Hi Garden Baker
All that’s is required to cut a royal iced cake is a sharp knife (the royal icing has glycerin added which stops the royal icing drying rock solid so no need for a hammer/chisel), as to all of the piping most of that will just break away from the cake during the cutting process.
Hopefully this picture will help re the pre cut portion https://pic.cakesdecor.com/o/Wedding_cake_12_fwgn4o.jpg!
