Hi @freelancer,
Thank you very much I also use google translate a lot. However, the internet is a wonderful place. If you right-click on the page, there is a menu that pops up that gives you the option to translate the page, which makes me really lazy.
There are a few very good topics on the forum about making curves and this one is one of my favourites that got me creating curves nicely: Another "very mathematical" way of making curves!.
And then here is a very nice tutorial on bra pattern making, that may interest you, where @AVI has given the formulas for the curves: Kristina Shin Basic underwire bra tutorial - #8 by MrDoo.
I hope that this will help you to understand the process a bit better to create your curves smoothly and easily.