// Create a 180 degrees wire arc with a ScaleValueHandle attached to the disc
// that lets you modify the "shieldArea" var in the WireArcExample.js, also
// lets you visualize some info of the transform and finally lets you
// reset the shield area value to 5 by clicking on a button

@CustomEditor (DummyButtonScript)
class GUIButtonHandle extends Editor {
function OnSceneGUI () {
Handles.color = Color.blue;
Handles.Label(target.transform.position + Vector3.up*2,
target.transform.position.ToString() + "\nShieldArea: " +
target.shieldArea.ToString());
Handles.BeginGUI(Rect(Screen.width - 100, Screen.height - 80, 90,50));
if(GUILayout.Button("Reset Area"))
target.shieldArea = 5;
Handles.EndGUI();

Handles.DrawWireArc(target.transform.position,
target.transform.up,
-target.transform.right,
180,
target.shieldArea);
target.shieldArea =
Handles.ScaleValueHandle(target.shieldArea,
target.transform.position + target.transform.forward*target.shieldArea,
target.transform.rotation,
1,
Handles.ConeCap,
1);
}
}

// DummyButtonScript.js

var shieldArea : float = 5;