What is the difference between Update() , LateUpdate() , FixedUpdate(), and when i should use them

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Update() , LateUpdate() and FixedUpdate()

what is the difference between these and when i should use one of them and is it wrong to use Update() all the time?

Answer 1

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Answer by Meltdown · Aug 05, 2011 at 05:10 AM

Check out this link on Update Order

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Ziad · Aug 05, 2011 at 05:16 AM 0

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this is a good answer :D

Ziad · Aug 05, 2011 at 05:18 AM 0

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but.... can i have example about when i should use one of them :)

Meltdown · Aug 05, 2011 at 05:30 AM 2

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Generally, you will use Update for most operations. Such as changing transforms, or rotating items. FixedUpdate is usually used when you are calculating physics, such as applying forces to a rigidbody. i.e rigidbody.AddForce() etc. Anything that does calculations on the physcs side of things is usually used in FixedUpdate. In most other cases you will use Update().

Ziad · Aug 05, 2011 at 06:02 AM 0

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realy thanks dude :)

aldonaletto · Sep 30, 2012 at 08:25 PM 1

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I suppose this page was replaced by this one: http://docs.unity3d.com/Documentation/$$anonymous$$anual/ExecutionOrder.html

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Answer 2

Answer by GizmoKaracho · Aug 30, 2017 at 10:13 AM

Update() is called on every Frame, regardless of time passed since last frame
- Good for Movement, InputControl etc. (most of the time you'll use Update)
- Usually you will use Time.DeltaTime to take passed time into account (e.g. for GameObject Translations)
LateUpdate() is called after all Update() methods are processed
- So e.g. for the camera that follows your character it's good to Update after it has moved
FixedUpdate() is called by the physics engine in fixed intervals (that can be set in the Options)
- This is basically good for all Physics related functions (trigger, collisions etc.)

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Answer 3

Answer by mdforbes500 · Aug 11, 2017 at 06:48 AM

Don't forget, @Ziad , that if you are performing camera scripting its best to put it in LateUpdate(). That way the movement calculations have already been done.

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jessejarvis · Aug 30, 2017 at 12:21 AM 0

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I have in a LateUpdate function:

 if(!thisVariable)
      thisVariable = GetComponent<Component>();

Originally I had it in a Start() function but sometimes it wasn't setting itself which is why I set it here.

Is that okay for performance?

aldonaletto jessejarvis · Sep 02, 2017 at 01:44 AM 0

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Since thisVariable is initialized only once (that's the so-called "lazy initialization"), the impact on the performance is negligible - just an if instruction that evaluates false every frame but the first one.

What is the difference between Update() , LateUpdate() , FixedUpdate(), and when i should use them

Update() , LateUpdate() and FixedUpdate()

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