Lot -->
extrude ( world.y, buildingHeight )
Building.
after the extrusion, you need to decide if you split the volume into (again volumetric) floors or first do a comp(f) to split off each facade side, which you then can split into floors.
there are different possible strategies, so I'd first play around a little.
Normally I do it this way, but this time I dont work with the building footprints but with the parcels and I perceived the following problem of non-horizontal extrusion (I need horizontal roofs)
I tried lots of things (like the following code and different combinations of its components) without satisfying solution: