[kaitai]

I agree with most of your comment, but the difference between bra fitting and shoe fitting is that you don't want to change the shape of your foot. Most women do want to change the shape of their breasts, even if not consciously: for instance, if your breast point outward & spread a lot, the fit of clothing is changed; if you have droopy breasts, you generally want to hold them up, again in the interest of clothing fit if nothing else; if you're involved in sports, you may want to create certain shapes to optimize your participation.

3D fitting would be really interesting, but not straightforward. It's hard to do the nonlinear transformation that would be necessary, partly because density of breast tissue varies a lot and so not all transformation functions would actually be possible. The "bloat" factor outlined in the article would also have an effect -- hormones, salt consumption, water consumption all affect that. 3D modeling might be most useful for placement of underwires, etc.