Hi Steve, yeah Burr means select the output surface and then turn on the surface control points, not turn on control points for the input curves.

If you want to experiement with that method for deforming the surface, you'll need to either delete the end caps of the revolve or turn off the "Cap ends" option when creating it so that you've got just one surface instead of something with multiple surfaces joined together, and then you'll be able to turn on its surface control points.

Also if you want to try that method, it may work better if you create a regular symmetrical revolve to start with instead of a rail revolve - a regular symmetrical revolve will get converted to a fully squishy surface by a kind of internal surface rebuild if you start pulling some of its control points around.

- Michael