private void Rect3DTo2DButton_OnClick(object sender, RoutedEventArgs e)
{
Rect screenRect = _selectedCamera.Rect3DTo2D(new Rect3D(new Point3D(-20, -20, -20), new Size3D(40, 40, 40)));
MessageBox.Show(string.Format(System.Globalization.CultureInfo.InvariantCulture,
"Calling:\r\nRect3DTo2D(new Rect3D(new Point3D(-20, -20, -20), new Size3D(40, 40, 40)):\r\n\r\nResult:\r\nscreenRect: {0:0.0}",
screenRect));
}