1. Oncollisionenter2d Not Working
2. Oncollisionenter2d Not Being Called
3. Oncollisionenter2d Destroy Gameobject

They both look similar and behave similarly, what's then the difference between OnTriggerEnter and OnCollisionEnter? The key to understand this is in knowing what are triggers in Unity.

In Unity, an object might be controlled by the physics engine or by script. If you need to control an object by script but still would like to know if an object touched another, a 'collision' happened, you need to use triggers.

Collider2D.OnCollisionEnter2D(Collision2D) Leave feedback. Suggest a change. Thank you for helping us improve the quality of Unity Documentation. Although we cannot accept all submissions, we do read each suggested change from our users and will make updates where applicable. Help with OnCollisionEnter2D. I am having a really difficult time with collision detection in Unity. I have written a script with the function OnCollisionEnter2D. The main problem is that I am unable to enter the function! I have checked over and over for typos and potential solutions and have come up empty handed. Well, OnCollisionEnter2D (with parameter Collision2D) is one such method. It's a method that is fired (called) by Unity whenever it detects a collision between the object to which this script is attached to, and any another gameObject. Note the Collision2D col parameter we provided. If i do have an oncollisionexit2d method, both the enter and exit methods are called before the collider is able to pass through, essentially 'pushing' the moving collider out and not allowing it to pass through. Using boxcollider2d for door and circlecollider2d for player. Watch All C# Tutorials Here: 10 Games & Apps With Unity & C#: - ( Click On Show More ) -.

Collision is under quotes because, strictly under Unity's terminology, a collision only happens when object's movements are governed by the physics engine, for the other cases what we have are simply objects touching each other, also, for such event, our script can be alerted as well.

What are triggers

A trigger is a collider that's not influenced by the physics engine. It doesn't respond to forces nor gravity. But they still do have a use for the physics engine, they are used to detect whether an object passed through another. Triggers are everywhere in Unity game development, and in other engines too to be honest.

Oncollisionenter2d Not Working

Oncollisionenter2d Not Being Called

This Reaper is controlled by a simple back-and-forth walk AI, the physics engine is not used, but we still want to know when it has touched some things in the stage. For that, we can use an OnTriggerEnter

Collisions

A collision is also the result of an object touching another one, but instead of passing through, these objects push each other in a realistic way. Use OnCollisionEnter when your rigidbody colliders aren't triggers and you'd like to know when they touched each other.

Oncollisionenter2d Destroy Gameobject

For more information on how to create and use triggers, please see the official documentation on the subject. If you followed the documentation and something with your collision detection is not working, you may try to fix it using our comprehensive collision fixing tutorial.

TLDR;

Use triggers if you don't want/need the physics engine to control your object but still need to know if an object passed through another or reached some `zone` within the game. In that case, you'll use OnTriggerEnter().

If your object is indeed controlled by the physics engine, you'll use OnCollisionEnter() to know if an object touched another one.