Can you post to the forum for illustrator, as you will need to specify the dxf version in the exdxf plugin when you execute the export of the file. What is happening when you use v2004? v12 dxf does not use splines and converts the splines to polylines. Are there a lot of splines in your patterns, maybe you could convert them to polylines in Illustrator before exporting to dxf?
Regards Jason
Regards
Jason