Animations for non-player characters in Hitman: Absolution were pre-scripted and story-driven, but still melded with a responsive AI for combat in order to create realistic "breathing" moments, according to members of the development team.
Speaking in a panel today at the 2013 Game Developers Conference, IO Interactive senior software engineer Maurizio De Pascale and senior AI programmer Mika Vehkala said each individual NPC's behaviors and responses to player-controlled character Agent 47 were programmed in ways that made sense to the story.
"The developers were careful to make sure that each NPC's reaction to Agent 47 had a reason and fit the situation," Vehkala said. Where this feature was not present, the team went back and scripted it in. NPCs will also enter situations if they are within the radius of another reacting NPC.
"None of your fancy AI matters, and you can replace it with a random bot unless you have story in your dialogue and animation," Vehkala said.
De Pascale added that the AI and animations were designed individually and then combined, in order to preserve the purpose and relevance to the story in NPC actions.
"Today, animation is more complex and less predictable," he said, "The line between what is AI and [a pre-scripted] animation is often blurry."
De Pascale said that it would have been easier to animate all interactions, but that would make combat scenarios "entirely predictable." The developer therefore "micromanaged" the AI and added in story-driven animations after it had been scripted.