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Game Development How to Make a Video Game Pickups Script the Fly Movement

Posted by Andrew Molloy
Andrew Molloy
37,259 Points

Why FixedUpdate for Animation?

Nick Pettit, I think I have to disagree with the reasoning for using FixedUpdate here. By multiplying by Time.deltaTime you're already making it a constant update no matter the frame rate and so the fly RotateAround should be placed in Update rather than FixedUpdate. FixedUpdate really should only be used for physics engine related/reliant updates. The only real difference is on a system where the frame rate is very fast you're not going to take advantage of that because you'll be missing frames to update a render by putting the change in rotation in the constant frame rate of FixedUpdate(), and on a very slow frame rate system you're wasting calculations that won't be rendered.

But it's late in the day so I may be missing something. :) Great intro course otherwise for beginners (I've gone through a few over the years for Unity), very practical.

2 Answers

Nick Pettit
STAFF
Nick Pettit
Treehouse Teacher
Nick Pettit
Nick Pettit
Treehouse Teacher

I'm pretty sure you're correct! Originally I had some code there that used a rigidbody and I needed FixedUpdate() and now I can't figure out why I still used FixedUpdate... Whoops. :P

I'll have this corrected soon!

Nick Pettit
Nick Pettit
Treehouse Teacher
Nick Pettit
Nick Pettit
Treehouse Teacher

Just FYI: Time.deltaTime will read the same if you're in Update() or FixedUpdate()

See here: http://docs.unity3d.com/ScriptReference/Time-fixedDeltaTime.html

Alan Mattanó
PLUS
Alan Mattanó
Courses Plus Student 12,188 Points
Alan Mattanó
Alan Mattanó
Courses Plus Student 12,188 Points

If you make the game physics at 0.03(33fps) of a second of FixedUpdate and then you change to a FixedUpdate of 0.01 (100fps) the animation will run faster. Multiplying by Time.deltaTime give you the ability to prevent certain problems and maintain the speed of the animation if the physics time step is change later in your project.

Andrew Molloy
Andrew Molloy
37,259 Points

Unless you used Time.fixedDeltaTime which would account for that, but then that's only if it's really necessary to have inside FixedUpdate.