I visited a thread and saw a dear designer’s work. He even sent his Rhino file that I downloaded and opened it. I noticed he used a sphere as his curvature surface base.
It was a lesson for me, but as I usually work with my method, I deleted all the surfaces that he made and kept the accurate sketch of the glasses.
I didn’t use a sphere but made the curvature surfaces with three separate single surface spans, and then did projection and other works. I don’t know, is it confirmed by the dear designer or not, but I just know his work would be more accurate and detailed than what I made.
I usually try to learn whatever attracts my mind ( mostly through visual review and exercise), and your post excited my interest, as well
So you are the professional designer of glasses frames? Nice!
You pointed out that the glasses designers use a sphere as a standard base to create 3D models for extrusion. What about the glasses frames that have a flattened shape approximately?