Layers
Every shape belongs to a layer, and each layer has a colour from LightBurn's palette: 30 numbered colours, C00 to C29, plus two tool layers, T1 and T2. The colours don't show what the finished piece looks like. They only separate jobs: a common habit is red for cuts and black for engraving, but designers choose freely. The layer name, when the designer set one, is often the most useful hint, such as "Cut 3 mm birch".
Modes
- Line follows the path of each shape. Strong and slow cuts through; light and fast scores a line.
- Fill sweeps back and forth inside closed shapes, row by row, to engrave an area. Overlapping shapes on the same layer cancel out, which is how letters keep their holes.
- Offset fill engraves an area with lines that follow the outline inwards, which suits hollow shapes.
- Image engraves a picture, usually dithered into dots.
- Tool layers never burn. They hold the material outline, alignment guides and other helpers.
Speed
LightBurn shows speed in mm/s or mm/min, depending on the user's preference, but the file always stores millimetres per second. A layer stored as 16.6667 was set as 1,000 mm/min. This page shows both.
Power
Power is a percentage of the laser's maximum. Max power is the level the laser reaches at full speed. Min power only matters for some controllers (LightBurn's documentation names DSP lasers) and for greyscale images, where it is the power used at slow speeds and in corners. Remember the percentage belongs to the designer's laser. The same number on a different machine gives a different result.
Passes, interval and angle
Passes is how many times the layer repeats. Line interval is the gap between rows on Fill and Image layers. 0.1 mm is the same as 254 lines per inch, because DPI is 25.4 divided by the interval. Scan angle turns the rows, and cross-hatch adds a second set at right angles.
Values that aren't in the file
To keep files small, a .lbrn2 leaves out values that equal LightBurn's defaults. LightBurn's documentation gives its universal defaults as 100 mm/s, 20% power and a 0.1 mm line interval, and a missing pass count means one pass. This page shows those values in grey italics so you can tell them from values the designer set. If the designer changed their own defaults, the real value may differ.
Run order and output
Layers run in the order shown in LightBurn's Cuts / Layers list, which the file stores as a priority. A layer can also have its output switched off. It stays in the file but won't burn, and this page marks it.
Pictures, notes and a preview
Images are stored inside the file, so a project is self-contained. Each image can also carry the path of the original picture on the designer's computer, such as a folder and file name. That's worth knowing before you share a project, and this page shows it. LightBurn also saves a small preview of the design and any project notes.
What it doesn't contain
No machine profile, no lens or focus height, and no material thickness you can rely on. Fonts aren't included either. Text normally carries a saved outline, but if it doesn't, the shape depends on fonts installed on the computer that opens it.