• 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 /
  • Help Room /
This question was closed Aug 09, 2018 at 08:33 PM by MT369MT for the following reason:

The question is answered, right answer was accepted

avatar image
0
Question by kIsForKid · Aug 09, 2018 at 05:13 PM · newbieunity 4movetowardsvectors

Why does this vector multiplication change its direction?

Hi, I'm using Unity 4 and spawning an object in the same position every second. Each time an object is spawned, a vector is drawn from the object to moveTowardsPos (the position of my player-character). I use the code in the Start() method to mark where I want my vector to be drawn to and the code in the Update() method to draw two vectors.

     void Start () {
     
         player = GameObject.FindObjectOfType<Player>();
     
         moveTowardsPos = player.transform.position;
         
         Vector2 direction = player.transform.position - transform.position;
         float angle = Mathf.Atan2(direction.y,direction.x) * Mathf.Rad2Deg + 270;
         Quaternion rotation = Quaternion.AngleAxis(angle, Vector3.forward);
         transform.rotation = Quaternion.Slerp(transform.rotation, rotation, 100.00f * Time.deltaTime);
     }
 void Update () {
     
         Debug.Log (moveTowardsPos);
         
         Debug.DrawLine(this.gameObject.transform.position, moveTowardsPos, Color.green);
         Debug.DrawLine(this.gameObject.transform.position, moveTowardsPos * 2.0f, Color.red);
 
     }

I'm drawing a green vector that starts at my object and ends at moveTowardsPos (the position of my player-character). I want the red vector to be in the same direction as the green vector, but just twice as long.

However, this is what happens when I play the game: https://i.imgur.com/z8S7IgN.png

The red vector is longer than the green, but they are not in the same direction. A vector multiplied by 2 should just be a vector twice as long in the same direction, no?

Is there something I don't understand about how vectors work in Unity? How can I have the red vector be in the same direction but just be twice as long?

Thanks in advance :)

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

  • Sort: 
avatar image
1
Best Answer

Answer by MT369MT · Aug 09, 2018 at 08:19 PM

Hi, to draw a line you must enter the start and the end of the line NOT the direction. So it will not duplicate the direction but the end point vector. To solve this, simply subtract the transform.position like this:

 Debug.DrawLine(this.gameObject.transform.position, moveTowardsPos, Color.green);
 Debug.DrawLine(this.gameObject.transform.position, moveTowardsPos * 2.0f - transform.position, Color.red);
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 kIsForKid · Aug 11, 2018 at 09:58 PM 0
Share

Hi, sorry if this is a bit late, but thank you for your help! This code worked well for what I wanted.

I didn't quite understand how this worked, so I drew out the vectors on graph paper and the math was solid. Thanks! :)

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

150 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 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 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 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 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 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 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 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 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 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

How can I translate my game object from a certain coordinate to the negative values of the same coordinate? 1 Answer

What is the best way to find direction between two objects? 0 Answers

GetComponent returns null 1 Answer

how do i make my character float down? 0 Answers

Collider CS0131 issue 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