Rendering in controllers vs rendering in views

Hello, can someone experienced please explain to me what are the main differences between the `render` methods in `ActionController` and in `ActionView`? I mean: arguments, internal working, purpose, rendering "layouts", what are the differences?

I am looking into this because i want to better understand what `render` does with its block, and if it is different when passing a block to `render` in a controller or in a view.

I would like to be able to do something like this, but so far haven't been successful:

render "sublayout_of_the_application_layout" do
  render "sublayout_of_the_sublayout" do
    render "my_view_here_rendered_in_three_nested_layouts"
  end
end

Thank you. Alexey.

I have already received responses here: http://railsforum.com/viewtopic.php?id=47996