As I said, I made arcs my ally in the battle with the bra drawing. Looks like we are winning
Here is how two corresponding curves scale in different sizes. See this little pink thingy with A51 mark? That’s the difference between their length. It’s less than 0.15 cm in every size I tried
I don’t think I can make a step-by-step tutorial of how to do this with any curve. It is a creative process. You make tangents and points on them, then you draw perpendiculars and see where they cross, use the distance from points on curves to crossing points to find arc centers. Something like that. You also use Line * x type of formula a lot.
I mastered this so I don’t even need a Bezier curve to start with
It’s very flexible too, the only thing I can’t change freely (without history tab and lots of caution) is number of arcs in each curve)