I have managed adding BI battlemap buildings to RTW. Actually what i did is compared BI and RTW descr_settlement_plan.txt files. I add all BI model descriptions to RTW file descr_settlement_plan.txt and now i can have large barbarian cities in RTW with all features and settlement looks like in BI. Castrum and Army barracks works fine.

The point is that if you create new building *.cas and want to add it to game battemap you have to desctibe it in that file. The whole battlemap is divided into sections. for example 32x32 plot. Your building must be the size of it or thare will be errors.

You have to make entries to building DataBase (descr_items.txt) file where it gets its *.cas location description.

If you don't want to add new building to your battlemap and just want to affect your settlement, then it is weri easy and works with BI v1.6

I added Odeon (theatres) to BI, these buildings are completely removed from BI

- add new description to export_descr_buildings.txt
- add new description to export_descr_buildings_enums.txt
- add new description to export_buildings.txt in text files folder

These descriptions must match or the game CTD.
in text description file must be at least two diferent descriptions the overall and the roman one (rebels faction has culture type roman).

Now you have new building in BI