Measure Once

Buyer films the window. Seller sends the right size. I make wooden curtain poles and sell them on Etsy: Creationsfromrob, open since 2020, nearly 800 sales and 4.7 stars from 119 reviews (https://www.etsy.com/shop/creationsfromrob). This is my real inbox and my real catalogue. Every pole is cut to fit, and a cut pole can't come back, so a wrong measurement costs a whole order. About 1 in 4 of my buyer threads ask which size to order, and they wait a median of 10 hours for my answer. Measure Once is the sizing desk I wanted, plus one link I send any buyer who asks which size. The buyer opens it on their phone, tapes a sheet of A4 (or US Letter) flat on the wall and films the window for a few seconds, saying what they want. SAM 3.1 finds the sheet and the window in the sharpest frames, and on full clips tracks their hands. My code turns pixels into centimetres from the sheet's known size and the window's straight edges. Muse Spark Open, Meta's open-weights model on Baseten, looks at the edges the code found on the wall and picks the pair the pole has to span, such as a recess opening rather than the frame inside it. My catalogue rules pick the pole and the cut. Muse Spark Open also drafts my reply in my words, and every length in it is checked against the code's numbers. Muse Image paints the pole onto their wall. The buyer sees their size in about a minute, with a likely range and whether the pole fits anywhere in it; I get the measurement and the draft, read it and press send. Checked with a steel tape on 7 real windows, 4 of them in other people's homes: on the 5 it measured, today's code is a median 3.1 cm from the tape and never more than 5.5 cm (20 re-runs), and cut to its measurement every pole would still have fitted the width the tape measured. The tape was inside the likely range it showed on all 5. The other 2 clips weren't good enough, so it asked for a re-film instead of guessing. Three other makers I rang (a pole seller in York, a blind maker in Nottingham, a curtain maker in Frome) said they'd use it for the first enquiry; the blind maker: "Half the conversation is working out whether we're talking about inside or outside the recess." Try it on your own window: https://measure-once.vercel.app (nothing is stored). Any maker can make their own buyer link on the page. It's in use on my shop: the link https://measure-once.vercel.app/rob is in the saved reply I send any buyer who asks which size to order, and their size lands in my own inbox. The same clip also sizes a roller blind or a pair of curtains under those makers' usual rules, to show it isn't tied to my shop.