Attached is a summary of what I have seen so far (from a purely software point of view) with respect to the use of Inkscape .dxf files in desktop cutting :
- the 'Desktop Cutting' export option supports two basic types of object : lines and cubic Bezier splines.
- it may sometimes be necessary to use the menu option 'Path | Object to Path', to convert rectangles, or ellipses, or text, before exporting to .dxf.
- the exported .dxf file complies with the Autodesk dxf spec to the extent that it can be viewed using Autodesk software such as Volo View Express 2.01 and DWG TrueView R17 (2008).
- the exported .dxf file can be both edited and viewed using QCad from RibbonSoft.
- the desktop cutting software program Winplot V6.8 from Summa has been tested on .dxf files. It will load .dxf files, but it does not render the spline correctly : a cubic Bezier spline consisting of four points will be rendered as a combination of a circular arc based on the first three points, and a straight-line segment based on the last two points. The developers at Winplot have been made aware of this issue, but it is not likely that it will be addressed, see https://bugs.launchpad.net/inkscape/+bug/192923/comments/36 . Luckily, in this case there is a workaround, namely use 'Postscript via Cairo' export, which can be read properly by Winplot, see https://bugs.launchpad.net/inkscape/+bug/168411/comments/17 .
- the desktop cutting software program ROBO Master-Pro Version 4.3 from Graphtec has been tested on .dxf files. It can read .dxf files, and as far as I can tell, it is also rendering them correctly on the screen. However, any attempt to edit a spline that originated from a .dxf file will immediately lead to a software crash. Also, even if this file is saved as a native .GSD format file, and then reloaded as a .GSD file, it will still crash when attempting to edit the spline : which suggests that this is not specifically a .dxf issue, but a more general problem. Also, the ROBO Master software supports the creation and editing of a spline starting from scratch, but the mathematical form of the spline they generate does not appear to be compatible with the cubic Bezier spline that Inkscape uses. I am attaching a .GSD file with both types of spline present. The cubic Bezier spline is not editable (you'll be sorry if you try), but the native ROBO spline is editable. However, no matter how hard I try, I cannot make the two curves superimpose on each other, and I believe they are mathematically incompatible. I have emailed ROBO Master concerning this issue, and will await their response.
- I should not speculate, but I suspect that this mathematical incompatibility may be the source of some of the mechanical stuttering that has been reported. In any event, it would be a relatively simple matter to produce a reasonable approximation of one spline curve to another, based on matching slopes and curvatures at vertices, but before this is done we need a mathematical description of the shape of the curve that ROBO Master uses.
Alvin Penner http://www.nabble.com/file/p17843712/demo.GSD demo.GSD