kerfscript

Coming from OpenSCAD

KerfScript borrows OpenSCAD's syntax on purpose: if you have written OpenSCAD, you can read KerfScript and write it within minutes. It is not a drop-in replacement. It only makes flat parts, and a few rules are different. OpenSCAD files do not run unchanged.

The same

  • Statements, modules, functions, for, if, let, each, list comprehensions, ranges like [0:2:10], function literals.
  • children(), children(i) and $children.
  • Special variables that start with $ are dynamically scoped, and $fn, $fa and $fs set curve resolution.
  • 2D shapes: square() (also called rect()), circle(r) or circle(d =), polygon(points, paths), text().
  • Transforms: translate, rotate, scale, mirror, multmatrix.
  • Combining: union, difference, intersection, hull, offset(r), offset(delta, chamfer).
  • echo(), assert(), use <...> and include <...>.
  • Customizer comments: // [40:5:400], /* [Group] */, /* [Hidden] */, and captions on the line above. Tools that read OpenSCAD settings read these.

Different

OpenSCAD KerfScript
Output a solid, as STL, 3MF and more a cut file, as SVG or DXF
Dimensions 3D, and 2D for export 2D only
Assignments the last one in a scope wins everywhere in it run in order; a later one takes effect from that line
Errors many mistakes give undef and a warning type mistakes stop the program, naming the line
color() colours a shape not available; use cut(), score(), engrave() or layer()
Fonts system fonts only fonts you pass in, so a file renders the same everywhere
Libraries any file on disk the standard library and whatever the host allows

Not in KerfScript

3D modules (cube, sphere, cylinder, polyhedron, linear_extrude, rotate_extrude, projection), minkowski, resize, color, import, surface and render. Each stops with an error that names it, so you find out at once.

Only in KerfScript

  • Layers: cut(), score(), engrave(), guide() and layer(). See Layers.
  • Kerf compensation with $kerf. See Kerf.
  • Parts, quantities, materials and sheet packing: part(), material(), $sheet, $gap. See Parts and sheets.
  • Joinery that reads $thickness: finger_rect, finger_holes, tslot, living_hinge.
  • Lines as well as areas: line(), polyline(), arc(), path(), stroke() and outline().
  • Shapes OpenSCAD lacks: ellipse, regular_polygon, star, rounded rect(r =).
  • text_width() and text_metrics(), to size a part to its text.

Porting a 2D design

  1. Drop linear_extrude() and any 3D parts.
  2. Replace color() with the layer the shape belongs on.
  3. Check assignments: code that relied on a later assignment overriding an earlier one should assign once.
  4. Pass the fonts your text() calls use.
  5. Add $kerf and $thickness, and replace hand-made finger joints with finger_rect() if you want them to follow the material.