Rendering using vtkRenderWindowInteractor

I am using Activiz ( VTK for .NET ) version 5.8. My application is to render a real-time 3D Point cloud. I want to do the whole rendering using vtkRenderWindowInteractor. But currently, I can only use it at the start of the rendering, not the whole time. After that is uses vtkRenderWindow in which I can’t change the view using a keyboard/mouse.