Unity 2D: Destroy object with dynamic collider after exiting object with static collider

Question

I'm using the Unity5 game engine and am programming a 2D shooter in bird's eye view.

I have a static Box Collider 2D which covers the entire game area.

It has "Is Trigger" checked and contains a very simple script which should destroy every object that exits it.

 using UnityEngine;
 using System.Collections;

 public class DestroyByBoundary : MonoBehaviour {
     void OnTriggerExit(Collider other) {
         Debug.Log ("OnTriggerExit");
         Destroy (other.gameObject);
     }
 }

The player character shoots bullets which have a dynamic Circle Collider 2D.

However, the bullets are never destroyed when they leave the game area and just fly on indefinitely. The debug statement never gets executed either, of course. I have tried the same thing with OnTriggerEnter, which yields the same result.

If any more information should be needed, I'll be happy to provide it.

Answer 1

As DMGregory has pointed out in a comment, I was using 3D objects and methods in a 2D environment.

I had to change the parameter of the script to a Collider2D object and use the OnTriggerExit2D method.

 using UnityEngine;
 using System.Collections;

 public class DestroyByBoundary : MonoBehaviour {
     void OnTriggerExit2D(Collider2D other) {
         Destroy (other.gameObject);
     }
 }