Unity Cheat Sheet and Quick Reference 2018

Jeff Fisher

Unity Cheat Sheet and Quick Reference Now Available!

Unity Cheat Sheet and Quick Reference Now Available!

When working on Unity projects, I often find myself asking the same questions over and over.

When should I use FixedUpdate() over Update()?

What’s the process of kicking off a coroutine again?

Why are my 2D collisions not working?

What are some of the static Vector3 variables available to me?

These simple questions can be answered by a quick Google search, but the process of answering them can break the flow of a work session. Once a flow has been broken, it can be a non-trivial affair to get back into it.

So I put together a Cheat Sheet to keep the flow alive, and you can download it here:

The sheet summarizes some of the more commonly used features in Unity using C#. Here’s what’s included!

MonoBehaviour Event Execution Order

Ordered by first to last method to execute.

private void Awake() { /* Called when the script is being loaded */ }
private void OnEnable() { /* Called every time the object is enabled */ }
private void Start() { /* Called on the frame when the script is enabled */ }
private void Update() { /* Called once per frame */ }
private void LateUpdate() { /* Called every frame after Update */ }
private void OnBecameVisible() { /* Called when the renderer is visible by any Camera */ }
private void OnBecameInvisible() { /* Called when the renderer is no longer visible by any Camera */ }
private void OnDrawGizmos() { /* Allows you to draw Gizmos in the Scene View */ }
private void OnGUI() { /* Called multiple times per frame in response to GUI events */ }
private void OnApplicationPause() { /* Called at the end of a frame when a pause is detected */ }
private void OnDisable() { /* Called every time the object is disabled */ }
private void OnDestroy() { /* Only called on previously active GameObjects that have been destroyed */ }

Physics updates on a Fixed Timestep are defined under Edit ▸ Project Settings ▸ Time ▸ Fixed Timestep and may execute more or less than once per actual frame.

private void FixedUpdate() { /* Called every Fixed Timestep */ }

See the Physics Events section for a quick reference on associated Physics methods.

GameObject Manipulation

/* Create a GameObject */
Instantiate(GameObject prefab);
Instantiate(GameObject prefab, Transform parent);
Instantiate(GameObject prefab, Vector3 position, Quaternion rotation);
/* In Practice */
Instantiate(bullet);
Instantiate(bullet, bulletSpawn.transform);
Instantiate(bullet, Vector3.zero, Quaternion.identity);
Instantiate(bullet, new Vector3(0, 0, 10), bullet.transform.rotation);

/* Destroy a GameObject */
Destroy(gameObject);

/* Finding GameObjects */
GameObject myObj = GameObject.Find("NAME IN HIERARCHY");
GameObject myObj = GameObject.FindWithTag("TAG");

/* Accessing Components */
Example myComponent = GetComponent<Example>();
AudioSource audioSource = GetComponent<AudioSource>();
Rigidbody rgbd = GetComponent<Rigidbody>();

Vector Quick Reference

X = Left/Right   Y = Up/Down   Z = Forward/Back

Vector3.right /* (1, 0, 0) */   Vector2.right /* (1, 0) */
Vector3.left /* (-1, 0, 0) */   Vector2.left /* (-1, 0) */
Vector3.up /* (0, 1, 0) */      Vector2.up /* (0, 1) */
Vector3.down /* (0, -1, 0) */   Vector2.down /* (0, -1) */
Vector3.forward /* (0, 0, 1) */
Vector3.back /* (0, 0, -1) */
Vector3.zero /* (0, 0, 0) */    Vector2.zero /* (0, 0) */
Vector3.one /* (1, 1, 1) */     Vector2.one /* (1, 1) */
float length = myVector.magnitude /* Length of this Vector */
myVector.normalized /* Keeps direction, but reduces length to 1 */

Time Variables

/* The time in seconds since the start of the game */
float timeSinceStartOfGame = Time.time;

/* The scale at which the time is passing */
float currentTimeScale = Time.timeScale;
/* Pause time */
Time.timeScale = 0;

/* The time in seconds it took to complete the last frame */
/* Use with Update() and LateUpdate() */
float timePassedSinceLastFrame = Time.deltaTime;

/* The interval in seconds at which physics and fixed frame rate updates are performed */
/* Use with FixedUpdate() */
float physicsInterval =  Time.fixedDeltaTime;

