Laser-cut patterns

Set the units, material, measured thickness, kerf and your laser software at the top; every tab uses them. Each tab draws a live preview (Full screen — or press F — for a closer look) and downloads SVG or DXF R12, or copies the SVG. Add to sheet collects parts for nesting.

Living hinge — choose a pattern, the row pitch (centre to centre), cut length, bridge (the material left between cuts in a row), the hinge width across the bend and the panel height. The strips between rows of cuts twist like torsion bars, and their twists add up across the hinge. The estimate takes, per link, the smaller of

The smallest inner radius is about the pitch ÷ the twist per link, and the largest bend is the twist per link × the number of links. The Bending view animates the panel bending and turns red past the estimate. Material values are indicative (birch plywood G ≈ 700 MPa, τ ≈ 8 MPa; poplar plywood 450 / 5; MDF 1000 / 2.5; acrylic 1150 / 60 with a safety factor of 4) — change them under Material properties. Rules of thumb: a pitch of about 0.5–1× the thickness, bridges at least the thickness, and longer cuts for more flex. Acrylic is brittle and notch-sensitive: laser-cut acrylic hinges crack and craze, so use them only for a gentle one-time bend, or heat-bend acrylic instead. MDF hinges snap easily. Wave hinges are estimated on their arc length, diamond and honeycomb cells use the hole width as the gap, serpentine uses the full cut overlap; spiral cells flex both ways and are not estimated.

Kerf bend — the woodworking method for bending a board with a saw: kerfs cut part-way through on the inside of the bend close up as it bends. Each kerf closes by its width k while the inside face shortens by θ·d (d = kerf depth), so you need n = θ·d ÷ k kerfs; the uncut web at radius R + d keeps its length, so they are θ·(R + d) ÷ n apart — about (R + d)·k ÷ d. Check it with a test kerf: clamp one side of a kerfed scrap and lift the free end, at a distance R from the kerf, until the kerf closes; the lift is R·k ÷ d. The template marks the kerf positions (score lines). A laser cannot cut a controlled depth reliably, so on a laser use a living hinge.

Joints

Kerf compensation — every outline grows by half the kerf and every hole and slot shrinks by half the kerf, so parts come out at their drawn size; open cuts (hinge slits) are cut on the line. The kerf test pattern itself is not compensated.

Shapes — regular polygons (sized across corners, across flats or by side), stars, and a straight-flanked gear outline with the standard addendum and dedendum. The gear is for looks and slow hand-turned mechanisms; for real involute gears use the gears tool. The tab also explains converting text to outlines before cutting.

Kerf test — cut the comb, push the pieces together and measure: kerf = piece width − measured ÷ pieces (or a square hole grows by one kerf). Use this kerf sets it for every tab.

Sheet — parts from every tab, plus plain rectangles, are packed onto sheets of the size you give (MaxRects, best short-side fit, with optional 90° rotation) with a gap between them. Material use is the parts' net area (outline minus holes) ÷ the sheet area. It packs bounding boxes, so it never overlaps but does not nest shapes into each other’s gaps — for true-shape nesting, Nest these parts sends them (with their quantities) to the sheet nesting tool.

Layer colours — cut, score and engrave go into separate SVG layers (Inkscape-style groups) with colours chosen for your software: red cut, blue score and black engrave. LightBurn makes a layer per palette colour (02 red, 01 blue, 00 black); xTool Creative Space and the Glowforge app group by colour and you choose the operation; for Epilog- or Trotec-style print drivers the strokes are 0.025 mm hairlines so they are treated as vectors. These are conventions, not standards — check the colour-to-operation mapping in your software. DXF files use layers CUT (red), SCORE (blue) and ENGRAVE, with closed polylines. Files are in the units you choose.