Hi mike, when you saved out to AI format, did you use the scale option for "Fit to page" or "Preserve units" ?

If you set "Preserve units" and the coordinates of the resulting curves are a far distance away from the origin, it's possible that they would just not show up in Illustrator because Illustrator only works with objects with a fairly limited coordinate range.

If that's not the case can you please e-mail me (moi@moi3d.com) both your DXF file and the generated AI file so I can take a look at them?

- Michael