Physics Events

/* Both objects have to have a Collider and one object has to have a Rigidbody for these Events to work */
private void OnCollisionEnter(Collision hit) { Debug.Log(gameObject.name + " just hit " + hit.gameObject.name); }
private void OnCollisionStay(Collision hit) { Debug.Log(gameObject.name + " is hitting " + hit.gameObject.name); }
private void OnCollisionExit(Collision hit) { Debug.Log(gameObject.name + " stopped hitting " + hit.gameObject.name); }

/* Trigger must be checked on one of the Colliders */
private void OnTriggerEnter(Collider hit) { Debug.Log(gameObject.name + " just hit " + hit.name); }
private void OnTriggerStay(Collider hit) { Debug.Log(gameObject.name + " is hitting " + hit.name); }
private void OnTriggerExit(Collider hit) { Debug.Log(gameObject.name + " stopped hitting " + hit.name); }
 
/* For 2D Colliders just add 2D to the Method name and the Parameter Type */
private void OnCollisionEnter2D(Collision2D hit) { }
private void OnCollisionStay2D(Collision2D hit) { }
private void OnCollisionExit2D(Collision2D hit) { }
private void OnTriggerEnter2D(Collider2D hit) { }
private void OnTriggerStay2D(Collider2D hit) { }
private void OnTriggerExit2D(Collider2D hit) { }

Coroutines

/* Create a Coroutine */
private IEnumerator CountSeconds(int count = 10)
{
  for (int i = 0; i <= count; i++) {
    Debug.Log(i + " second(s) have passed");
    yield return new WaitForSeconds(1.0f);
  }
}

/* Call a Coroutine */
StartCoroutine(CountSeconds());
StartCoroutine(CountSeconds(10));

/* Call a Coroutine that may need to be stopped */
StartCoroutine("CountSeconds");
StartCoroutine("CountSeconds", 10);

/* Stop a Coroutine */
StopCoroutine("CountSeconds");
StopAllCoroutines();

/* Store and call a Coroutine from a variable */
private IEnumerator countSecondsCoroutine;

countSecondsCoroutine = CountSeconds();
StartCoroutine(countSecondsCoroutine);

/* Stop a stored Coroutine */
StopCoroutine(countSecondsCoroutine);

/* Coroutine Return Types */
yield return null; // Waits until the next Update() call
yield return new WaitForFixedUpdate(); // Waits until the next FixedUpdate() call
yield return new WaitForEndOfFrame(); // Waits until everything this frame has executed
yield return new WaitForSeconds(float seconds); // Waits for game time in seconds
yield return new WaitUntil(() => MY_CONDITION); // Waits until a custom condition is met
yield return new WWW("MY/WEB/REQUEST"); // Waits for a web request
yield return StartCoroutine("MY_COROUTINE"); // Waits until another Coroutine is completed

Input Quick Reference

if (Input.GetKeyDown(KeyCode.Space)) { Debug.Log("Space key was Pressed"); }
if (Input.GetKeyUp(KeyCode.W)) { Debug.Log("W key was Released"); }
if (Input.GetKey(KeyCode.UpArrow)) { Debug.Log("Up Arrow key is being held down"); }

/* Button Input located under Edit >> Project Settings >> Input */
if (Input.GetButtonDown("ButtonName")) { Debug.Log("Button was pressed"); }
if (Input.GetButtonUp("ButtonName")) { Debug.Log("Button was released"); }
if (Input.GetButton("ButtonName")) { Debug.Log("Button is being held down"); }

Hotkeys

Where to Go From Here?

Looking to learn Unity? Feel free to watch our Unity video tutorial series or read our written Unity tutorials.

If you have any suggestions on how to improve this Cheat Sheet, please let me know in the comments!

Team

Each tutorial at www.raywenderlich.com is created by a team of dedicated developers so that it meets our high quality standards. The team members who worked on this tutorial are:

Jeff Fisher

Jeff is an indie game developer and co-founder at Luna Wolf Studios. He’s certified in Unity development, and has a degree in Game Design and Development from Wilmington University. Jeff has published numerous games for various platforms, and has worked with a variety of clients. When he’s not making games, he’s most likely talking about them.

Other Items of Interest

Save time.
Learn more with our video courses.

raywenderlich.com Weekly

Sign up to receive the latest tutorials from raywenderlich.com each week, and receive a free epic-length tutorial as a bonus!

Advertise with Us!

PragmaConf 2016 Come check out Alt U

Our Books

Our Team

Video Team

... 27 total!

iOS Team

... 83 total!

Android Team

... 44 total!

Unity Team

... 16 total!

Articles Team

... 4 total!

Resident Authors Team

... 31 total!

Podcast Team

... 7 total!

Recruitment Team

... 8 total!

Illustration Team

... 4 total!