Hi Ken, you won't get a "feature tree" when transferring using standard file formats like IGES or STEP but you can use the so-called "direct modeling" features that many CAD programs have to edit faces in various ways like moving or rotating planes, changing hole diameters and stuff like that. Something like a tentacle arm is not going to fit well with that kind of direct modeling toolset though, it's not likely that it will be able to reverse engineer how that particular surface was created. So for editing a tentacle you're probably looking at just drawing a brand new shape for it rather than doing any editing for that particular case.

> What would be the best way to export, iges?

It's probably better to try STEP first - IGES will also work but the IGES file will contain a bunch of individual separate surfaces and the receiving application needs to sew them back together again into a solid, which it probably will do ok but with STEP format the joining information comes through as part of the file.

- Michael