[Andy A.]

A little background on IGES and STP-

These formats were made to be easily exchanged between solid body modeling software. As such a STP or IGES file can be opened by virtually any CAD package.

The downside is that the model is stripped of any program specific information. So sketches, feature information, physical properties and so on are gone. It becomes a single solid body, and depending on the geometry, a simplified one at that.

It's kind of like saving a word processor file as a .txt instead of .doc. You know that anyone anywhere will be able to open it, but it's not going to have any formatting when they do. It's a trade off you make solely for interoperability now and in the future. Unless you plan on working across platforms (like inventor and solidworks), STP and IGES probably won't do you much good.

-Local