Hi Chris, a spline-to-arc conversion for DXF output is something that I would like to add but that probably won't come in the first round of work on this area. I'm not quite sure how much work it involves to make a good quality conversion, I think it's kind of easy for that kind of converter to produce arcs that sort of wobble back and forth quite a bit.

I'm pretty sure that Rhino has a good method for doing a conversion to arcs, so right now if you need that kind of conversion of splines to arcs using Rhino is probably your best bet.

- Michael