See, that was my point - I'm pretty familiar with dealing with raw scan data and it seems like just a massive, unnecessary headache to data wrangle, not to mention risk potentially introducing unwanted clean-up and simplification of the geometry as the artist tries to boil the data down to relevant points, compared to just starting with the original file. Painting and aging wouldn't be an issue, as that's all going to happen after they produce the physical item anyways, but I suppose I can see how something complex might end up having the art department modify it further though. Cheers!
Perhaps I was not clear. Movie props and costumes, complex or not, are not "Draw it, Print it, Film it". Many (most I've work with) directors, designers, producers, cannot look at a drawing, not even a 3d one, and be sure they like what they see. So most props and costumes are sculpted or if they are printed, they go though many alterations and steps before the final product ends up on set. In fact one of the problems with 3d printing is you can now draw and print almost anything, and just because you can....is often the reason you shouldn't. There is much more to a film's total look, then the designers initial idea. Once on set, or in front of camera, often things don't look good or as you thought they would.
Take Vader's helmet as an example. The idea and very likely the original was painted all gloss black. But on camera, it does not read well, so you paint some areas dark gray, and to the camera and you the audience, it looks like an all shiny black helmet, when it is not.
On the film "Bram Stokers Dracula", we spent two days putting a two tone, air brushed lacquer paint job on Gary Oldman's armour. The designer, Eiko Ishioka, was very, very particular to the colors used. But, when it got to set, on direction from the art department head, the on set painter "aged" it with tempera paint mixed with floor wax and completely changed the look.
Just some examples of how fluid a film set can be.