pascalorg/editor ? reverse-engineered prompt

Build me a 3D architectural editor for the web. It's for creating and sharing building designs, kind of like a simplified CAD tool.

The core idea is a user can open a blank 3D space and start building a house. They should be able to create an overall site, add a building, and then add multiple levels or floors to it. On each floor, they'll draw walls, slabs, and ceilings. When they add an item like a door or window to a wall, the app should automatically cut out the hole for it.

A key feature is how users view the model. Besides seeing the whole building, there needs to be an 'exploded' view that separates the floors vertically for a better look, and a 'solo' mode to isolate and edit a single floor at a time. The whole thing should be highly interactive, rendered with React Three Fiber. Of course, it also needs standard features like undo/redo and the ability to save progress in the browser.