I think almost every software has it's own methods of madness. Some give options for exporting methods to different formats, while others may not. If you can convert your splines into nurbs, that might be of help. Exporting as an .IGES, .STL, 3dm, or solidworks file, might work. Usually when I find a method that works, I write it down, so as not to go through the madness to find the method again.