How to use Edge Shape to create a curved surface?

Question

Java

Good day.
I can't understand how other people manage to create such curved surfaces in libGDX:
https://www.dropbox.com/s/g2jvtkeg830sk7n/tost%204...
I just managed to find only that they do this with EdgeShape , but how exactly they do it - failed. I will be very grateful to you if you can tell me how to make curved surfaces (like ChainShape, only with all sorts of curvature) in libGDX.
To make it clearer, here is the desired result that I would like to make. I have already made a similar machine, but it remains only to create a curved surface, with all kinds of bulges and humps.
Thank you in advance for your understanding.