protected override void constructed()
 {
     sceneNode = Owner.getElement(nodeName) as SceneNodeElement;
     if (sceneNode == null)
     {
         blacklist("Cannot find scene node named {0}.", nodeName);
     }
     manualObject = sceneNode.getNodeObject(manualObjectName) as ManualObject;
     if (manualObject == null)
     {
         blacklist("Cannot find manual object named {0}.", manualObjectName);
     }
     manualObject.setVisible(drawLines);
     manualObject.begin("Grid", OperationType.OT_LINE_LIST);
     manualObject.position(ref Vector3.Zero);
     manualObject.color(0, 0, 0, 0);
     manualObject.position(ref Vector3.Zero);
     manualObject.color(0, 0, 0, 0);
     manualObject.end();
     MeasurementController.setMeasurementDrawer(this);
 }
 protected override void destroy()
 {
     MeasurementController.setMeasurementDrawer(null);
 }