Director Peter Jackson had laid down his requirements for the Battle of Pelennor Fields - the climactic engagement in The Return of the King in which the heroic defenders of Middle-Earth face the overwhelming might of Sauron and his armies of Darkness. Jackson wanted the computer-generated antagonists to have absolute authenticity on the big screen and to be indistinguishable from the real actors.

"So each of these computerized soldiers is assessing the environment around them, drawing on a repertoire of military moves that have been taught them through motion capture - determining how they will combat the enemy, step over the terrain, deal with obstacles in front of them through their own intelligence - and there's 200,000 of them doing that."

"For the first two years, the biggest problem we had was soldiers fleeing the field of battle," Taylor said.
"We could not make their computers stupid enough to not run away."