Maya Modeling :: How To Convert Parametric Models Created In CAD

I often create animations for technology companies, and they give me models that were created in programs like alias, rhino, AutoCAD, or solid works. They export for me in IGES, or STEP, and the models, while amazingly intricate, are too much for Maya on my 24GB RAM 12-core machine to take. They take upwards of 20 minutes just to open.

I want to convert these to ploys and generally make them easier to work with. What are my options for making these manageable, and still look good when they render. The flat edges and services are fairly easy to convert, it's the rounded bevels that don't look so good if I convert everything to Polys all at once. And there are usually hundreds of curved surfaces to convert, so doing them one at a time is far too cumbersome to be effective.

Also, how would I go about taking surfaces for objects in joining them together to create a complete object made of Polys? For example, a small part may be made of 35 difference parametric surfaces in solid works, and exports as that in IGES, so when I imported into Maya, it really should be just one object made of Polys.

need to convert parametric cad objects to poly to make them manageable and to make renders faster.