Well, even if it did ( obj ), that's not what you want. Obj would hold the geometry as polygons not as nurb surfaces which is what I think your wanting to preserve.
And I don't think you can import iges directly into Houdini without some possible unwanted results.
This software here does support the conversion of a SW part file to fbx. But I don't know that file format too much - I think it is used more for like a container for a scene rather than geometry object.
https://www.okino.com/conv/filefrmt_3dexport.htm [
www.okino.com]
The software does support converting SW or iges to obj though. Maybe might be able to find a free converter too.
And, if you did use obj you could convert it to a volume within Houdini, if you don't want the triangulated polygons.
But from that point on, I don't think there is anything you can do much to get the volume back into a nurbs surface - unless of course you use the imported obj file as a reference to build your nurbs.
I was curious - it seems .abc supports nurbs and Houdini has an import alembic node but I could not find any convertors for SW or even iges to .abc.
You might want to re-consider working with plygons ( some of which might be triangulated rather than just quads).
If you have high enough polycount you can easily make surfaces indistinguishable from a nurbs surface.
I use to make models in SW and 3d print them…I now do that with Houdini ( that has lots of triangulated polygons )..and there's no way one can tell from the resulted printed models - if it was originaly from a nurbs or poly model.
Of course, this is a moot point since in either case both are converted to .stl
Again, depends on your intentions.