• Products
  • Solutions
  • Made with Unity
  • Learning
  • Support & Services
  • Community
  • Asset Store
  • Get Unity

UNITY ACCOUNT

You need a Unity Account to shop in the Online and Asset Stores, participate in the Unity Community and manage your license portfolio. Login Create account
  • Blog
  • Forums
  • Answers
  • Evangelists
  • User Groups
  • Beta Program
  • Advisory Panel

Navigation

  • Home
  • Products
  • Solutions
  • Made with Unity
  • Learning
  • Support & Services
  • Community
    • Blog
    • Forums
    • Answers
    • Evangelists
    • User Groups
    • Beta Program
    • Advisory Panel

Unity account

You need a Unity Account to shop in the Online and Asset Stores, participate in the Unity Community and manage your license portfolio. Login Create account

Language

  • Chinese
  • Spanish
  • Japanese
  • Korean
  • Portuguese
  • Ask a question
  • Spaces
    • Default
    • Help Room
    • META
    • Moderators
    • Topics
    • Questions
    • Users
    • Badges
  • Home /
avatar image
0
Question by DAVco · May 27, 2013 at 11:57 AM · physicsframeratefixedupdateindependent

Framerate independent physics (FixedTimestep, FixedDeltaTime)

How do I achieve 'correct' framerate-independent physics in Unity?

As I understand it; physics logic should always be performed in the FixedUpdate() function (Application of forces, etc), but does this mean I should scale my forces by Time.fixedDeltaTime - similarly to the way we should scale by the [variable] deltaTime in the Update() function for game logic - or is this taken care of by the physics engine its-self?

My reasoning for this is; if the number of required physics steps or the fixed update duration changes, then the forces applied will no longer be correct. However if the physics engine already takes this into account, then there is no reason to do the multiplication myself.

I've read a few articles on the topic of physics in Unity, however there seems to be a lot of confusion and misinformation out there regarding how to properly achieve framerate-independence - perhaps this thread can clear some of that up? :)

Comment
Add comment
10 |3000 characters needed characters left characters exceeded
▼
  • Viewable by all users
  • Viewable by moderators
  • Viewable by moderators and the original poster
  • Advanced visibility
Viewable by all users

1 Reply

· Add your reply
  • Sort: 
avatar image
0
Best Answer

Answer by Broheim · May 27, 2013 at 12:58 PM

i think it's not that complicated at all. Use Time.deltaTime in your FixedUpdate, it will return the fixedDeltaTime when used within FixedUpdate. It's some kind of Unity shortcut. You do need to use deltaTime to make your game frame-independent.

Comment
Add comment · Show 1 · Share
10 |3000 characters needed characters left characters exceeded
▼
  • Viewable by all users
  • Viewable by moderators
  • Viewable by moderators and the original poster
  • Advanced visibility
Viewable by all users
avatar image DAVco · May 27, 2013 at 01:15 PM 0
Share

I did notice that the docs say that Time.deltaTime returns the fixed update delta if used from within the fixed function. However the documentation doesn't appear to actually use this anywhere.

Your answer

Hint: You can notify a user about this post by typing @username

Up to 2 attachments (including images) can be used with a maximum of 524.3 kB each and 1.0 MB total.

Welcome to Unity Answers

If you’re new to Unity Answers, please check our User Guide to help you navigate through our website and refer to our FAQ for more information.

Before posting, make sure to check out our Knowledge Base for commonly asked Unity questions.

Check our Moderator Guidelines if you’re a new moderator and want to work together in an effort to improve Unity Answers and support our users.

Follow this Question

Answers Answers and Comments

15 People are following this question.

avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image avatar image

Related Questions

FixedUpdate and Time.deltaTime slowe 2 Answers

Unity Physics frame rate. void FixedUpdate 3 Answers

How to smooth physics without interpolation 0 Answers

Physics behaviour changing with framerate - Is FixedUpdate() actually working properly? 3 Answers

Game not running properly on slow machines (low fps) 1 Answer


Enterprise
Social Q&A

Social
Subscribe on YouTube social-youtube Follow on LinkedIn social-linkedin Follow on Twitter social-twitter Follow on Facebook social-facebook Follow on Instagram social-instagram

Footer

  • Purchase
    • Products
    • Subscription
    • Asset Store
    • Unity Gear
    • Resellers
  • Education
    • Students
    • Educators
    • Certification
    • Learn
    • Center of Excellence
  • Download
    • Unity
    • Beta Program
  • Unity Labs
    • Labs
    • Publications
  • Resources
    • Learn platform
    • Community
    • Documentation
    • Unity QA
    • FAQ
    • Services Status
    • Connect
  • About Unity
    • About Us
    • Blog
    • Events
    • Careers
    • Contact
    • Press
    • Partners
    • Affiliates
    • Security
Copyright © 2020 Unity Technologies
  • Legal
  • Privacy Policy
  • Cookies
  • Do Not Sell My Personal Information
  • Cookies Settings
"Unity", Unity logos, and other Unity trademarks are trademarks or registered trademarks of Unity Technologies or its affiliates in the U.S. and elsewhere (more info here). Other names or brands are trademarks of their respective owners.
  • Anonymous
  • Sign in
  • Create
  • Ask a question
  • Spaces
  • Default
  • Help Room
  • META
  • Moderators
  • Explore
  • Topics
  • Questions
  • Users
  • Badges