CastSphereALL Help please

Unity Engine
1

I’m trying to make an explosion, that damages all the units around it.

I’m new to unity but have done this with other programs before.

So far I’ve got

RaycastHit[ ] hit = Physics.SphereCastAll(transform.position, 30.0f, transform.up, 0.00f);

foreach(RaycastHit q in hit){
print (q.collider.gameObject.tag);
}

I’m struggling to understand what parameters unity wants, surely the third should be PI, but it wants a vector, even tho PI would make sense.

I also don’t want the Sphere to move, I just want to cast a 30m sphere around the objects position and detect all objects in the radius.

2

Any ideas?

3

I would do something as following:

  1. create a prefab called ExplosionPrefab
  2. create a script called Grenade
  3. create a prefab called GrenadePrefab
  4. attach the Grenade script to the GrenadePrefab
  5. create a script call Throw
  6. attach the Throw script to the MainCamera of a character controller

In your scripts:

//ThrowScript.js which is attached to the MainCamera
var explosionPower: float = 2000.0;
var grenadePrefab : Transform;

function Update () 
{
	//left mouse button is pressed
	if (Input.GetButtonDown("Fire1"))
	{
		//create grenade prefab
		var grenade = Instantiate(grenadePrefab, transform.position, Quaternion.identity);
		
		//throw the grenade by adding the forward force
		grenade.rigidbody.AddForce(transform.forward * explosionPower);
	
	}
}

Grenade script which is attached to the GrenadePrefab

//GrenadeScript.js
var explosionTime: float = 2.0;
var explosionRadius: float = 5.0;
var explosionDistane: float = 10.0;
var explosionPower: float = 2000.0;
var explosionPrefab: Transform;

function Awake()
{
	explosionTime = Time.time;
}

function Update()
{
    //delay grenade explosion
	if (Time.time > explosionTime + 2)
	{
	    //create the explosion
		Instantiate(explosionPrefab, transform.position, Quaternion.identity);
	
	    //find all nearby colliders
		//use the statement below
           //var colliders : Collider[] = Physics.OverlapSphere(transform.position, explosionRadius);
		//or use the statement below
		var hit: RaycastHit[] = Physics.SphereCastAll(transform.position, explosionRadius, transform.up, explosionDistane);
		
	    //apply a force to all surrounding rigid bodies
	    for( var hitObject in hit)
	    {
		   //check to make sure to apply force to only a game object that has rigid body component
		   if (hitObject.rigidbody)
		   {
			   hitObject.rigidbody.AddExplosionForce(explosionPower, transform.position, explosionRadius);
		   }
	    }
		
	    Destroy(gameObject);
	}

}

Make sure that you assign grenadePrefab and explosionPrefab in the property Inspector.

4

Thank you, but I don’t understand the function, why is there explosion distance and explosion radius, whats the point in distance if you have radius?

5

Well, I do not understand all the details of the SphereCastAll function. However, according to the Unity document:

ExplosionRadius (Radius) is the radius of the sphere.
ExplosionDistance (Distance) is th length of the sweep.

The sweep (Distance) starts from a center of a sphere; therefore, technically you can set Radius to zero and Distance to 10 unit and it still does the same thing.

6

Sorry to revive an old thread but in case it’s helpful to other developers, I believe the ‘Cast’ functions will not return objects that collide with the collider function in its initial position (overlap).
For example, for SphereCastAll, the initial space occupied by the sphere is ignored - only collisions that occur while the sphere is traveling (cast) will be taken into account.

7

As you said there are a lot of weird parameters there, that´s because that isn´t the function you´re looking for.

Check the Physics.OverlapSphere instead. http://docs.unity3d.com/Documentation/ScriptReference/Physics.OverlapSphere.html