Help! NullReferenceException: Object reference not set to an instance of an object Example.Update () (at Assets/MOVE.cs:21)

I’m trying to use Unity - Scripting API: CharacterController.Move
But unity says NullReferenceException: Object reference not set to an instance of an object Example.Update () (at Assets/MOVE.cs:21) And I can’t figure it out.

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

public class Example : MonoBehaviour
{
    private CharacterController controller;
    private Vector3 playerVelocity;
    private bool groundedPlayer;
    private float playerSpeed = 2.0f;
    private float jumpHeight = 1.0f;
    private float gravityValue = -9.81f;

    private void Start()
    {
        controller = gameObject.AddComponent<CharacterController>();
    }

    void Update()
    {
        groundedPlayer = controller.isGrounded;
        if (groundedPlayer && playerVelocity.y < 0)
        {
            playerVelocity.y = 0f;
        }

        Vector3 move = new Vector3(Input.GetAxis("Horizontal"), 0, Input.GetAxis("Vertical"));
        controller.Move(move * Time.deltaTime * playerSpeed);

        if (move != Vector3.zero)
        {
            gameObject.transform.forward = move;
        }

        // Makes the player jump
        if (Input.GetButtonDown("Jump") && groundedPlayer)
        {
            playerVelocity.y += Mathf.Sqrt(jumpHeight * -2.0f * gravityValue);
        }

        playerVelocity.y += gravityValue * Time.deltaTime;
        controller.Move(playerVelocity * Time.deltaTime);
    }
}

The answer is always the same… ALWAYS!

How to fix a NullReferenceException error

Three steps to success:

  • Identify what is null ← any other action taken before this step is WASTED TIME
  • Identify why it is null
  • Fix that

NullReference is the single most common error while programming. Fixing it is always the same.

Some notes on how to fix a NullReferenceException error in Unity3D:

http://plbm.com/?p=221

Second note: don’t use the above example code. It is flawed for other reasons.

Here’s two alternatives:

CharacterController CharMover broken:

I wrote about this before: the Unity example code in the API no longer jumps reliably.

If you call .Move() twice in one single frame, the grounded check may fail.

I reported it to Unity via their docs feedback in October 2020. Apparently it is still broken:

Here is a work-around:

I recommend you also go to that same documentation page and ALSO report that the code is broken.

When you report it, you are welcome to link the above workaround. One day the docs might get fixed.

If you would prefer something more full-featured here is a super-basic starter prototype FPS based on Character Controller (BasicFPCC):

That one has run, walk, jump, slide, crouch… it’s crazy-nutty!!

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