How it works
Each part is laid out with its length along the sheet's length, unless turning it saves board and the grain doesn't matter. Every cut runs right across the piece it divides, as on a panel saw, table saw or track saw, so nothing in a layout needs a plunge cut or a stopped cut.
The saw cut is taken out between every pair of parts, and the trim from every edge of the sheet first. Many orders and ways of fitting the parts are tried, and the layout with the fewest sheets wins. Between layouts with the same number of sheets, the one with fewer parts turned, then the bigger offcut left over, is kept.
For how many sheets a job needs before you've drawn it, see how many sheets of MDF do I need, and for why the saw cut matters, saw kerf and sheet layouts.
Questions
How does it lay the parts out?
Every cut runs from one edge of a piece to the other, as on a table saw, panel saw or track saw, so every layout can be cut as drawn. It tries many orders and ways of fitting the parts and keeps the layout with the fewest sheets, then the fewest parts turned, then the biggest offcut left over.
What should I put for the saw cut?
The width of your blade's cut (the kerf): about 3 mm for most panel saw and track saw blades, a little more for a thick table saw blade. It's taken out between every pair of parts, so a wrong figure can mean a part that doesn't fit at the end of a row.
What is the trim for?
The edges of a sheet are often knocked or chipped. A trim takes that much off every edge before anything is laid out. Leave it at 0 if your sheets have clean edges.
When should I keep the grain?
For veneered boards, oak-faced plywood and woodgrain melamine, where the parts should all run the same way: then no part is turned. MDF and plain plywood can be turned, which often saves a sheet. Length is always the way along the grain.
Is this the same as JoinerKit's cutting list?
Yes. It's the same code that lays out the sheets in JoinerKit, where the parts come from the units you draw instead of being typed.