Hi Anthony,

> I was watching the videos and I say when you update the
> rails the sweep will update. But when I tried it nothing updated.

Are you trying it after you've done other operations to the result of the sweep like booleaned them?

If so then, that's the difference - some kinds of operations can break the "history chain" that connects curves to their generated descendents.

If you do the editing immediately after doing the sweep before you do other operations to it, that's when you should be able to see the update happen.

In the future I do want to make the history function deeper and persist through more kinds of operations, that is a complex area to handle well though.

- Michael