How can I make an "aim System" for my tank game? (See where shell will land)

I follow the Tank-tutorial by Unity . Now I want to expand the game by making something like an aim system. I want to see where the shell of my tank is landing before I fired it.

Additional one important thing is that the landing point varies, when i have a bigger launchforce or less launchforce. (like in the two pictures), the code is the tankShooting.

using UnityEngine; using UnityEngine.UI;

namespace Complete { public class TankShooting : MonoBehaviour { public int m_PlayerNumber = 1; // Used to identify the different players. public Rigidbody m_Shell; // Prefab of the shell. public Transform[] m_FireTransform; // A child of the tank where the shells are spawned. public Slider m_AimSlider; // A child of the tank that displays the current launch force. public AudioSource m_ShootingAudio; // Reference to the audio source used to play the shooting audio. NB: different to the movement audio source. public AudioClip m_ChargingClip; // Audio that plays when each shot is charging up. public AudioClip m_FireClip; // Audio that plays when each shot is fired. public float m_MinLaunchForce = 15f; // The force given to the shell if the fire button is not held. public float m_MaxLaunchForce = 30f; // The force given to the shell if the fire button is held for the max charge time. public float m_MaxChargeTime = 0.75f; // How long the shell can charge for before it is fired at max force.

     public bool shellBoost = false;
     public float m_PlusDamage = 0;
     public float m_PlusExplosionForce = 0;

     private string m_FireButton;                // The input axis that is used for launching shells.
     private float m_CurrentLaunchForce;         // The force that will be given to the shell when the fire button is released.
     private float m_ChargeSpeed;                // How fast the launch force increases, based on the max charge time.
     private bool m_Fired;                       // Whether or not the shell has been launched with this button press.
     private float startMinLaunchForce;
     private float startMaxLaunchForce;
     private float startChargeSpeed;


     private void OnEnable()
     {
         // When the tank is turned on, reset the launch force and the UI
         m_CurrentLaunchForce = m_MinLaunchForce;
         m_AimSlider.value = m_MinLaunchForce;
     }


     private void Start ()
     {
         // The fire axis is based on the player number.
         m_FireButton = "Fire" + m_PlayerNumber;

         // The rate that the launch force charges up is the range of possible forces by the max charge time.
         m_ChargeSpeed = (m_MaxLaunchForce - m_MinLaunchForce) / m_MaxChargeTime;

         startMaxLaunchForce = m_MaxLaunchForce;
         startMinLaunchForce = m_MinLaunchForce;
         startChargeSpeed = m_ChargeSpeed;
     }


     private void Update ()
     {
         // The slider should have a default value of the minimum launch force.
         m_AimSlider.value = m_MinLaunchForce;

         // If the max force has been exceeded and the shell hasn't yet been launched...
         if (m_CurrentLaunchForce >= m_MaxLaunchForce && !m_Fired)
         {
             // ... use the max force and launch the shell.
             m_CurrentLaunchForce = m_MaxLaunchForce;
             Fire ();
         }
         // Otherwise, if the fire button has just started being pressed...
         else if (Input.GetButtonDown (m_FireButton))
         {
             // ... reset the fired flag and reset the launch force.
             m_Fired = false;
             m_CurrentLaunchForce = m_MinLaunchForce;

             // Change the clip to the charging clip and start it playing.
             m_ShootingAudio.clip = m_ChargingClip;
             m_ShootingAudio.Play ();
         }
         // Otherwise, if the fire button is being held and the shell hasn't been launched yet...
         else if (Input.GetButton (m_FireButton) && !m_Fired)
         {
             // Increment the launch force and update the slider.
             m_CurrentLaunchForce += m_ChargeSpeed * Time.deltaTime;

             m_AimSlider.value = m_CurrentLaunchForce;
         }
         // Otherwise, if the fire button is released and the shell hasn't been launched yet...
         else if (Input.GetButtonUp (m_FireButton) && !m_Fired)
         {
             // ... launch the shell.
             Fire ();
         }
     }


     private void Fire ()
     {

         // Set the fired flag so only Fire is only called once.
         m_Fired = true;
             // Create an instance of the shell and store a reference to it's rigidbody.
             for (int i = 0; i < m_FireTransform.Length; i++)
             {
                 Rigidbody shellInstance =
                 Instantiate(m_Shell, m_FireTransform[i].position, m_FireTransform[i].rotation) as Rigidbody;
                 shellInstance.velocity = m_CurrentLaunchForce * m_FireTransform[i].forward;

             if (shellBoost)
             {
                 shellInstance.gameObject.GetComponent<ShellExplosion>().m_MaxDamage += m_PlusDamage;
                 shellInstance.gameObject.GetComponent<ShellExplosion>().m_ExplosionForce += m_PlusExplosionForce;
             }
         }

         // Change the clip to the firing clip and play it.
         m_ShootingAudio.clip = m_FireClip;
         m_ShootingAudio.Play ();

         // Reset the launch force.  This is a precaution in case of missing button events.
         m_CurrentLaunchForce = m_MinLaunchForce;
     }

Thank you

Please excuse my bad english...