How do I add force in the on trigger

Question

Hi, I have this simple problem, I have an object and a group of objects (prefab) named coin. All I have to do is addforce to the coins when they enter the main object. The collision/trigger thingy works, when I change the "coin.rigidbody.AddRelativeForce (0, power, 0);" line, it works so the problem is with that line.

 var coin : GameObject;
 static var speed : int;
 var power;
 
 
 
 function Start () {
 InvokeRepeating("checking", 0, 0.3);
 }
 
 function OnTriggerEnter ( collision : Collider){
 
  
  coin.rigidbody.AddRelativeForce (0, power, 0);
 
 }
 
 function checking (){
 power = speed/3;
 
 
 }

(the var power is set in other script

Answer 1

Best Answer

Answer by alucardj · Mar 22, 2013 at 02:29 PM

The problem is you want to add an instantaneous force, where AddForce is applied over time in physics. For an instantaneous force in your case of entering a trigger volume, you need to use ForceMode.Impulse :

 rigidbody.AddForce( transform.up * power, ForceMode.Impulse );

Links :

http://docs.unity3d.com/Documentation/ScriptReference/Rigidbody.AddForce.html

http://docs.unity3d.com/Documentation/ScriptReference/ForceMode.Impulse.html

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RGI · Mar 22, 2013 at 02:40 PM 0

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there is just one slight error, it moves the main object instead of the coins :D. How do I swap them?

Polinator · Mar 22, 2013 at 02:44 PM 0

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use coin.rigidbody.AddForce( transform.up * power, ForceMode.Impulse );

alucardj · Mar 22, 2013 at 02:46 PM 1

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well that was just an example. I see you want to affect the coin? :

 coin.rigidbody.AddForce( transform.up * power, ForceMode.Impulse );

or

 coin.rigidbody.AddRelativeForce( Vector3.up * power, ForceMode.Impulse );

or

 coin.rigidbody.AddRelativeForce( 0, power, 0, ForceMode.Impulse );

Please read the code and see what it is doing.

 // coin : the cached gameObject
 // rigidbody : the component on that gameObject
 // AddForce and AddRelativeForce : check the Unity Scripting Reference
 // transform.up : the up vector in relation to the transform
 // * power : the modifier of the vector
 // ForceMode.Impulse : This Is The Important Part, as detailed in my answer

RGI · Mar 22, 2013 at 03:07 PM 0

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okay, it is working when I set the coin var to a certain object already in game. Problem is, The coins are spawed randomly with a script, so when they are spawned, they dont react with the main object. I forgot to mention that, sry. And another thing is that Iam planning on adding more stuff doing pretty much the same as coins so, I would need the script to activate on trigger with ANY object. Not just coins. Thank you, btw.

Polinator · Mar 22, 2013 at 09:08 PM 0

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Read the documentation on gameObject.tags. All of your issues you have described above will be solved when you learn that.

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How do I add force in the on trigger

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