Hello sewing friends!

I have a question that I have been wondering about—in lingerie and shapewear, I occasionally see pieces made of mesh or other stretch material that form to the curves in the body, yet they have no shaping darts or seams. Specifically I am thinking of bra cups which must accommodate the dramatic curve of the bust without flattening it. I have mostly seen this technique in commercially produced garments, so maybe it has to do with some kind of special equipment which manipulates and warps the shaping of the fabric, but maybe it is something simpler than this that I am missing.

Does anyone have any insight?

Thanks!