Objects don't instantiate at mouse position

Question

I'm trying to get the player to shoot a projectile at the mouse position, however the projectile is shot in weird directions (http://gfycat.com/BothFluidHoneyeater).

Here is relevant part of my code:

var shotSpeed = 1000;
var projectile : Rigidbody;

function Update () {
    var clone : Rigidbody;
    if(Input.GetKeyDown(KeyCode.Mouse0)){
        clone = Instantiate(projectile, transform.position, transform.rotation);
    }
    clone.rigidbody.AddForce(Vector3.forward * shotSpeed);
}

What am I doing wrong?

Answer 1

First off, you should only be applying forces to rigid bodies inside the FixedUpdate method. You'll get more consistent results.

If you want objects to move in the direction another object is facing, you need to use transform.forward, not Vector3.forward. Alternatively you can multiply Vector3.forward by the quaternion of the rotation you want to use, like transform.rotation * Vector3.forward, this will output a Vector3 that's been rotated to face the same direction as the rotation you supplied.

The last thing to check is that your projectiles aren't colliding with the parent body that's spawning them. Since you're spawning the projectiles inside the parent body, you need to ensure they're not colliding, as that would produce strange results.