Hi Don, to use the Transform > Deform > Flow command you need 3 objects - your object that you want to deform, then the base backbone curve (usually a line) and then a target backbone curve.

It looks like you only have 2 curves there, the problem is you're missing the base backbone curve. That would be a line running down the middle of your helix.

Once you have that, then the process is: select curve you want to deform (your helix), then select the first backbone curve (the line down the middle of the helix that you are currently missing) then the target curve (the circle).

- Michael

Fantastic! Thanks Michael. Here is a screen capture before selecting done with stretch checked.

Well, that was super easy in MoI! Thanks for your assistance Michael.

You're welcome Don!

- Michael

Don't know if you are interested but here is the MoI model exported out to Alibre and rendered in KeyShot

It is a beauty!

There is also the ToroidalHelix script.

- Brian