Collision Detection Problems?

Unity Engine
1

So I have this script, I have a box collider on it, and a box collider on my enemy, but it doesn’t want to work, is there something wrong with my script? I even tried putting a rigidbody on my enemy but to no avail. Not even my first Debug.Log is being called.

var damage : float = 5;

function OnCollisionEnter(hit : Collision){
Debug.Log("Collided");
if(hit.collider.tag == "enemy"){
Debug.Log("Hit Enemy");
AI = hit.collider.GetComponent(NinjaAI);
AI.LoseHealth(damage);
}
}

EDIT: Wow I feel stupid, nevermind I got the first Debug.Log working, so now it collides it just doesn’t recognize the tag for some reason. and yes my enemy is tagged “enemy”.

2

It’s not tagged “Enemy”, is it?

Also, the collider component of a collision object is different than the actual Collider component, I think, and I’m not sure you can access the usual inherited members, like “tag” from it. I might be wrong though.

Try:

if(hit.gameObject.tag == "enemy"){
3

Yeah it was tagged “Enemy” but I just changed it to “enemy” with no change. hit.tag returns the error “tag is not a member of UnityEngine.Collision”. And I know hit.collider.tag works because I use it on my bullet script. But the difference is that my bullet has a rigidboy whereas my melee weapons do not because then they either float away(no gravity) or the drop through the ground (gravity).

4

Try this:

if (hit.collider.gameObject.tag == "enemy")

Or as an alternative you can use CompareTag

5

Sorry, I posted prematurely, I had edited my post to say hit.gameObject.tag, but you had already read it. You could try giving your weapons rigidbodies and try freezing rotation and/or is kinematic, they shouldn’t float away then.

Does your enemy have a rigidbody? OnCollisionEnter only registers collisions if one or both of the colliders has a rigidbody attached.

6

Thanks a lot for the tip on the rigidbodys, that had stumped me for a while. I tried CompareTag but that still didn’t work, I really have no idea what’s wrong with it. Thanks for trying to help.

7

Ok I got it working, I used OnTriggerEnter instead and for some reason the tag (even though I’m sure I did it lowercase) only responds when I match it against “Enemy”. But whatever. Anyway, how I got it to work was I made a debug.log that when collided with something it said "Collided with " + hit.collider.tag, and I found out it was hitting the enemy, but the tag was returning as Enemy. It’s all working now, thanks for the help! :slight_smile:

Here’s the working script in case anyone is interested

var damage : float = 5;
var player : Transform;

function Update(){
Physics.IgnoreCollision(this.collider, player.collider);
}

function OnTriggerEnter(hit : Collider){
//Debug.Log("Collided With " + hit.collider.tag);
if(hit.gameObject.CompareTag("Enemy")){
var AI = hit.collider.GetComponent(NinjaAI);
AI.LoseHealth(damage);
}
}