CGAL's docs are pretty good but there's a fair amount they assume you're know. I bought a copy of CGAL Arrangements and Their Applications and found it to be very helpful for filling in those gaps and understanding the architecture.
With a better understanding of arrangements, I started trying to implement the OBB-based Subdivision algorithm described in Procedural Generation of Parcels in Urban Modeling. It's looking promising but I still need to implement the checks that a lot's area is within a range and that it has a certain amount of street access.
- Separated the models and views so now buildings that share a BuildingPlan are drawn as instances.
- Added a concept of a District which has a ZoningPlan that determines how it is divided into Blocks and Lots and which BuildingPlans are used.