help me blow my balloon....

I am trying to create a prototype of a balloon that can me affected on a 2D plane by the users mouse clicks. Depending on the location i want to fire an AddForce function to push the balloon AWAY from the users click. here's what i'm trying to work with...

if (Input.GetButtonDown ("Fire1")) {
        // Construct a ray from the current mouse coordinates
        var ray = Camera.main.ScreenPointToRay (Input.mousePosition);

           var objVect: Vector3;

           var mouseVect: Vector3;

           mouseVect[0] = (Input.mousePosition.x);
           mouseVect[1] = (Input.mousePosition.y);
           mouseVect[2] = (0);

           print ("mouseVect is " + mouseVect);

           objVect[0] = (myRigidBody.position.x);
           objVect[1] = (myRigidBody.position.y);
           objVect[2] = (0);

           if (Physics.Raycast (mouseVect, objVect))
              var forceX;
              var forceY;

              var multiplyer = .05;

              forceX = ((Input.mousePosition.x) - (myRigidBody.position.x)) * multiplyer;
              forceY = ((Input.mousePosition.y) - (myRigidBody.position.y)) * multiplyer;

              //print ("forceX is " + forceX);
              //print ("forceY is " + forceY);

              myRigidBody.AddForce (forceX, 0, 0);
              myRigidBody.AddForce (0, forceY, 0);
           }
     } 

I think the problem is that i want to use the AddForce(Physics.Ratcast(mouseVect, objVect)) as my force but don't know how that's done.

Any help would be AWESOME!!!

Just replied on your forum post but as this is meant to be the place I'll reply here too:

OK, looking at the docs this function that andeeee mentioned before is what you need.

http://unity3d.com/support/documentation/ScriptReference/Camera.ScreenToWorldPoint.html

This effectively does the raycasting/collision with the plane for you (which is the long way around I was suggesting before).

However, you need to set a Z position for it (which was missing before) - this is the distance forward from the camera. In your case you want that to be the Z position of the balloon relative to the camera.

So:

public var pushForceMultiplier:float=100.0; // you'll want to tweak that

function Update(){

    if(Input.GetMouseButtonDown(0)){
    // left click

      var camDist=rigidbody.position.z-Camera.main.transform.position.z;

      var clickPoint=Camera.main.ScreenToWorldPoint(Vector3(Input.mousePosition.x,Input.mousePosition.y,camDist)); // screen click point on the same Z distance from the camera as your rigidbody

      var vec=rigidbody.position-clickPoint; // the direction from clickPoint to the rigidbody
      vec=vec.normalized;

      rigidbody.AddForce(vec*pushForceMultiplier);

    }

}

NB. This is written as a script you attach to the balloon, rather than something you set a variable on linking to it.