The Making of The Goblet of Fire
TLC reports that there is an article in Film Review on the Making of The Goblet of Fire. Not much was given, but this is what they had on it:
"Surprisingly, many of the visual effects were physically created before they were enhanced on computer graphically. The 30-foot maze that features in the tri-wizard tournament was actually built at pinewood studios before it was replicated to feature in the Scottish valley where Hogwarts is situated. Of more epic proportions the crew had the mammoth task of constructing a 40 foot long dragon, which could roar, lash its tail ferociously, and breath fire the same length as its body.
Life like silicone dummies of the children were created for the lake scene, able to move and emit bubbles from their mouths when underwater."
..."Similarly the elaborately grotesque appearance of Mad Eye Moody was created through prosthetic make-up rather than in post-production as the studio originally requested. "