> underestimating just how many different materials/fixtures/fittings get installed in a house

This is one of the reasons why I would believe Lowes or Home Depot or another construction supply place would 52 such a piece of software. They have those zillions of "something" that get installed, and the lumber. They already know what all those people buy.

At least for a construction company: pick a general house, gives you adaptations for common landscapes, choose interior finishing(s) / style(s), gives you plans (with adaptations), already has them approved for your area (with variants), gives you parts list, gives you plumbing/wiring, gives you button to put it all in your "cart," drive to store, pick up house worth of stuff, Lowes/Home Depot make a quick $50k-100k or so.

If you build a development, you say, give me 10 of that. Build it again, say I'd like my old order.

> my state doesn’t have earthquakes or hurricanes, but we do have to have stronger roofs for handling snow load. Buildings in Florida need specific methods to handle hurricane force winds. Buildings in California need specific methods to handle earthquakes.

If you tried to accomodate all of these methods now, your looking at much higher costs. But if your open source plans include all these methods, and people can produce kits that are shipped to you (either raw, or partially assembled) because they are identical, the costs would quickly start dropping..

There also seems to be shortage of cad tools avable to inspect a building plan.,like as a consumer you would home you would get a plan of the house when you buy the house

It’s also fair to say the training data is probably not readily available either

> I work in construction management and I think you’re underestimating the complexity of generating a set of construction plans that meets code, passes inspection, and has coherent aesthetics.

And yet we were able to make Figma.