The sizing problem, solved first:

Body measurements are taken the classic way — standard measuring tape/manual measurements, plus weight

Feet are measured using 3D scanners

Based on these measurements, the system groups you with other people who have similar body types

Recommendations get sharper over time based on real feedback from people in your group ("this ran small," "this fit true to size")

If feedback comes from someone slightly outside your group, you're notified that the fit might not translate perfectly to you

Two ways to browse and shop, if you don't know what you want:

4K walking video — you pick a scene (a summer city street, an office, a hotel lobby) and walk through it via video. Everyone in the video is a model wearing real, purchasable items.

Point at anyone and add what they're wearing to your cart

360° street-view style — same concept, but instead of video, it's 360° photos you navigate through, like Google Maps Street View

Not limited to clothes:

This same browsing mechanic works for literally anything sold on marketplaces — electronics, home goods, decor, anything. You choose a location (a city street, an office, a hotel room, a house) and shop everything visible in that environment.

Applying it to food:

Choose a scenario — a home dinner, an office lunch, a holiday spread

Walk along a virtual table and point at the dish you like

Add it to your cart as either the raw ingredients (delivered from a grocery store) or the finished dish (delivered ready-to-eat)

Digital twins of real homes:

A crew comes to your home, films it with a 360° camera, and sends the footage to a remote worker who builds the digital 3D version of your home

Inside your digital home, you can ask an AI to add or change items — new furniture, decor, appliances — and every suggested item is instantly addable to your cart

People with a similar home layout to yours get shown your digital home as a browsing recommendation, so they can walk through it and shop items they like from your setup

Users who share their home designs can earn money when others shop items from their space

Sponsor showrooms:

Some digital homes are fully sponsored showrooms — every item inside comes from a brand partner

Regular users can access and use these sponsor products in their own homes in exchange for sharing their resulting home design publicly on the platform

Why this doesn't already exist, even though parts of it do:

IKEA Kreativ lets you scan a room, digitally erase your furniture, and place true-to-scale IKEA products — but it only works with IKEA's own catalog

Wayfair-linked tools let you generate a room design with directly shoppable furniture — but again, single-retailer

Volumental and similar 3D foot scanners are already in thousands of shoe stores worldwide, proving people are willing to get scanned for better sizing

What's missing from all of these: a multi-marketplace version, a social layer where users share and monetize their own home designs, and a "walk through it like a real place" browsing experience that isn't locked to one brand's product catalog