I import vectors from Corel Draw 12 into AC3D using either DXF or TTF as an exchange format.
AC3D does not support Beziers. It does have a "spline" tool which smooths a line, but you cannot alter the control nodes after the transform. Most people who are building curved surfaces directly in AC3D use a technique called subdivision surfaces instead. You can read a very detailed explanation here:
http://www.gamasutra.com/features/20.../sharp_pfv.htm Or a shorter explanation here:
http://en.wikipedia.org/wiki/Subdivision_surface
As far as 3D printing, I think that depends on what file format your particular printer needs. Do you know what file formats it will import? Some people have used AC3D for making CNC models using Cut3D:
http://www.inivis.com/forum/showthread.php?t=4236