Double yay! I am mostly using QCAD, but I have also used OpenSCAD to make a 2D projection of a model, which can then be exported as DXF.
The other thing is you can use your favourite CAD software to make the DXF. Obviously, once you have the G-Code file you can load it up onto the Maslow. Some DXF file -> DXF2GCODE -> G-Code file
