Positioning Widget Based on World Object Position

[DarksBlood]

Hello everyone, I have something I hope I could get some help understanding.
So here how my set up works. I have A capsule which has a long cube as a child and on the cube is an empty game object at the very end of it. I'll refer to the capsule as the turret, the long cube as a barrel and empty as a Spawn Location. the barrel has the main camera attached to it as child as well. I managed to manually position a sprite on a 3d UI to represent where a projectile will land from the "Spawn Location"; 
However I want to do this with script and I have been really puzzled by this for a while now.

I've search and most people have suggested casting a ray and then using ray cast and worldtoscreenpoint.
Can I please get any suggestions on this please?

1. void Start ()
2.         {
3.                         RaycastHit Hit = new RaycastHit ();
4.                         Ray ray = CameraToUse.ScreenPointToRay (transform.position);
5.                         Debug.DrawRay (transform.position,Vector3.forward,Color.red);
6.                         if(Physics.Raycast (ray,out Hit))
7.                         {
8.                                 Vector3 Pos = CameraToUse.WorldToScreenPoint (Hit.point);
9.                                 Vector3 CrossPos = new Vector3(Pos.x,Pos.y,Cross.position.z);
10.                                 Cross.localPosition = CrossPos; // Set the parent of the spirte to the location
11.                                 print ("Pos " + Pos);
12.                         }
13.                
14.         }
15.  
16.  

[ArenMook]

Check the health bars sticky. It has the code you need to convert from world space to screen space.