These are curved concave and convex lenses, although it is the curved and constant curvature that gets me. If I do a lathe, the center will be ruined by pinching or ngon but the circumference will be circular. If I start with rounded cube for a perfect center I can no longer get a circular circumference. If I try to do nonlinear editing I will ruin the constant radius (curvature will change). Trying to do it using booleans will just create horrible geometry (this would be easy using CSGs).
Don’t know if this would suit you, since It has a hefty amount of modifiers for such a simple object, but hey, at least it works.
Make sure to check all layers as well as modifiers to see how this was configured to work. .blend
Well, I can’t believe I didn’t even consider shrink wrapping. Okay, so the result isn’t 100% perfect (the “corner quads” seem to produce oddity in shape when bridged) but it’s still miles better than my own attempts, thanks. I did try the ico sphere, but didn’t get anywhere. Note that I am a CAD guy, so Blenders approach to shape is not up my usual alley
What I have now will probably be sufficient, otherwise at least I know to try modifier approach.
If you’re not so worried about topology I could show you another way that this could be done with far less steps and modifiers. Seeing that you’re more of a CAD person, this wouldn’t be much of a problem for you now, would it???