NullReferenceException: Object reference not set to an instance of an object PlacingParts.Update () (at Assets/Scripts/BuildingRocket/PlacingParts.cs:46)

Questions & Answers
1

I am getting an error where I call the function SnapTry. I think it has something to do with my array that I have. Can anyone help me find out the problem? If you need me to tell you about what the script does than I can and maybe I can find a better way to achieve what I’m trying to if this won’t work. Here’s the script:

using UnityEngine;
using System.Collections;

public class PlacingParts : MonoBehaviour 
{
	public static GameObject[] placedParts;
	private int i = 0;
	private Transform currentPart;
	public Transform centerPoint;

	private int partLayerMask = 1 << 9;
	private int snapPointLayer = 1 << 8;

	private bool hasPlaced;
	public float snapPointDistance = 0.75f;

	void Start () 
	{
		hasPlaced = false;
	}
	void Update ()
	{
		//HOW TO PLACE THE ITEM
		if (currentPart != null && hasPlaced == false)
		{
			//GIVES ME THE ABILITY TO MOVE THE PART/OBJECT THAT WAS JUST INSTANTIATED WITH THE PLACEITEM FUNCTION
			Vector3 m =  Camera.main.ScreenToWorldPoint (new Vector3(Input.mousePosition.x, Input.mousePosition.y, 12.9f +( MouseOrbitImproved.distance - 13.5f)));
			currentPart.position = new Vector3(m.x,m.y,m.z);

			//SET THE ITEM TO HAS PLACED SO THAT IT STOPS MOVING
			if(Input.GetMouseButtonDown (0))
			{
					hasPlaced = true;
					placedParts[i + 1] = currentPart.gameObject;
			}
		
		}
		//HOW TO PICK THE OBJECT BACK UP AFTER IT HAS BEEN PLACED
		Ray ray = Camera.main.ScreenPointToRay (Input.mousePosition);
		RaycastHit hit;
		
		if(Physics.Raycast (ray, out hit, Mathf.Infinity, partLayerMask))
		{
		
		} 
		SnapTry (currentPart, placedParts *.transform);*

  • }*

  •  void SnapTry(Transform obj1, Transform obj2) {*

  •  	//WHEN CALLING THE SCRIPT OBJ1 MUST BE THE CURRENTPART*

  •  	Transform[] transforms1 = obj1.GetComponentsInChildren<Transform>();*

  •  	//OBJ2 HAS TO BE AN ARRAY FILLED WITH ALL THE PLACED OBJECTS TRANSFORMS*

  •  	Transform[] transforms2 = obj2.GetComponentsInChildren<Transform>();*

  •  	foreach(Transform tr1 in transforms1) {*

  •  		foreach(Transform tr2 in transforms2) {*

  •  			if (tr1.tag == "SnapPoint" && tr2.tag == "SnapPoint") {*

  •  				if ((tr1.position - tr2.position).sqrMagnitude <= snapPointDistance) {*

  •  					Debug.Log ("You could snap an object here if the script was finsihed");*

  •  				}*

  •  			}*

  •  		}*

  •  	}*

  •  }*

  • public void PlaceItem(GameObject b)*

  • {*

  •  hasPlaced = false;*

  •  currentPart = (((GameObject)Instantiate(b)).transform);*

  • }*
    }

2

placedParts is null when executing line 46:

SnapTry (currentPart, placedParts *.transform);*

You will need to initialize placedParts or implement manual null and bounds checking.