So here is an update to the export script that generates a proper LAYER table, allowing a wider variety of toolpath generating programs to import them correctly. I dug up a copy of the DXF spec, played around a bit and found that these programs expect all layers to be formally declared in a DXF LAYER table in the header section of the file before use. In practice, many of the same free/OSS, low-cost and weekend-warrior tools do not handle this any better than splines. In theory, the layer support as he implemented it ought to work (it’s correct and in conformance with the DXF spec, which allows drawing objects to be assigned to arbitrarily-named layers throughout the file). It also adds some support for layers, including special ‘drill’ layers whose drawing objects will be output as single points (no lines) for hole drilling. Also, if the drawing contains curved (Bezier) lines, these will be exported more or less as-is (DXF splines) and many free/cheap/itch-scratch-ware programs will not handle the resulting file (since the ‘correct’ representation or interpretation of splines is never disclosed in the published DXF file specifications, so everyone kind of does them in their own way, with less-than-stellar results).īob Cook noticed these limitations and updated the script to fix many of the ‘unusual transforms’ scaling issues, and convert Beziers to standard polylines that any program will import. Converting some files, I discovered the current export script does not correctly handle all types of transforms, so some parts of the file may export out-of-proportion to each other or in strange size units regardless of the drawing units of the original drawing (Inkscape’s internal drawing unit is apparently equal to 1/90 of an inch, wait, wtf?).
I started using Inkscape, a sweet open-source vector graphics program, to produce (and/or steal from the internet and convert) designs suitable for carving on the CNC as Inkscape has a plugin to export the file as a.
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