I've read recently that dentists no longer need to get a physical imprint / make a form in order to produce a (anti-clenching etc.) mouth guard - they can just do some sort of 3D scan of the teeth (can't remember if it was video- or X-ray based). Couldn't similar technology be used for bra fitting? (Though I imagine it would be complicated by e.g. breast size depending on the menstrual cycle phase, etc.). A coarse-grained "structured-light" 3D body scan should be quick and convenient to do.
It would be a bit like using LiDAR and photogrammetry to measure lumber for furniture making. It's not that it wouldn't work, it's just that you can ask any builder and they'll tell you that it's easier to use a tape measure. But the problem isn't really eyeballing vs measuring. It's what's in stock.
The economics of size availability is the problem. Think of a lumber yard that only keeps square lumber (1x1s, 2x2, 4x4s) in stock and tells customers they can laminate two 2x2s with wood glue to get a 2x4 or split a 4x4 in half. Yes, you can, but it would be great if the 2x4s we're kept in stock.
Now multiply the problem across band and cup size. Sister sizes are a way to project a two-dimensional inventory problem into one dimension and that's the root of the issue.
It's not unlike the average cockpit problem[1], but applied to bras. The first person to make an adjustable cup size bra that's comfortable and fashionable will make a fortune.
It is video. The handheld portion is shaped roughly like a pen, with a cable attached to a computer & monitor. The lens end is rubbed across your teeth and a 3D image is made.
It had to be rubbed rather firmly against my teeth & gums. Doing so against breasts would be painful. I've had rather severe gynecomastia since I was 11. In my 30s, I'd sometimes wear a bra when doing sports. I wore a 38B/36C (depending on the brand of bra).
