I am a Modo-User, and Modo can open Solidworks parts/assemblys. With this plugin here : http://www.thefoundry.co.uk/products/modo/plugins/power-subd-nurbs/ you should be able to convert to MOI via 3dm/SAT/Igs. I don't own the plugin, so i don't have any clue how good it works. If it works, it should be the cheapest way to convert from Solidworks to MOI. You could ask some of the MODO-guys at the MODO-Forum : http://community.thefoundry.co.uk/discussion/forum.aspx?f=32