I sometimes have the same problem in needing to have only lines and arcs for some of my CNC work.

I suggest you download CamBam and use its Arc Fit tool to convert hundreds of short lines into arcs, or alternatively, use the Convert To Polyline tool to alter a spline curve into a polyline of lines & arcs.

CamBam gives you 40 totally free sessions before gcode output is limited. However, I *think* you can use all the other functions for free once this time has passed and this should include the facility you are after of being able to export back out a modified DXF file.


Martin.