When I assemble Surface MEshes from imported IGES files, containing hundreds of 3rd degree UNTRIMMED NURBS patches, XSI 1.0 crashes.
Also how are polygonal OBJ files imported into XSI?
Dave Rindner
digital sculpture animation
www.dsanimations.com
You'll need to use that plugin that came with your copy of XSI 1.0. I believe it's called SI3.9. 
Anyway, all kidding aside, use Softimage's "Tools" view to access the import menu and you'll have access to importing .obj (wavefront) files. Save out from SI as a scene and use "import" within XSI and that's it.
Russ
That does not seem to work.
The OBJ models are polygonal, of varying amounts of polygons. Some are from Rhino (tesselated from NURBS) some are from formZ. The message I get from SI 3.9 Extreme is "No Data To Import". The obj files import fine into 3DS MAX.
Why is there no OBJ importer in XSI? Seems like a minor thing. Every animation app has OBJ import.
Dave Rindner
digital sculpture animation
Part of my routine is to use Lightwave for poly modeling and export the models in .obj format. I have had no problems importing into Softimage(then into XSI) or Maya. As long as I make sure the ".obj" suffix is in the file name, the files import with no fancy steps required. Maye you should try loading the files into LW if you have it and export in the wavefront format.
Good Luck