Attached Link: http://www.fignations.com/resources/home.html

Easy to use? Sorry, the easy to use program is called Moray, but it doesn't export to dxf, it's for POV. The attatched link gives a very comprehensive list of free, cheap, and pricey programmes and utilities. It's really a matter of preference. I personally wouldn't recomend Rhino. It's a very powerful program, and easy to use, but its NURBS only, that can cause some difficulties when you want to export. Try all the freebies first, and see which you get on with. Oh, you can add Blender to the list, though that is incredibly hard to use at first, but amazingly powerful, and free. Also Metasequoia. I think there's a link to that on the modelling forum. regards peejay