You flatter me, Spongeworthy. I've never had anyone say Adobe Illustrator, Photoshop and Woodturner PRO in the same paragraph. Boy, are you ever going to be disappointed. But thanks for the good laugh.
You also had me going there for a bit about various other turning design software. There are only two and anyone I know that has them both uses only one of them. I'll let you guess which one that is. I am the only one in the world currently writing software for segmenters.
You are WAY to fixated on Undo. When you're designing a vessel what is it that you think you have to undo? If you don't like the shape, you just edit the wall profile and click Profile-SNAP and you have a complete new design. In Segment PRO, once you've created all of your adornments, you can simply change profiles and your adornments are now part of the new design. If you change from 16 to 20 segments and don't like it, change back to 16. If I even thought that Undo was necessary, I would spend the time it takes to write it on new functionality that adds value.
BTW, if you are just starting out, you should be using Segment PRO because I wrote that software for people new to segmenting. If you haven't watched any of the video tutorials, click this link:
Title: Segment PRO
Segment PRO is kinda like an autonomous car. It does all the work for you. You just have to select (or draw) a profile and stand back. I can't even imagine why you would want an Undo feature except for the Paint screen and there is one there already. Segment PRO lets you design about 90% of the vessels that are made every day. Woodturner PRO lets you design almost anything you can imagine but you have to do all of the work. Customers that have them both know exactly when you should use one or the other because they are night and day different.