I’ve created these curves for the vial. As you see it has offset curves for 2-sided glass properties. But when I revolve the whole curves, it creates a single-side vial. Why?
T.3dm (419.9 KB)
As the ends of each curve match the center of the revolution, there is not intersection between the resulting surfaces. that’s why.
To model a bottle with thickness, there is no other way than open it in some place, at the top, for example.