LightBurn Import SVG: Step-by-Step Guide for Laser Files

You downloaded a design, opened LightBurn, and now there is a pile of lines on the screen and a layers list you did not ask for. This guide walks through the LightBurn import SVG process from start to finish: getting the file in, checking the size, matching colours to cut, engrave and score, and the small fixes that stop a ruined sheet.

Open or import: which one to use

LightBurn has two ways to bring a file in, and they behave differently.

• File > Import (Ctrl+I on Windows and Linux, Cmd+I on a Mac) adds the drawing to your current project. Use this for SVG, DXF, AI, PDF and EPS files, and for images.
• File > Open loads a complete LightBurn project (.lbrn or .lbrn2), including its layers and cut settings.

Dragging a file onto the workspace does the same as Import. One catch: if you import an .lbrn2 file instead of opening it, only the shapes come in and the layer settings are left behind.

LightBurn import SVG: step by step

Here is the routine that works for almost any SVG laser file.

1. Start a new project (File > New) so nothing from the last job gets mixed in.
2. Press Ctrl+I (Cmd+I), pick the SVG, and click Open.
3. With everything still selected, look at the width and height boxes in the top toolbar. Compare them with the size the designer lists. If the file came with a dimensions guide, use that.
4. Open the Cuts / Layers window. You should see one layer per colour in the file.
5. Double-click each layer to open the Cut Settings Editor and set the mode, speed and power.
6. Turn off output for any layer that should not be lasered, such as labels or reference lines.
7. Click Preview (Alt+P) and watch the simulated job before sending anything to the machine.
8. Run Frame to check the job fits on your material, then Start.

Check the size before anything else

A wrong size is the most common SVG import problem, because design programs store SVG units in slightly different ways. When the size is off, it is usually off by a recognisable ratio:

• About 75% or 133% of the expected size often means a 72 vs 96 DPI mix-up.
• About 4% or 25 times the expected size usually means inches and millimetres were mixed up.

To fix it, lock the aspect ratio (the padlock icon next to the width and height boxes) and type the correct width. Then measure a known feature, such as a slot that should equal your material thickness. If the slots measure right, the rest of the drawing will be right too.

A 2% error on a 300 mm box panel is 6 mm, enough to stop it closing. If you keep fighting the SVG size, try the DXF version, which tends to keep scale more reliably. Our SVG vs DXF comparison explains why.

How colours become layers

LightBurn sorts imported shapes into layers by colour. Each layer has its own settings, so the colour of a line decides what the laser does with it.

A common convention, and the one used in files from our laser cut file generator, looks like this:

• Red (#FF0000) for cut lines. Set this layer to Line mode with cutting power.
• Blue (#0000FF) for engraving. These are filled shapes, so set the layer to Fill mode.
• Green (#00FF00) for score lines. Line mode with low power, so the laser marks the surface without going through.
• Black for reference, such as part names. Switch the Output toggle off for this layer.

LightBurn matches each colour to the nearest colour in its own palette, so swatches may look a shade different. That is normal. What matters is that red, blue and green each land on their own layer. New to the three operations? See laser cutting vs engraving vs scoring.

Setting up cut, engrave and score layers

Double-click a layer in the Cuts / Layers window to open the Cut Settings Editor. The key fields are Mode, Speed, Max Power and Number of Passes.

Treat any numbers as starting points to test on scrap, because every machine behaves differently. As a rough guide for a 40 to 60 W CO2 laser on 3 mm plywood:

• Cut: slow speed and high power, then adjust until it cuts cleanly through in one or two passes.
• Score: a fast speed and a low power, perhaps 10 to 20% of what you cut with, until you get a clean visible line.
• Engrave: a fast speed and moderate power, with the line interval set to around 0.1 mm to start.

Diode lasers need much slower speeds and often several passes. Write down the settings that work.

Cut order: inside first, outside last

If the outline is cut before the inner holes, the part can drop or shift and the holes land in the wrong place. Open Optimization Settings (in the Laser window), tick Cut inner shapes first, and use Order by layer so engraving and scoring run before cutting.

Cleaning up the drawing

LightBurn's Edit menu fixes the usual SVG faults:

• Select Open Shapes finds lines that are not closed. Fill engraving needs closed shapes.
• Auto-Join Selected Shapes joins segments whose ends touch, such as an outline made of many pieces.
• Delete Duplicates removes stacked lines that would otherwise be cut twice, widening and scorching the edge.
• Close Selected Paths closes shapes whose ends nearly meet.

LightBurn also cannot read fonts embedded in a file, so convert text to paths before export.

Kerf: do not double count it

Kerf is the width the beam burns away. The Kerf Offset setting in the Cut Settings Editor moves the cut line to make up for it, but if your design already allows for kerf, leave it at zero. Files from our laser cut tool build kerf into the joints, using starting values such as 0.15 mm for 3 mm plywood and MDF and 0.12 mm for cast acrylic. Adding LightBurn's offset on top would make the joints too tight. If you are unsure of your own machine's kerf, our kerf test guide shows how to measure it in ten minutes.

Common import problems and fixes

• Everything landed on one layer. The SVG used a single colour, or colours were set on groups rather than the shapes themselves. Ungroup (Ctrl+U), then select each set of lines and click a layer colour to move it.
• Engraving comes out as outlines only. The layer is in Line mode, or the shapes are not closed. Switch to Fill mode and check for open shapes.
• Lines cut twice. Run Delete Duplicates.
• Job is in the wrong place on the bed. Check the Start From setting in the Laser window. Absolute Coords uses the position in the workspace; Current Position and User Origin place the job relative to the laser head.
• Some parts are missing. They may sit in a clipping mask or hidden layer. Re-save the SVG with all layers visible.

Before every real job, stay at the machine, keep the lid closed, run your extraction, and have a fire extinguisher close by. Never leave a laser running unattended, even for a minute.

Frequently asked questions

Why is my SVG the wrong size in LightBurn?

The file stores units differently from what LightBurn expects. Lock the aspect ratio, type the correct width, and check a known measurement. If it keeps happening, use the DXF version.

Should I open the .lbrn2 file or import the SVG?

Open the .lbrn2 with File > Open to keep its layer setup, then adjust speed and power for your machine. Import the SVG when adding the design to a project you already have open.

Can LightBurn import SVG files from Inkscape and Illustrator?

Yes. Both work well. Save as a plain or standard SVG, convert text to paths, and check the size after import.

How do I stop LightBurn cutting reference text?

Put the reference text on its own layer and switch that layer's Output toggle off in the Cuts / Layers window. It stays visible on screen but the laser skips it.