To be fair it's going to be nontrivial to implement all the codes everywhere. In some cases it's going to be impossible for an app like this to judge - In the UK, for example, there are "permitted development" rights which allow certain things (like a garden office or other outbuilding) without going through a bureaucratic process. But while some of the rules are easy to automate (eg, must be less than 2.5m high) some are not. For example, the UK allows building over 50% of the garden[1]. But if it was just measurement based, you'd be able to build over 50%, then 50% of the remaining 50%, etc etc. So the rule is "50% of the original garden". That's going to be difficult for an app like this to find out.

[1] it's slightly more complicated than this

What province/state/territory in NZ? I can add it in. We just research the code compliance stuff manually so we couldn't cover the entire world but I can add your case in.

Can you link your scene? It's possible there is an edge case.

We actually do want to do more complex interior, and let you add furniture from any catalog. Can I email you on your profile about this?

Just noticed this - fixing now!