Would be cool to have a part which makes everything it touches transparent. Or at least makes everything it touches clear/hollow. Would be a great tool to make stuff like passenger windows into fuselages so that you can actually look out of and into the aircraft cabin.
@Phoebe Yes I know about fuselages and paneling lol. I mean making a hole on the side of a fuselage. Yes you can do it with paneling and all that stuff but it would be a lot easier if you could have just one part that makes a hole anywhere you want. Plus you can then easiely move it or resize it if you need.