DXF viewer & CNC check
See your drawing and find what will stop it cutting: open outlines, tiny gaps, duplicate lines, splines and stray text. Free, no signup, and the file never leaves your computer.
What the CNC check looks for
- Open outlines
- Lines and arcs that don’t meet end to end, so the part never closes.
- Tiny gaps
- Endpoints less than 0.1 mm (0.005″) apart that look joined on screen but aren’t.
- Duplicate or overlapping lines
- Paths drawn twice, which cut twice and confuse outline detection.
- Splines and ellipses
- Curves many cutting tables and older CAM posts can’t read. Convert them to arcs or polylines.
- Text on cutting layers
- TEXT/MTEXT on a layer not named for labels, which some tables try to cut.
- Zero-length lines
- Degenerate geometry that can trip post-processors.
Units come from the file’s $INSUNITS header; drawings without it are treated as millimetres.
Frequently Asked Questions
The usual causes are outlines that are not closed (a line stops just short of the next one), duplicate lines drawn on top of each other, SPLINE or ELLIPSE entities the software does not support, text on the cutting layer, and wrong units. Drop the file into the viewer above: the CNC check lists each of these and circles where they are on the drawing.
Open it in this DXF checker. It reads the file in your browser and reports open (unclosed) outlines, gaps between endpoints smaller than 0.1 mm (0.005" in inch drawings), duplicate or overlapping lines, splines and ellipses, TEXT/MTEXT on layers not named for labels, and zero-length lines. If none are found it says CNC-ready.
An outline is open when its lines and arcs do not meet end to end, so the shape never closes. A cutting table or nesting program cannot tell what is inside the part, so it skips it, cuts the wrong side, or refuses the file. Join the endpoints in your CAD program (for example PEDIT → Join in AutoCAD) and check again.
Many plasma, laser and router controllers and older CAM post-processors only understand lines and arcs. Splines and ellipses get rejected or broken into thousands of tiny segments that make the machine stutter. Convert them to polylines or arcs before sending the file.
No. The file is read and checked entirely in your browser. Nothing is uploaded, and you don't need an account. If you click "Nest these parts", the file is passed to the optimizer in the same browser tab session, still without uploading it.
LINE, LWPOLYLINE and POLYLINE (including arc segments), CIRCLE, ARC, ELLIPSE and SPLINE. Splines are previewed through their fit or control points. TEXT and MTEXT are counted and checked but not drawn. Block references (INSERT) are not expanded.
Yes. Click "Nest these parts" after the check. The optimizer opens with the closed shapes from your drawing ready to import, so you can lay them out on sheets and export a cut layout or a new DXF for your machine.
Nest your parts on sheets
Import DXF parts into the nesting optimizer, lay them out on your stock, and export a cut layout or a clean DXF for your machine.
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