protected static void OnCameraChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
ViewportImage viewportImage = ((ViewportImage)obj);
viewportImage.RequestRender();
viewportImage.view = Matrix.LookAtRH(viewportImage.CameraPosition, viewportImage.CameraTarget, viewportImage.CameraUpVector);
}
/// <summary>
/// Handle request to re-render the scene from the 3D models.
/// Tell the ViewPort3D to re-render.
/// </summary>
protected void OnRequestRender(Object sender, EventArgs e)
{
viewport3DImage.RequestRender();
}