Using multiple triggers as one trigger zone

Questions & Answers
1

I have a 3-room area within my game, and none of them are simple shapes. What I’m trying to do is have separate background noise for each room, and fade them out when you leave one area and fade in when you enter another - it almost works. I have created multiple box triggers per room to create the different zones, and attaching all the game objects together under a parent running the script and the audio. The script is basically onTriggerEnter and Exit commands, but the triggers are going off whenever I cross boundaries from different triggers within the same zone. I thought that when you added colliders as children, they formed one complete trigger area - perhaps I am mistaken, or perhaps I am doing it wrong! I would appreciate any help.

public class MusicManager : MonoBehaviour {
	
	public float musicFadeSpeed = 4.0f;
	public float musicVolume = 0.4f;
	public bool fadeUp;
	public bool fadeDown;
	
void awake ()
	{
		fadeUp = false;
		fadeDown = false;
	}

void OnTriggerEnter(Collider col)
	{
		if(col.gameObject.tag == "Player")
		{	
			Debug.Log ("Set fade in to true");
			fadeDown = false;
			fadeUp = true; 
		}
	}
	void OnTriggerExit(Collider col)
	{
		if(col.gameObject.tag == "Player")
		{
			Debug.Log ("Set fade out to true");
			fadeUp = false;
			fadeDown = true;
		}
	}
	
	void Update()
	{
		Debug.Log ("Test up?");
		if(fadeUp == true)
		{
			Debug.Log ("Ready to fade!");
			FadeIn ();
		}
		
		Debug.Log ("Test down?");
		if(fadeDown == true)
		{
		Debug.Log ("Ready to fade!");	
		FadeOut ();	
		}	
	}
	
	void FadeIn ()
	{
		fadeDown = false;	
		Debug.Log ("Should be fading in!");
		audio.volume = Mathf.Lerp(audio.volume, 0.5f, musicFadeSpeed * Time.deltaTime);
	}
	
	void FadeOut ()
	{
		fadeUp = false;
		Debug.Log ("Should be fading out!");
		audio.volume = Mathf.Lerp(audio.volume, 0f, musicFadeSpeed * Time.deltaTime);	
	}
	
	
}
2

I, too, have wondered about this in Unity. In the Source engine, for example, you can create multiple brushes and tie them all together as a single entity (and thereby a trigger collision will only fire when the player enters into the entirety of the volume, rather than separate collisions firing for each component brush).

A workaround:

Create a custom-shaped mesh in a modelling program to be the custom trigger shape that you need. Use this mesh as the physics collider mesh.

This involves a bit of extra work going back and forth between Unity and your modelling program, but it should work fine.

Another workaround:

Update your script to deactivate the parent gameObject after void OnCollisionEnter() has been fired. This way, one trigger will send an output, then they will all be disabled.

To reuse the set of trigger volumes, you will have to re-enable the parent object after the player collides with another trigger set.

One potential bug: if the player collides with two trigger volumes in the same frame, it may still fire twice.