OnTriggerEnter/Exit called unexpectedly

Questions & Answers
1

Hi,
I have a capsule(the NPC body) with a cone mesh attached(their sight). This sight cone has attached a trigger collider and a kinematic rigidbody. This NPC is patrolling, so he walks and looks around. The problem is that I’m using another capsule(the player), which has both a collider(not trigger) and a kinematic rigidbody, to test the NPC sight(basically, I’m moving this character so to enter the field of view of the NPC), but OnTriggerEnter/Exit on the sight cone on the NPC is called unexpectedly: when the player capsule enters the trigger mesh of the NPC, suddenly onTriggerEnter and onTriggerExit get called twice each(and yes, in both onTriggerEnter and onTriggerExit i check that the object entering/leaving is the player collider). The same thing happens when the player collider leaves the trigger mesh of the NPC, onTriggerEnter and onTriggerExit get called twice each.

To make things a bit clearer, this appears in the Console:

Player Entering
Player Entering
Player Leaving
Player Leaving

Does anybody have any idea about what’s going on here?

3

Hy,

This is because Physics can be called multiple times before each update method.
I had a very similar issue and my solution was something like that:

function OnCollisionEnter (collision : Collision) {
     if(!collisionAlreadyTracked) {
          // collision related code...
     }
    collisionAlreadyTracked = true;
}

This simple statement basically prevents these events to be tracked multiple times per frame.
I guess there is a more sophisticated way to handle this, so it is just a quick workaround, but its working. :slight_smile: (until you (and me as well) get a better solution)

2

why dont u attach an empty game object with a box collider to your gameObject and use the box collider to check if OnTriggerEnter is called box colliders work far better than capsule colliders