Thanks a lots Sebastien,
May I ask another question. I want to implement a 3D remote rendering system. Server will render 3D images and only returns 2D images to the client. So client only gets 2D images instead of whole 3D images. In the example : examples/03_applications/vtk-f1-picking/app.py), I see that client still consumes the while 3D images (f1.vti), any only communicate with server with points. Do you have an example of illustrating server returning 2D images each time client calls (for example clients calls rotate object, cut objects, …) ?