kerfscript

Layers

Every shape in KerfScript is on a layer, and the layer decides what the laser does with it. Shapes that are not wrapped in a layer module are on cut.

The built-in layers

Layer Wrap shapes in Colour in the file What the laser does
engrave engrave() black #000000 engraves the area of the shapes
score score() blue #0000ff marks lines and outlines without cutting through
cut cut() red #ff0000 cuts the outlines through, with kerf compensation
guide guide() light blue nothing; shown only when you ask for guide lines 
difference() {
  circle(d = 90);
  circle(d = 6);
}
engrave() difference() { circle(d = 74); circle(d = 68); }
score() circle(d = 84);

# and % in front of a module call move it to the guide layer, which is handy for checking where something is without cutting it.

Areas and lines

Layers hold two kinds of geometry:

  • Areas come from shapes like rect(), circle() and text(). On engrave the area is filled; on cut and score its outline is followed.
  • Lines come from line(), polyline(), arc() and living_hinge(). They are followed as they are, on any layer. On cut they are cut through, which is how a living hinge is made.

stroke(width) turns lines into areas, for engraving a line of a given width. outline() turns areas into their outline lines.

The material

When a part is finished, KerfScript takes the union of everything on the cut layer as the material. Then:

  • engraving and scoring are clipped to the material, so nothing is marked inside a hole or off the part;
  • cut lines are clipped to the material too;
  • if the material falls apart into separate pieces, you get a warning, because that usually means a missing bridge.

Your own layers

layer(name, mode, color) makes a layer of your own, for example a second engraving pass at a different power:

rect([60, 40]);
layer("deep", mode = "fill", color = "#00aa00") translate([10, 10]) rect([20, 20]);
engrave() translate([40, 20]) circle(d = 12);

Modes are "cut", "line" (score), "fill" (engrave) and "guide".

Order in the file

Layers are written in this order: engrave, your own layers, score, cut, guide. Within the cut layer, holes and inner cuts come before outer outlines, so a part does not drop out before its holes are cut.

That order is a good default, but it does not control your machine. Most laser software sorts and orders operations itself. Check the cut order, and set power, speed and passes for each layer, in your laser software before you run the job.