Re:Tron had great design... (Score 1)

For the most part, the overall look of the film was done optically. The whole "glow" esthetic was acheived by countless hours of classical animation on celluloid. There are still a few integrations of real CGI which do stand out.

from article:

"Parts of the film were done by shooting live action then doing rotoscope and other optical techniques over the top of it"