Problem with Instantiate() Function in C#

Questions & Answers
1

Hi all.
I want to instantiate a bulb when a collision enter. but OnTriggerEnter() works
correctly but when I add a piece of code that Instantiate a Object the compiler show some errors:

(Filename: Assets/MyScripts/Animals.cs Line: 21)

Assets/MyScripts/Animals.cs(21,25): error CS1502: The best overloaded method match
for `UnityEngine.Object.Instantiate(UnityEngine.Object, UnityEngine.Vector3,
UnityEngine.Quaternion)’ has some invalid arguments

(Filename: Assets/MyScripts/Animals.cs Line: 21)

Assets/MyScripts/Animals.cs(21,25): error CS1503: Argument #1' cannot convert object’ expression to type `UnityEngine.Object’

(Filename: Assets/MyScripts/Animals.cs Line: 21)

the code is:
bullet sp = Instantiate( bullet, transform.position, transform.rotation); sp.transform.localScale.Scale(new Vector3(radius , radius , radius));

I have read the Script reference and Documentation but i confused why this code has type conversion error.
please Help me.
thanks for your help.

2

You need to give the Instantiate function a Unity object (usually a prefab) from which unity will create the new instance.
In the following case:

bullet sp = Instantiate( bullet, transform.position, transform.rotation);

You have actually tried to create an instance using the type definition (“bullet”).
You can not do that.
You could however do something like the following:

// In the edito, create a prefab of type bullet and drag it to the GameObject on which you have attached this script
public bullet referenceToBulletPrefab;

void OnTriggerEnter(Collider other)
{
   // Put here the rest of the code

   // Create a new instance of a bullet using the prefab: referenceToBulletPrefab
   bullet sp = Instantiate( referenceToBulletPrefab, transform.position, transform.rotation);

   // Put here the rest of the code
}
3

Thanx for your answer but the problem when occured the Instantiate() return UnityEngine.Object and isn’t a prefab such as bullet!! I’m hanging on it!!!

4

You can still use C#, if you want. Most people in javascript use untyped variables, which works great when you don’t know the type. You get to say:

public bulletPrefab : Transform;

newbullet = Instantiate( bulletPrefab ..... );
newbullet.regidbody.velocity = ....

We don’t know what type the instantiated bullet is, but whatever it is, newbullet is declared as one of those. In C#, you just have to know Instantiate returns a gameObject, and how to convert that to a Transform (this is in the Instantiate ex in the Unity manual, if you switch it to C#):

Transform newbullet = Instantiate(bulletPrefab .... ) as Transform;
newbullet.rigidbody....   // can now use it like a normal Transform