LightBurn Projects

LightBurn runs most CO₂, diode and fibre lasers (GRBL, Ruida, Trocen, TopWisdom, EZCad and others). File › Export › Export… writes the drawing as a LightBurn project (.lbrn2) that opens ready to run: each of the drawing's layers on a LightBurn layer of its own, set to cut, score or engrave, at the speed, power and passes you choose. Choose LightBurn Projects as the file type in the export dialog (or type a name ending .lbrn2).

What is written

A LightBurn layer for each layer that has something to cut: each is a LightBurn cut setting with its number (00 to 29, in that layer's colour in LightBurn), its name (the drawing layer's), its speed, its most and least power, its passes and its mode: Line for cuts and scores, Fill for engraving (with its line interval, scanning both ways).
The lines as LightBurn shapes, in millimetres: a circle as an ellipse; everything else as a path of lines and Béziers. Arcs become Béziers of at most a quarter turn each, within 0.03 % of their radius; other curves become Béziers within the curve tolerance (0.01 mm unless you change it). Text is written as its outlines.
The order: engraving first, then scoring, then cutting, so parts are cut free last. LightBurn's own optimisation (Cut inner shapes first and so on) orders the shapes within each.
Where: the drawing's lower left corner at 0,0, LightBurn's origin, unless you switch off Move to the origin.
What every export leaves out is left out here too: hidden elements, the Construction layer, layers that aren't plotted, the Tape layer, and the Dimension layer.

The export options

After you choose the file, the options list each layer the drawing has lines on:

Option	What it does
Operation	Cut through the lines, Score them (a light line on the surface), Engrave (fill) the shapes they close, or Leave out the layer.
LightBurn layer	The LightBurn layer (00 to 29) it goes on, and so its colour in LightBurn. Two drawing layers put on one LightBurn layer are run with the first one's settings (the messages say so).
Speed	How fast the head moves with the beam on, in mm/s.
Most power, Least power	The power at full speed, and at corners where the head slows down, in per cent.
Passes	How many times the layer is run.
Line interval	Engraving: the distance between the lines the shapes are filled with.

Each layer starts from what it is:

Layer	Operation	Speed, power
Cut, Partial Cut, Perforation, Cut-Crease, and layers with other names	Cut	20 mm/s, 50–60 %
Crease, Reverse Crease, V-Cut, and layers named Score, Mark, Scribe	Score	100 mm/s, 15–20 %
The standard Engrave and Etch layers (where the library's laser designs put the lettering, borders and grooves to engrave), and layers named Engrave, Etch, Raster, Fill	Engrave	300 mm/s, 20–25 %, lines 0.1 mm apart
Dimension, Tape, and layers that aren't plotted (Print, Form, Window film)	Left out

A layer's own machining settings (Production › Tool Options) come first: its Feed rate gives the speed (converted from the drawing's units a minute to mm/s), and its Depth and Step down the number of passes. Your choices are remembered for the next export, layer by layer; Reset to Defaults puts them back. The LightBurn layer colours are the ones LightBurn shows, so the drawing's black Cut layer goes on 00 (black) and the red Crease layer on 02 (red).

On the laser

Open the project in LightBurn (File › Open). The layers appear in the Cuts / Layers window with their speeds, powers and passes; check them against your material before you run, as every laser and material differs.
Set Start From to Absolute Coords to cut where the drawing is placed (from the origin, with Move to the origin on), or to Current Position or User Origin to cut wherever you put the head.
Use Frame to check the job fits the sheet, then Start.

A layer's kerf offset, air assist, Z offset and LightBurn's other settings are set in LightBurn: keep the settings that suit each of your materials in LightBurn's Material Library and assign them to the layers there.

About the format

LightBurn's project format is XML, and LightBurn Software has not published a specification for it. The export writes the part of it that LightBurn's own projects use and its developers have described: the project root, a cut setting for each layer, and Path and Ellipse shapes whose vertex and primitive lists hold lines and Béziers. Anything else (a material height, a rotary, images, variable text) is left for you to set in LightBurn.

To estimate how long a job takes and what it costs, use the Laser job time and cost report.