Make a tool “flange” that gives the possibility to realize a flange starting from a curve (closed or open). Can extrude and rotate through input and graphically (visually) and to submit the handles intermediate in such a way as to create a flange variable trend.
An example of what I mean you can see it in the last part of the attached video, taken from the software “Autodesk Alias Design”, under "Multi-surface Draft."
Thanks for the feedback. There’s a lot here that is different from how Rhino currently works. My very first thought was to use Grasshopper. This wouldn’t be a modal dialog with defined feature settings but it is an option and can be very flexible. Another thought was using Sweep and Mirror back to back with history enabled. Have you tried that? Here’s a sample of what I mean… SweepMirror_History.3dm(269.4 KB)