SLF Tracer: Convert Any Font to Single-Line
The SLF Tracer is a Pro feature that automatically converts any TTF or OTF font into a single-line SLF font for laser engravers and pen plotters. It uses a contour midpoint algorithm that finds the centreline of each filled letterform and fits smooth bezier curves through it. The result needs human review — some glyphs come out perfect, others need minor node editing — but it eliminates the tedious manual work of tracing individual letters from scratch.
What fonts work well
The Tracer works best on fonts with consistent stroke weight — regular weight sans-serif fonts, monoline scripts, and geometric typefaces. Bold fonts, display fonts with extreme thick-thin contrast (like Bodoni or Didot), and fonts with complex overlapping strokes are harder to trace cleanly and require more review. Avoid fonts with decorative fills, gradients, or multiple layered contours. The Tracer extracts the mathematical centreline of each stroke, so the cleaner and more consistent the original font geometry, the better the result.
Step 1 — Upload a font file
Go to pathhaus.com/create/tracer. Drag a TTF, OTF, or WOFF file onto the upload zone, or click to select from your file system. The Tracer reads the font metadata and shows the family name and glyph count. You do not need a license to trace a font for personal or internal use, but commercial redistribution of a traced font derived from a copyrighted original may infringe the original font license. When in doubt, use open-source fonts (OFL-licensed fonts from Google Fonts are safe).
Step 2 — Configure the trace
Select the character ranges to trace: uppercase, lowercase, digits, punctuation, and space. For a quick test, start with uppercase only — it is faster and gives you a representative sample of the quality. Choose a quality setting. Fast uses fewer sample points per curve and runs in seconds. Standard is the recommended default. Precise uses more sample points and produces smoother curves on complex glyphs, but takes longer. Click Start Tracing.
Step 3 — Review the glyph grid
After tracing, a grid shows every glyph with a quality badge. Green (pass) means the node count is within range and the path looks clean. Yellow (review) means the glyph has a high node count or the algorithm flagged a potential issue. Red (failed) means no usable path was extracted — this happens with space characters, glyphs with very complex geometry, or missing glyphs in the source font. Failed glyphs are excluded from the font automatically. Start by checking all yellow badges first — they usually need just a few node deletions to clean up.
Step 4 — Edit glyphs in the path editor
Click any glyph to open the path editor. The extracted bezier path is rendered in the preview pane. Drag nodes to adjust their position. Click a node and press Delete to remove it. Use the Undo button (or Cmd/Ctrl+Z) to reverse your last change. The node count updates live — aim to get complex glyphs below 30 nodes for optimal machine performance. For a letter with a completely broken trace, the easiest fix is to click the glyph, clear the path, and redraw it from scratch using the node editor.
Step 5 — Download or publish
When you are satisfied with the glyph set, enter a name for the font and optional style tags in the Publish panel on the right. Click Download OTF to get an installable font file you can use immediately in LightBurn, Inkscape, or any app. Click Download JSON to get the Pathhaus SLF bundle for re-import or sharing. Click Save to Library to publish the font to your Pathhaus account — it will appear in your creator dashboard, in the Studio font picker, and can be optionally listed on the marketplace.
Quality benchmarks to aim for
A well-traced font has an average of 10–25 nodes per glyph. Above 40 nodes per glyph is a sign the trace needs cleanup. The Node Counter tool (free, no login required) can help you measure the quality of an exported SVG. For laser engraving, the Travel Optimizer in the Studio can further reduce machine head movement after the font is created — trace quality and travel optimization work together.
Try it in Pathhaus Studio
Free to start — optimize and export your first font file in under 5 minutes.