What Is a DXF File and Why Does the Industry Use It?
DXF (Drawing Exchange Format) was developed by Autodesk in the early 1980s as an open file format for sharing 2D geometry between CAD applications. It stores lines, arcs, splines, and polylines with precise coordinates -- no proprietary data structures, no software lock-in. That openness is why the CNC manufacturing world still runs on DXF decades later: any CAD program can write one, and any CAM or nesting software can read one.
When you upload a DXF to Can-Cut, our system parses the geometry, calculates cut length and pierce count, nests parts onto a sheet, and prices your order automatically. The quality of that process depends entirely on the quality of your file.
Software That Exports DXF
You have options across every budget:
- Fusion 360 -- popular among hobbyists and professionals; exports DXF from the sketch environment directly
- AutoCAD / AutoCAD LT -- the industry standard; exports DXF natively in any version
- SolidWorks -- export DXF from a flat drawing or a sheet metal part's flat pattern
- FreeCAD -- free and open source; supports DXF export from the Draft and Sketcher workbenches
- LibreCAD -- free 2D CAD, simple and capable; exports DXF well
- DraftSight -- free tier available; familiar AutoCAD-like interface
- Inkscape -- free vector design tool; can export DXF but with important caveats (see below)
Inkscape caveat: Inkscape is a graphic design tool, not a CAD tool. It works in unitless canvas space and its DXF export can produce geometry that is scaled incorrectly or contains open paths and stray nodes. If you use Inkscape, verify the output in a CAD viewer before uploading and always confirm the part dimensions after upload.
The Single Most Important Rule: Closed Paths
If your paths are not closed, the part cannot be cut correctly.
A closed path is a loop with no gap -- the endpoint of the last segment connects exactly to the start point of the first. An open path has a gap somewhere, however small. The plasma cutter needs a closed loop to know what is inside the part and what is outside.
Common causes of open paths:
- Snapping tolerance too loose in your CAD application, leaving a tiny gap at a junction
- Copying geometry and nudging it slightly, creating near-coincident but disconnected endpoints
- Importing from another format (SVG, DWG, PDF) that did not preserve connectivity
Most CAD tools have a "close polyline" or "join" function. Use it. In Fusion 360, the Sketch environment will highlight open chains in yellow if you run the Close Sketch command. In AutoCAD, PEDIT > Join merges segments into closed polylines.
Other Common Mistakes
Duplicate or Overlapping Lines
If two lines sit on top of each other, the torch will travel the path twice -- doubling cut time and burning the edge. This is common when geometry is copied from a reference layer without cleaning up the original. Check for duplicates with your CAD tool's audit or purge function, or by selecting all and looking at the properties panel for unexpected line counts.
Features Smaller Than the Material Thickness
Plasma cutting removes material in a kerf approximately 0.060"-0.090" wide. Features smaller than the material thickness -- narrow slots, tiny holes, sharp internal corners -- either cannot be cut cleanly or will burn out entirely. Can-Cut flags features below 1/16" (0.0625") automatically on upload.
As a general rule: minimum hole diameter should be at least equal to material thickness, and slot widths should be at least 1.5x the thickness.
Text Not Converted to Outlines
If your DXF contains text objects rather than geometry, the cutter has nothing to follow. Convert all text to curves or outlines before exporting. In Fusion 360, use the Explode Text option in the sketch. In AutoCAD, use TXTEXP to explode text to individual line entities, then trace or convert to polylines.
Wrong Units
DXF files store geometry in drawing units, but "drawing units" can mean inches or millimeters depending on how the file was set up. The $INSUNITS variable in the DXF header tells downstream software which unit to assume.
Can-Cut's parser detects the unit setting and will ask you to confirm if it looks ambiguous. If your part comes out 25.4x too large or too small, a unit mismatch is almost always the culprit. Check $INSUNITS in your CAD application's drawing settings: 1 = inches, 4 = millimeters.
Self-Intersecting Paths
A path that crosses itself creates ambiguous inside/outside regions. The nesting and cutting software cannot reliably determine where to cut. Most CAD tools can detect self-intersections -- run a geometry check before exporting.
Islands (Holes Inside Your Part)
Islands -- enclosed cutouts inside the outer boundary -- are completely normal and well-handled. Each island is a separate closed path nested inside the outer profile. The cutter pierces the sheet for each island separately, cuts it out, then moves to the outer perimeter. More islands mean more pierces and slightly longer cut time, reflected in the price. There is no limit on how many islands you can have.
Part Size and File Limits
Can-Cut's cutting table has a 48" x 96" working area. No single part can exceed those dimensions. If your part is close to the limit, account for the nesting offset margin (approximately 0.5" around the sheet boundary).
The file size limit is 10 MB per upload. DXF files are geometry data, not rasterized images -- they are almost always under 1 MB. You would need an extraordinarily complex file to hit 10 MB.
No CAD Software? Use the Drawing Board
If you don't have CAD software and your part is a straightforward shape, Can-Cut's browser-based Drawing Board at /drawing-board lets you draw your part directly in the browser and export a DXF. It handles rectangles, polygons, circles, and basic boolean operations. No download, no account required.
What Happens After You Upload
Can-Cut's automated validator checks your file on upload:
- Detects open paths and flags them with a visual indicator on the part preview
- Measures the bounding box and checks against table limits
- Parses all geometry to calculate cut length and pierce count for pricing
- Displays the part at actual dimensions so you can verify scale
If something is flagged, you will see a message explaining what was found before you proceed to checkout.
Upload Your DXF at Can-Cut
Upload your DXF at can-cut.ca and get an instant quote -- no account required. The entire process from file upload to priced quote takes under a minute.