@dc42 thanks for your answer. Are layer comments the same for every slicer? Could you answer two more questions, please: How DWC determines layer change? If I'll place any G-command (one or block of commands) with summary Z, DWC will take it, divide per layer height, then show me correct info? You wrote, that it looks for Z moves , so, it looks like "last Z" minus "pre-last Z" = "layer height" for DWC, then "last Z" / "layer height" = "layer quantity"?