Problem running a function from another script c# help

Im trying to run a function Chop() from a separate script, the scripts are on different objects idk if that matters
i keep getting the error
NullReferenceException: Object reference not set to an instance of an object
chopped.OnTriggerEnter (UnityEngine.Collider col) (at Assets/Standard Assets/chopped.cs:20)

Code (CSharp):

1.  
2. public class Chop_wood : MonoBehaviour {
3.     public int inventory = 0;
4.  
5.  
6.     void OnTriggerEnter (Collider col)
7.     {
8.         Debug.Log ("at the tree");
9.         //Chop ();  
10.     }
11.  
12.    
13.     public void Chop()
14.     {
15.         inventory++;
16.         Debug.Log ("i am chopping the wood");
17.     }
18.  
19.     void Update ()
20.     {
21.    
22.     }
23. }
24.  

and here is the other script

Code (CSharp):

1. public class chopped : MonoBehaviour {
2.     public Chop_wood chopWood;
3.  
4.     void Start()
5.     {
6.         chopWood = GetComponent<Chop_wood> ();
7.     }
8.  
9.  
10.     void OnTriggerEnter (Collider col)
11.     {
12.  
13.         if (col.collider.name == "Pirate_Chopper")
14.         {
15.  
16.             Debug.Log ("in the trigger");
17.             chopWood.Chop();
18.         }
19.     }
20.    
21.     void OnTriggerStay (Collider other)
22.     {
23.            
24.     }
25.  
26. }
27.  

 

since the scripts are on different objects, you need a reference to the other object in the script calling for the function. using GetComponent<Chop_wood>() just looks for an instance of the script Chop_wood on its own object.

add something like public Transform otherObject; to the beginning of "chopped", and in the inspector, drop the reference to the object with "Chop_wood" in it.

then you should be able to do otherObject.GetComponent<Chop_wood>().Chop();

 

You can do this directly with the Chop_wood class - there's no need to go through the transform.

If you remove the Start function with the GetComponent call, you can drag the Chop_wood-containing object into that slot on the "chopped"-containing object.

 

oh yeah you could do public Chop_wood otherObjectsChopWoodScript; and just call the function from that

 

thanks, it works, lol i realized my problem soon after posting