Its based on a combination of standard metrics (avg pupil size, axial lenght, etc) and their own fudge factors.
They will all be different, but only slightly so, there is no way to pick up a Aspheric SV lens examine it, and even tell who made it (unless you can identify the AR, or it has markings).
The Essilor 360 is an asheric SV blank cut on a digital generator. It's kind of like the Physio 360's and Ellipse 360. Zeiss first coined the term Free-form in 1997 to describe only the atoric back curve of the first Individual.
Although Shamir trademarked Free Form, they didn't invent it. Technology TM analyzes wavefront distortions (propagation of light) and corrects optical aberrations.
Hmm, mukhang babalik na ata uli ang dating old glory ng Cavite City.