I investigated this yesterday and with nothing to add, I got a segmenty line in an extruded solid which carried through to the drawing. But with Bill's trick, putting the spline in the drawing, it comes out smooth for some reason, and I have my 'Options' smoothness cranked all the way up. Not sure what is happening. Saving as a pdf and printing to Acrobat as a pdf both wind up with segments when zoomed in. Saving it as a DXF and opening it in Adobe Illustrator it comes out smooth. Importing into
PlasmaCAM it has segments. It is below any tolerances in real life for me so the segments are negligible. FYI
-Christian