Custom quotation divided by sections - use case for nested/child tables?

I have this use case - I need to create Configuration (quotation) of electrical equipement for a building. There are rooms in the building, and there is a lot of different equipement in each room (lights, sockets, switches, sensors etc).
I have created Doctype called Configuration, what keeps basic info of the building (name, address, customer etc). Then I have Doctypes Room and Room Item (child table) what represents different Rooms (these rooms are unique for every building). Equipement of the rooms is represented by standard Item.

With all of this I need to create configuration (quotation) of electrical equipement for the building, separated by rooms. Ideal solution is to have one table, where I add a room, and into this record I add all the equipement and so on.

Is there a way how to solve this without nested tables, what I understand as a bad practice as described for example here?

maybe this app can give you some idea?
not production ready though.

Hi @szufisher, thank you for your reply. I have already seen your app, for configurable items like PCs or some similar way assembled products it is an excellent idea.
If I understand it correctly, super BOM in terms of your app would be a Room in my use case. Maybe I am missing something, but I think I need one more level, what is the building - do I have to create one more super-super BOM, what will contain all the super BOMs (Rooms)for the building?

I have tried to test it, but I got stuck at creating super BOM - in add Item dialog I get “Not permitted” message after clicking on any field in Configuration section.

How does look such BOM in Quotation, is it possible to print it with all the sub-sub-Items by Rooms and give the customer overview, what is in every Room (sub BOMs)?

For your use case, the building object can be at the quotation/order level, while multi configurable items( Rooms ) can be mapped to quotation / order items.

Yes, you are right, it could be as you say. But it is also important to get an understandable output for the customer in the form of an offer.
I’d like to try it, don’t you have an idea why I’m getting that error message? I didn’t see it until I installed your app…

Hi @szufisher,
I have tried to install it to several instances of erpnext, including fresh installation, and still getting that “Not permitted” message after clicking on any field in Configuration section of BOMs item and thus I am not able to enter anything there. Any idea what could be wrong?

Btw what is the current state of the app? I saw that the last commit on git was made in March.