private void Grid_MouseDown(object sender, MouseButtonEventArgs e){    DoubleAnimation da = new DoubleAnimation();    da.Duration = new Duration(TimeSpan.FromSeconds(1));    if (e.ClickCount == 2)        da.To = 0d;    else        da.To = 180d;    AxisAngleRotation3D aar = Application.Current.MainWindow.FindName("aar") as AxisAngleRotation3D;    aar.BeginAnimation(AxisAngleRotation3D.AngleProperty, da);  }