To what end? Other than a sheet metal part with an extensive number of forming tool cut extrusions or a pattern of lofts and cut-lofts, what is the goal? Are trying to calculate the total weight of stair tread or platform area? Or do you want to be able to do mass properties accurately? You could model a forming tool to make the cuts, but your file sizes are going to be very large, slowing your computer quite a bit.
Mad Dog