LaserCanvas
Preparing an SVG that actually cuts
Set the document in millimetres, convert text to paths, use hairline strokes with no fill for anything to be cut, remove duplicate and overlapping lines, and make sure every shape is a closed path. Most import surprises come from units and from strokes being treated as shapes.
Units first, because everything else depends on it
An SVG can declare its size in millimetres, pixels, points or nothing at all. If it declares nothing, the importer has to guess, and a guess of 96 dpi turns a 100 mm square into a 26 mm one. Set the document units to mm in your design tool before you start, not after.
| What the file says | What you get | Fix |
|---|---|---|
width="100mm" | Correct size | Nothing — this is what you want |
width="100" with no unit | Treated as px; roughly a quarter size | Set document units to mm and re-export |
A viewBox that disagrees with width | Uniformly scaled by the ratio | Usually intended; check one known dimension after import |
Strokes are cut lines; fills are engraved areas
A laser follows paths. A shape with a thick stroke does not cut a thick line — the stroke is a rendering instruction, and the cut follows the path underneath it. Two conventions keep this unambiguous:
- To cut or score: no fill, a thin stroke. Many people use a 0.01 mm or "hairline" stroke as a convention meaning "this is a cut".
- To engrave: a fill, and let the software raster it. A filled shape with no stroke says "remove this area".
The trap is outlined strokes. If you apply "stroke to path" or "expand stroke", a 1 mm line becomes a long thin rectangle — and the laser cuts around it, giving you two parallel cuts 1 mm apart instead of one line.
Text must become paths
An SVG referencing a font by name renders correctly only where that font is installed. Anywhere else it substitutes, and your carefully spaced sign becomes something else. Convert text to outlines before exporting — in Inkscape, Path ▸ Object to Path; in Illustrator, Type ▸ Create Outlines.
Do this on a copy, or keep the editable text on a hidden layer. Outlined text cannot be re-typed, and finding a typo after outlining means redrawing it.
Duplicates cut twice
Two shapes sharing an edge — two rectangles drawn side by side — give the laser two coincident lines. It cuts both: twice the time, a wider charred kerf, and often a part that falls out early and shifts. Design tools have a "union" or "merge" operation that removes the shared edge. Use it.
- Duplicate paths stacked exactly on top of each other are invisible on screen and double every cut.
- Open paths that look closed will not fill when engraved, and may cut as a stroke that never joins.
- Stray points left by a pen tool produce tiny zero-length moves that some controllers reject.
A short pre-export checklist
- Document units set to mm, and artboard sized to your material.
- Text converted to paths.
- Strokes thin and unexpanded; fills only where you want engraving.
- Duplicate and coincident lines merged.
- All cut shapes closed.
- Export as plain SVG rather than the editor’s own flavour, which carries metadata that importers may misread.
Common questions
Why did my SVG import at the wrong size?
Almost always units. If the file gives width and height as bare numbers, they are interpreted as pixels, and at 96 dpi a 100 mm square arrives around 26 mm. Set the document to millimetres in your design tool and export again, then verify by measuring one known dimension after import.
Should cut lines have a specific colour?
Some software maps colours to operations, so red means cut and blue means score by convention. It is a convention rather than a standard, and it varies between tools. Assigning operations by layer after import is less error-prone than relying on the importer to read your colour scheme.
Why is my text cutting as double lines?
The stroke has been expanded into an outline, so each letter stroke is now a thin closed shape and the laser cuts around both sides of it. Undo the stroke-to-path step and convert the text itself to paths instead.
Do I need to close every path?
For cutting, yes in practice — an open path leaves a tab of material and the part will not release cleanly. For engraving it matters more: a fill needs a closed boundary to know what is inside, and an open path may fill unpredictably or not at all.