A few more comments:
1. The current version (v6) of Invig has an Object Drawing panel in the Invigorator Set-Up window.
You can create extruded and lathe objects in this window (Ctrl+L to create a Lathe object on the PC - Cmd+L on the Mac).
2. When creating outlines in Illustrator and saving the file, make sure "Use Compression" is off in the Save options.
3. If you draw a quarter circle as an extruded object, or import a quarter circle Illustrator outline, you can convert it to a Lathe object using the Object menu.