void OnTriggerEnter(Collider other)
 {
     if (other.gameObject.CompareTag("headingTrig"))
     {
         other.gameObject.SetActive(false);
         rSolver.addCollisionPoint();
         poi poiScript = other.gameObject.GetComponent <poi>();
         if (poiScript != null)
         {
             poiScript.destroyMarker();
         }
     }
 }