How to slow rigidbody?

I'm trying slow my ball down. Sort of like a slow motion ball.

Code (csharp):

1. #pragma strict
2. private var mainGameScript  : MainGame;
3. var particles_splash        : GameObject;
4. var ballSpawn       : GameObject;
5.  
6. function Awake()
7. {
8.     rigidbody.AddForce(0,8,0, ForceMode.Impulse);
9.     InvokeRepeating("IncreaseBallVelocity", 5, 5);
10. }
11.  
12.  
13. function Start()
14. {
15.     mainGameScript = GameObject.Find("GeneralScripts").GetComponent(MainGame);  //Find main game script
16.      Debug.Log(rigidbody.velocity.y);
17. }
18.  
19.  
20. function Update()
21. {
22.     Debug.Log("y" + rigidbody.velocity.y);
23.     Debug.Log("x" + rigidbody.velocity.x);
24.     if(transform.position.x >= 3.658267)
25.     {
26.         Instantiate(ballSpawn, Vector3(-0.03351761, -3, 0), transform.rotation);
27.        
28.         Debug.Log(transform.position.x);
29.         audio.Play();
30.        
31.         if(this.gameObject)
32.         {
33.             Destroy(this.gameObject);
34.         }
35.     }
36.    
37.  
38.    
39.    
40.    
41.     if(transform.position.x <= -3.667952)
42.     {
43.         Instantiate(ballSpawn, Vector3(-0.03351761, -3, 0), transform.rotation);
44.        
45.         Debug.Log(transform.position.x);
46.         audio.Play();
47.        
48.         if(this.gameObject)
49.         {
50.             Destroy(this.gameObject);
51.         }
52.     }
53.    
54.    
55.    
56.     if(transform.position.y >=5.684058 )
57.     {
58.         Instantiate(ballSpawn, Vector3(-0.03351761, -3, 0), transform.rotation);
59.        
60.         Debug.Log(transform.position.x);
61.         audio.Play();
62.        
63.         if(this.gameObject)
64.         {
65.             Destroy(this.gameObject);
66.         }
67.     }
68.    
69.    
70.    
71.     if(transform.position.y <= -8)
72.     {
73.         mainGameScript.SubtractLife();
74.         audio.Play();
75.        
76.         if(this.gameObject)
77.         {
78.             Destroy(this.gameObject);
79.         }
80.     }
81. }
82.  
83.  
84. function IncreaseBallVelocity()
85. {
86.     rigidbody.velocity *= 1.08;
87. }
88.  
89.  
90. function OnCollisionEnter(collision : Collision)
91. {
92.     Instantiate(particles_splash,transform.position, transform.rotation);
93. }
94.    
95.    
96. function OnTriggerEnter(other : Collider)
97. {
98.  
99.  
100.   if(other.gameObject.tag == ("Slow"))
101.   {
102.  
103.         Instantiate(particles_splash,transform.position, transform.rotation);
104.    
105.     Slow();
106.  
107.   }
108.  
109.  }
110.  
111.  function Slow()
112.  
113.  
114.  
115.  {
116.  
117.   rigidbody.AddForce(-100,-100,0, ForceMode.Impulse);
118.  }
119.  
120.  

 

Increasing the drag over time could work, but it will change the flight path.

 

A slow motion effect can be created by slow unity's time down like so:

Code (csharp):

1.     // Toggles the time scale between 1 and 0.7
2.     // whenever the user hits the Fire1 button.
3.     function Update () {
4.         if (Input.GetButtonDown ("Fire1")) {
5.             if (Time.timeScale == 1.0)
6.                 Time.timeScale = 0.7;
7.             else
8.                 Time.timeScale = 1.0;
9.             // Adjust fixed delta time according to timescale
10.             // The fixed delta time will now be 0.02 frames per real-time second
11.             Time.fixedDeltaTime = 0.02 * Time.timeScale;
12.         }
13.     }

Source: http://docs.unity3d.com/Documentation/ScriptReference/Time-timeScale.html

This however will slow ALL rigidbodies in the scene, so probably not ideal if you only want one body to slow.

 

you can also multiply the velocity by 0.99f (or more..err less?), which is similar to drag.

Depends on what kind of effect you are trying to achieve (slow motion, or slow down)

 

You should never directly modify the value of the velocity, in a physics system this can lead to unintended behaviour.
A more realistic approach is to apply change from a 'physics' perspective, i.e increase the drag, or create an opposing force on the rigidbody to slow it down.

 

thanks all i went with drag, waited a few seconds, then changed the speed back to normal.

 

Are you sure about that? While I agree that moving a rigidbody by modifying the velocity directly should be the option of last resort because it can lead to things going haywire, I wouldn't say that it should never be done. I have done it on a couple of occasions before without any issues.

 

Well you should never, but you still can. I would call it more of a 'best practice' scenario.
You should never build up your SQL statements with strings and variables without parameterising them, but you still can.. and you will usually get away it it.

 

There is no need to modify the velocity directly. You can just find out the velocity vector v = rigidnbody.velocity. Then apply rigidbody.addforce(-v/v.magnitude * (v-v0).magnitude * dragCoefficient, ForceMode.Force). Drag is essentially a velocity-dependent force, so if you apply that code in FixedUpdate it should slow down the rigidbody to velocity v0.

 

I think that comparing the security risk of string concatenation in SQL statement to possible physics glitches is mixing explosive apples with bouncy oranges .

That's a great looking game in your signature by the way.

 

A good way would be to apply a force to the ball in th direction of the surface it is on, kinda like brakes in a car.

Something like this:

Code (csharp):

1. rigidbody.AddForce(Vector3.down * 10)

 

There are situations where modifying the velocity directly is the best solution.

Even Unity's jump example does it. http://docs.unity3d.com/Documentation/ScriptReference/Rigidbody-velocity.html

I generally use opposite forces, but I really cbf explaining how to do that here.

 

My ball keeps getting stuck going left to right. Is there a way where the ball will always go somewhere new instead of staying with point a and point b. it starts off fine but sometimes does this. Ball is bouncing on bricks like brick breaker on x and y axis.