Hellow,

I have a code to switch a simply boolean on Enter and Exit, the thing it only work once.

Here is the two concerned function and the Boolean var.

var CanLaunch : boolean = false;

function OnTriggerEnter (ball) {
    CanLaunch = true;   
}

function OnTriggerExit (ball) {
    CanLaunch = false;  
}

On the first, enter it turn launch, and on the first exit it turn it false. But if the ball enter it again, it doesn't turn true again.