When you're ready to cut a design on your CNC plasma table, the file format you start with matters more than you might expect. The two most common vector formats in the plasma cutting world are DXF (Drawing Exchange Format) and SVG (Scalable Vector Graphics). Both can describe the same shapes, but they handle units, arcs, layers, and metadata very differently — and those differences affect your CAM workflow.
What is DXF?
DXF was created by Autodesk in 1982 as an interchange format for AutoCAD. It became the de facto standard for sharing 2D engineering drawings across CAD programs. Nearly every professional CAD application — AutoCAD, Fusion 360, SolidWorks, FreeCAD, LibreCAD — can export DXF files.
DXF files store geometry as discrete entities: lines, arcs, circles, polylines, splines, and text. Each entity can belong to a named layer, carry color properties, and include precise dimensional data. The format supports both imperial and metric units, though the unit handling is one of its biggest sources of confusion — a DXF file may or may not declare its units explicitly, and different CAD programs handle this inconsistently.
What is SVG?
SVG is a W3C web standard, first published in 2001. It was designed for displaying scalable graphics in web browsers, not for engineering or manufacturing. Programs like Inkscape, Adobe Illustrator, and Figma use SVG as a native or primary export format, and SVG files are the standard for web graphics, logos, and icon design.
SVG files use XML markup to describe paths, shapes, text, and groups. Paths are defined using a compact command syntax (M for move, L for line, C for cubic bezier, A for arc). SVG supports CSS styling, gradients, filters, and animations — none of which are relevant for plasma cutting, but which can create cleanup headaches when importing design files into CAM software.
Key Differences for Plasma Cutting
| Feature | DXF | SVG |
|---|---|---|
| Origin | CAD/engineering (Autodesk) | Web graphics (W3C) |
| Units | Can be inches, mm, or unspecified | User units (usually px, mm) |
| Arcs | True arc entities | Arc commands or bezier approximations |
| Layers | Full layer system with names/colors | Groups only (no true layers) |
| Precision | High (engineering-grade coordinates) | High (floating point, but varies by source) |
| File size | Larger (verbose format) | Smaller (compact path syntax) |
| Styling data | Minimal (colors, line types) | Can include fills, gradients, effects |
| Typical source | AutoCAD, Fusion 360, SolidWorks | Inkscape, Illustrator, web downloads |
When to Use DXF
Use DXF when your design comes from a CAD program. If you drew your part in AutoCAD, Fusion 360, SolidWorks, FreeCAD, or any engineering CAD tool, export as DXF. The format preserves the exact geometry — true arcs, precise coordinates, layer organization — that your CAM software needs.
DXF is also the better choice when dimensional accuracy is critical. If you're cutting parts that need to fit together, mate with existing hardware, or match a technical drawing, DXF carries the engineering intent more faithfully than SVG.
The main headache with DXF is unit ambiguity. A file exported from one CAD program in millimeters may import at the wrong scale in another program that assumes inches. Always check the dimensions of your imported geometry before generating toolpaths. CutArc's DXF importer handles the most common unit scenarios automatically, but a quick sanity check is always wise.
When to Use SVG
Use SVG when your design comes from a graphic design tool or the web. If you created artwork in Inkscape, downloaded a design from an online marketplace, or received a logo from a graphic designer, it's almost certainly an SVG.
SVG is the practical choice for sign cutting and decorative work. Most free CNC design files available online are distributed as SVGs. Inkscape — the most popular free vector editor — uses SVG as its native format. If your workflow involves designing text, logos, or artistic shapes, SVG is likely your starting point.
The challenge with SVG files for plasma cutting is cleanup. SVG files from graphic design tools often contain open paths, overlapping shapes, tiny fragments, hidden layers, and text objects that need to be converted to outlines. CutArc's import cleanup assistant helps resolve these issues automatically, but complex files may need manual review.
How CutArc Handles Both Formats
CutArc imports both DXF and SVG files and converts them to the same internal path representation. Regardless of which format you start with, the result is a set of clean, closed toolpaths ready for kerf compensation and G-code generation.
For DXF files, CutArc's importer reads lines, arcs, circles, polylines (including bulge arcs), and lightweight polylines. It auto-detects units when possible and offers a scale override when it can't. Layer information is preserved so you can selectively include or exclude parts of the drawing.
For SVG files, CutArc parses path commands, basic shapes (rect, circle, ellipse, polygon), and transforms. It flattens groups and ignores non-geometric elements (gradients, filters, text styling). The import cleanup assistant flags common issues — open paths, zero-length segments, self-intersections — and offers one-click fixes.
Bottom Line
The "right" format depends on where your design comes from. If you're working from CAD drawings and engineering data, use DXF. If you're working from graphic design files, logos, or web downloads, use SVG. Both formats produce identical results once imported — the difference is in the workflow that gets you there.
If you have a choice, DXF is generally easier for plasma cutting because the geometry is cleaner and units are more explicit. But if your design exists only as an SVG, don't convert it to DXF first — import it directly and let the cleanup tools handle any issues. One less conversion step means fewer opportunities for geometry to degrade.