What the “code” shape does
Draw → QR code and barcode creates a code as an ordinary shape: move it, rotate it, resize it and engrave it like any area (milling: shallow pocket or V-carving, laser: fill). The code is generated inside the app, without internet and without any outside service.
| Type | For | Content |
|---|---|---|
| QR code | links, text, serial numbers; phones read it with the camera | any text |
| Data Matrix | very small codes on rating plates, metal and plastic | any text |
| Code 128 | barcode for article and serial numbers | letters, digits, punctuation without accents |
| EAN-13 | retail article numbers | 12 digits (check digit is added) or 13 digits |
Content and placeholders
The content may use the placeholders of the variable text, for example https://example.com/device/{nr} or SN-{nr:5}. The chips below the field insert them at the cursor, including the columns of a pasted list. The code always shows the current row; when the row changes and in a series every part gets its own code.
If a row gives no valid code (for example letters in an EAN), the previous code stays and a message names the shape.
Size, quiet zone and error correction
- Edge length or width: size of the code without quiet zone. Afterwards you can scale it like any shape with the handles or via width and height; barcodes also in height only.
- Quiet zone: free margin around the code in modules. Required are 4 for QR codes, 1 for Data Matrix, 10 for Code 128 and 11 for EAN-13. Do not engrave anything in this margin.
- Error correction (QR only): L, M, Q or H; up to about 7, 15, 25 or 30 % of the code may be missing. Higher levels need more modules. M fits almost always, use Q for rough surfaces and burn marks.
The preview shows the code with its quiet zone (dashed), the overall size and the size of one module.
Human-readable text below barcodes
For Code 128 and EAN-13, Human-readable text below (in the window and in the properties) places the readable content as a separate text shape under the bars: EAN-13 in three groups as in retail (“4 006381 333931”, with check digit), Code 128 its content. The font is a clear sans serif with a little letter spacing, similar to OCR-B, about seven modules high and never wider than the code. The text follows the code: when you change the content, size or quiet zone, or the row of the variable text changes, it is set again and placed under the code. It sits on the code’s layer and is engraved like it. To move them, select both (they are selected right after inserting). The app remembers the choice for new barcodes.
Milling and lasering
A module is the smallest square or the narrowest bar. For a readable code the tool has to fit into it:
- Milling: the bit must be narrower than a module, otherwise modules are left standing. For fine codes V-carving with a pointed V-bit works well. The properties warn when the tool of the layer is too wide.
- Laser: a module should be at least two beam spots wide. One pass with a small line interval gives the best contrast.
- Phones read codes reliably from about 0.4 mm per module; more is better.
If the modules are too fine for the tool, the toolpath calculation reports it once per code (not for every module) and suggests what helps: a smaller bit from the project that fits into a module, or a profile with a finer beam spot, or the width from which the code comes out cleanly with the current tool.
Merge modules (default) turns neighbouring modules into one area: fewer paths, a calmer engraving. Switched off, every module is a square of its own.
Light on dark (inverted) engraves the quiet zone and the light modules and leaves the dark ones. You need this when the engraving turns light: slate, anodised aluminium, dark painted parts.
Editing
With a code selected, the properties show type, content (applied when you leave the field or with Ctrl+Enter), error correction, quiet zone and the switches. Edit in window … opens the large preview. Editing the points of a code with the node tool turns it into an ordinary path that no longer updates from its content.
Sign wizard
On request the sign wizard places a QR code or Data Matrix to the right of the text or a barcode below it, on its own layer Code before cutting out. Placeholders such as {nr} work here too.