SilverWook said:
The ending scene for Episode III was originally shot on location in Tunisia during production on AOTC, but was reshot in the studio on ROTS.
http://www.starwarz.com/tbone/special-deliveries/
Crews were dispatched to various locales to shoot background plates for Mustafar and Kashyyk, but it does seem the main unit never left the studio.
The same as Crystal Skull. Background plates were the new location shooting for the jungle scenes and waterfalls. Though other sets the college, the restaurant/bar, new Mexico and Peru were real. Or at least i think they were.
The clone troopers and pilots in Episode II and III were cgi using the actors likeness for jango and boba. No stormtropper like suit of physical armor was made or used no actual human was shot playing those roles.
The precursor to the X-wing, Tiefighter ships were all cgi in II and III. The stardestroyers or republic cruisers were all faked in cgi. Well at least Hayden Vader's suit was real but he was too short to match Prowse height.