I removed a bit about 2001: A Space Odyssey using rotoscoping. 2001 was notable for extensively using a two-pass motion-control matte technique, with a black-and-white matte pass, and a second beauty pass with the same move. This was done in preference to bluescreen or rotoscoping simply for the very high quality of the final composite. I can't say definitively that there was no rotoscoping used, but if it was used, there was very little of it, and I can't see it. Perhaps we should ask Douglas Trumbull  he would know.