Hey here the swan converted to solid nurbs the first is an IGES and the other a step file made with Moi3D the conversion was made in two different ways the IGES with my tips and tricks here https://blenderartists.org/t/from-blender-subdivision-to-n-u-r-b-s-iges-for-free
IGES only 7mb https://mega.nz/file/B8l1hBjJ#m2XmC_hYQjA_npe5lygtHZRaCN51tZOjZM9T0JzJq3w
Step Solid but huge over 170mb
https://mega.nz/file/kw8lGZ7C#8ijriNJA6CzoCK27cygcSjXumQps2L68DrbDVMXK7Mw
here the file for FreeCAD https://mega.nz/file/N0khTZRY#hcTaXVHa8bZ1a70wut03N0V4Fz9UQ_J-S7flUpZzt-8
