How to detect raycast exiting

Questions & Answers
1

I have this script that detects when a raycast hits an object and runs a function from that gameObject.

How can I detect when the raycast leaves the object so I can run a different function to that gameObject?

using UnityEngine;
using System.Collections;

public class CastRays : MonoBehaviour {

	SetRenderQueue srq;

	void FixedUpdate()
	{
		RaycastHit hit;
		Vector3 forward = transform.TransformDirection (Vector3.forward) * 7;
		if (Physics.Raycast (transform.position, forward, out hit) && hit.transform.tag == "Block") {
			print ("There is something in front of the object!");
			srq = hit.transform.gameObject.GetComponent<SetRenderQueue> ();
			srq.MakeTransparent (); //Run Function
		}
		Debug.DrawRay(transform.position, forward, Color.green);
	}
}
2

It looks like you are holding a reference to the last SetRenderQueue. So you know what the previous object was so before setting that variable again compare it and if it is different call another method before setting it to the new version.

....
print("There is something in front of the object!");
SetRenderQueue tempSrq = hit.transform.gameObject.GetComponent<SetRenderQueue>();
if(tempSrq != srq) {
    srq.MakeOpaque();
    srq = tempSrq;
}
srq.MakeTransparent(); //Run Function