Hi Chris, there seems to be a category of I guess maybe vinyl cutting type machines that have some software that seems to work ok with full splines in DXF format.

Some people have found that conversion utility helped them get curves into their cutting software even though it only converts full splines and does not do conversion to arcs.

Maybe in those cases the bundled software for the machine is doing arc conversion itself or something like that.

But at any rate I do know that export to DXF with full splines without arc conversion has helped some people for particular CNC work before.

I don't doubt that for other purposes arc conversion would be required - there is a lot of variation between different types of CNC use and different kinds of receiving software.

- Michael

Hi Michael,

Yes, it would depend on what you are doing with the file for any conversion issues to become significant.

Most modern vinyl cutting software accepts splines or bezier curves. These are converted into HPGL instructions to send to a vinyl cutter. HPGL has no native support for spline or bezier curves, and relies on the "host" software to do the conversion. Generally speaking, there is less of an opportunity for spline conversion issues to have an impact on output with vinyl cutters than with CNC routers. Vinyl cutters have little to no offset applied to the toolpath. CNC routers, on the other hand, may have a large offset (the radius of the cutting tool). Any problems with spline conversion may be compounded by the size of the cutting tool that is used.

Also, since parts cut by a vinyl cutter do not have a visible edge, vinyl is forgiving of all but the most obvious errors. However, parts with a thickness can be sensitive to a poor spline conversion, and, without some human intervention prior to actually cutting the part, can produce results comparable to a hacksaw.

Chris