Fix #1 — Nothing appears after import

You import, LightBurn reports no error, and the workspace stays empty. Two usual suspects. First: the geometry is there but parked far away. CAD files are often drawn miles from the origin point, and LightBurn puts it exactly where the file says. Press Ctrl+A (select all) — if selection handles appear somewhere, the shapes exist; drag them back onto the work area.

Second: the geometry imported microscopically small because of a unit mismatch (more on that in fix #3). Ctrl+A, read the size in the toolbar — if your 100 mm part shows as 3.9 something, you've found it.

Fix #2 — The file won't open at all

If LightBurn refuses the file outright, it usually can't digest the DXF version or some exotic entity inside it. DXF has been revised for four decades — the newer the export format, the more unusual things it may contain. The reliable move: go back to your design app and re-export as R12 (sometimes labelled “AutoCAD R12/LT2”). R12 predates the native SPLINE entity — one of the biggest sources of import trouble — though it still allows arcs, circles, text and more, so keep the exported contents simple.

Fix #3 — It imports at the wrong size

The classic: your 100 mm part arrives at 3.937 — or at 2,540. That's not damage, it's units. A DXF frequently doesn't say whether its numbers are millimetres or inches, so LightBurn has to assume. When the assumption doesn't match the export, everything scales by 25.4× in one direction or the other.

The fix is one setting: in LightBurn, open File → Import Preferences (in newer versions, Settings → File Settings) and set the DXF import units to match what the file was drawn in. If a file keeps coming in wrong from one particular program, fix it at the source: export in millimetres, explicitly.

Fix #4 — Shapes import but won't fill

Fill mode needs closed loops, and your shapes — however closed they look — aren't. The usual culprits are contours that arrived open or in pieces — often the result of imperfect spline conversion — plus micro-gaps a few hundredths of a millimetre wide.

Run Edit → Select Open Shapes to see the guilty geometry, then Edit → Auto-Join selected shapes (Alt+J, joins endpoints within about 0.05 mm) to close what it can; Close Selected Paths With Tolerance gives finer control. If shapes stay open, the gaps need closing at the geometry level — I wrote a full walkthrough in the splines-to-polylines article.

Fix #5 — Curves arrive as thousands of tiny segments

The file imports, but selecting one curve shows a node count in the tens of thousands, the preview crawls, and on the machine the head judders around every arc. Somewhere upstream, a spline was flattened at an absurdly fine tolerance.

Re-export with a chord tolerance chosen from the accuracy your part actually needs — fine enough to be invisible on the part, coarse enough not to flood the controller; test it rather than trusting a universal number — or run the file through a cleanup pass that rebuilds the geometry at machining tolerance instead of CAD-kernel tolerance.

Fix #6 — Everything cuts twice (and edges burn)

Doubled lines are invisible on screen — two segments stacked perfectly — but the laser dutifully cuts each one, so edges char and thin parts drop out early. Sheet-metal exports are notorious for this (bend lines and duplicate contours ride along).

In LightBurn, try Edit → Delete Duplicates. It catches exact duplicates; near-duplicates offset by a hair need a geometry-level dedup, which is exactly the kind of thing an automated cleanup pass exists for.

Fix #7 — Text, dimensions, or hatches are missing

DXF text (TEXT/MTEXT entities), dimension annotations, and CAD hatch patterns aren't cutting geometry — they're instructions that depend on fonts and renderers your laser software may not have. Some arrive garbled, some not at all.

The robust habit: in your design app, convert text to outlines/curves before exporting, delete dimension and annotation layers, and if you need an engraving fill, generate it as real geometry rather than relying on a CAD hatch entity surviving the trip.

The shortcut: fix all seven at once

Every fix above is doable by hand, and for one simple file that's a fine way to spend twenty minutes. But fixes #2, #4, #5, and #6 are exactly what DXF Studio's Cleanup & Repair does in a single deterministic pass: unsupported curves converted to machine-compatible line geometry, eligible near-coincident endpoints joined within a controlled tolerance, duplicate geometry removed, units sanity-checked, and the result returned as a simplified R12 DXF that LightBurn imports cleanly. You watch the full result — including the toolpath emulation — before paying anything, so a file that can't be fixed costs you nothing.

What DXF version does LightBurn import most reliably?

R12 with plain LINE and POLYLINE geometry is the most predictable. R12 predates the native SPLINE entity; keep the contents to simple geometry, since the format itself still allows arcs, circles and text.

Why did my DXF import 25.4 times too big or too small?

Unit mismatch. The file was drawn in millimetres but imported as inches, or the reverse. Set LightBurn's DXF import units to match the file, or re-export explicitly in millimetres.

Why does LightBurn show an empty screen after importing my DXF?

Usually the geometry is either parked far from the drawing origin or imported microscopically small due to a unit mismatch. Select All — if handles appear, move the shapes back onto the work area.

Why does my laser cut every line twice?

The file contains duplicate geometry — two identical lines stacked on top of each other, common in sheet-metal exports. Use LightBurn's Delete Duplicates, or a geometry-level cleanup for near-duplicates.

Does LightBurn import text from a DXF?

Not reliably — DXF text depends on fonts LightBurn may not have. Convert text to outlines or curves in your design app before exporting, so it arrives as plain geometry.