Train of Thought is a short film in paper by Leo Bridle and Ben Thomas. Although it used digital compositing software, all the animation and models were done by hand, not with CGI. The film took approximately nine months to complete, from storyboards through to the final edit. [HD on Vimeo]
Age progression compositing (or forensic composting) is the process of taking a photo of a child and creating a composite image of what they might look like years later. It has been used to great success in the recovery of kidnap victims, and most recently in the case of Jaycee Dugard.
“Thirty-six characters from different stages of life - representations of different times - interact in one room, moving in loops, observed by a static camera. I had to draw and paint about 16.000 cell-mattes, and make several hundred thousand exposures on an optical printer. It took a full seven months, sixteen hours per day, to make the piece”[ source]: Zbig Rybczynski on the making of his award winning (and much imitated) animation "Tango "(YT, mildly NSFW).