Handles.Button  

static function Button (position : Vector3, direction : Quaternion, size : float, pickSize : float, capFunc : DrawCapFunction) : boolean

Description

Make a 3D Button.

This works like a normal GUI.Button, but it has a 3D position and is drawn by a handle function

Note: Use HandleUtility.GetHandleSize where you might want to have constant screen-sized handles.

Button Handle as a rectangle in the Scene View.

// Create a simple button on 3D space and when the user clicks over the handle
// it prints a message.

@CustomEditor (ButtonChecker)
class ButtonHandle extends Editor {
    function OnSceneGUI () {
        target.checkButton = 
            Handles.Button(target.transform.position + Vector3(0,2,0),
                    Quaternion.identity,
                    3,
                    3,
                    Handles.DrawRectangle);    
    }
}

And the script attached to this handle:

// Usage: Place this script on the object you want to create the button on.
// When the script is placed, just press "Play" and click the rectangle
// that appears over the GameObject

var checkButton : boolean = true;

function Update() {
    if(checkButton)
        Debug.Log("The handle button has been pressed!");
}