How to detect a character is leaving a 3D world?

Questions & Answers
1

I have an open world 3D game where my character will run around and if he gets too close to the edges he will hear a geiger counter, his eyes will start to close & eventually start to die from the radiation. My problem is I don’t know how to enclose my world in a “ring” collider to trigger my code to do this. I have seen suggestions to use ProBuilder Basic but I would hate to bring in yet another whole new asset just to solve this.

3

all you need to do is check the distance of the player from the center of the level.
here is a 2D distance function:

	public bool die;
    public Vector3 center = Vector3.zero;//<-center of level here
	public float ringsize = 20;//<-size of ring

	float timer = 0;
	void Update(){
		timer += Time.deltaTime;
		if(timer>1){timer-=1;
			die=false;
	if (distance (transform.position, center) < ringsize) {
				die=true;
			}}}
	public float distance (Vector3 v1, Vector3 v2){
		
		float f1 = v1.x - v2.x;
		float f2 = v1.z - v2.z;
		f1 *= f1;f2 *= f2;
		return Mathf.Sqrt(f1+f2);}
2

The easiest would be to use a giant sphere and react to it on OnTriggerEnter and OnTriggerExit. Or you just check the distance of the character each or every other frame from the center.