BetaBetaAdds a slab: an outline in a storey's plan, with optional holes, its top topOffset above the
storey's floor and its thickness below that.
The slab is made of the named layerSet, first layer at the top, or of one layer thickness
thick. Outlines may wind either way.
The model, the storey, the outline and holes, the thickness or layer set, and the slab's kind
A new model with the slab
Slabs: floors, roofs and landings, each an outline in a storey's plan with optional holes, extruded down from its top by its thickness or by the layer set it is made of.