kerfscript

Parts and sheets

A design often has more than one piece. KerfScript lets you name each piece, say how many you need and what it is cut from, and lays them out on sheets.

Parts

part("side", qty = 2) rect([100, 60]);
part("base") rect([100, 100]);

part(name, qty = 1) makes a named part. Everything inside it is one piece with its own layers. Shapes outside any part form one part called part.

Parts show up in the part list with their size and cut length, which the playground and kerf check print.

Materials

Each part records $thickness, $kerf and $material where it is made. material() sets all three for the parts inside it:

material(thickness = 3, kerf = 0.15, name = "plywood") {
  part("front") rect([100, 60]);
  part("back") rect([100, 60]);
}
material(thickness = 2, kerf = 0.1, name = "acrylic") {
  part("window") rect([80, 40]);
}

Sheets

With the default $layout = "pack", KerfScript:

  1. groups parts by material and thickness,
  2. copies each part qty times,
  3. turns a part 90° when that makes it fit,
  4. packs them in rows onto sheets of $sheet (600 by 400 mm by default), with $gap millimetres between parts and around the edge.

A part bigger than the sheet gives a warning. With $layout = "none" parts stay where your program put them.

$sheet = [300, 200];
$gap = 4;

One file per sheet

The design above makes two sheets: one of plywood and one of acrylic. The combined SVG shows every sheet stacked one above the other, which is useful for a preview but is not a cutting job: the sheets are different materials.

Cut each sheet as its own job:

  • On the command line, --split writes one file per sheet (design-1.svg, design-2.svg, ...). kerf check lists the sheets with their material and thickness.
  • From JavaScript, result.sheets has an SVG and a DXF for each sheet, with its material and thickness.

Before cutting, check that each file's material and thickness match the sheet in your machine.