:
    NullReferenceException: Object reference not set to an instance of an object
    Boo.Lang.Runtime.RuntimeServices.InvokeBinaryOperator (System.String operatorName, System.Object lhs, System.Object rhs)
    AIFollow.Update () (at Assets/AIFollow.js:19)


    What am I failing to assign?
     
  2. frankrs

    frankrs

    Joined:
    Aug 29, 2009
    Posts:
    300
    maybe try

    transform.LookAt(target);
     
  3. BlueFragment27

    BlueFragment27

    Joined:
    Apr 16, 2014
    Posts:
    4
    Have you checked if your object has the tag "Player"?
    If yes, is it active/enabled?

    If no to any of the two questions, GameObject.FindWithTag("Player") will return null. Thus, you get the error when you use target in the Update() function.
     
  4. Dantus

    Dantus

    Joined:
    Oct 21, 2009
    Posts:
    5,667
  5. GRiDxkl

    GRiDxkl

    Joined:
    Apr 20, 2014
    Posts:
    2
    I closed Unity and opened back up and the error was gone...Strange. Thank everyone for their suggestions. Now I know what to look for if problem arises in future.