Hi ! I'm working on a british world, I'm on the thinking and sketchy phase to prepare my project and some questions poped in my head.

I was wondering if I could add custom shell like university (dormitory, class) or late night (appartment, bar...) where I could build inside with a unique architecture outside I think that my skill in blender are good enought to make simple shell, I did see people do decorative shell but is it possible to make custom shell where you sims can enter as community/residential lots ?