CIS 588 AI Evaluation for World of Warcraft

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CIS 588 AI EvaluationforWorld of Warcraft

• Jonathan Schmoll
• February 14, 2005

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About World of Warcraft

• Henceforth referred to as WOW
• Created by Blizzard Entertainment
• Release November 23, 2004
• Currently the 1 game in its genre
• WOW is a MMORPG
• Massively Multiplayer Online Role Playing Game

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Artificial Intelligence in WOW

• Used to control (mainly) enemy NPCs
• Used in almost all enemy functions
• Movement
• Attacking
• Social Behavior
• Some scripting used for special encounters

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WOWs AI Implementation or Blizzard Doesnt
Care That Im a Grad Student Doing a
Presentation On AI

• Uses a strongly rules-based approach
• Apparently based on expert systems
• Special scripting does not break AI rules
• Possibly uses Lua scripting language
• Blizzard did not want to divulge their secrets
• Info based on obtuse contact with Blizzard,
  Internet research, and a lot of forum trolling.

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AI Behavior Study

• The following slides detail the adventures of
• Johnny the Human Priest
• during his study of WOWs creature behavior.

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AI Behavior Study

• Terrain Navigation
• Creatures will generally move straight at the
  player.
• Creatures will move around obstacles and over
  mountainous terrain.
• Terrain that restricts players also restricts
  creatures.

This Primitive Owlbeast is pumped.
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AI Behavior Study

• Terrain Navigation (cont.)
• Some creatures will not follow you into water.

Now whos tough, Mr. Cant Swim.
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AI Behavior Study

• Creature Aggression
• If a creature knows it can kill you, it will go
  out of its way to attack you.
• Simulates how much a creature fears a player.

Obviously this dragon isnt too afraid of me.
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AI Behavior Study

• Creature Aggression (cont.)
• Weaker creatures will not attack until the player
  is very close.
• Some creatures will regard the player as neutral.
• Some creatures will attack other creatures.

This is why you dont leave your chickens out.
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AI Behavior Study
This is where I run away.

• Social Behavior
• Some creatures will call out for aid if they are
  attacked.
• Less intelligent creatures (like beasts) will not
  help their comrades.

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AI Behavior Study

• Fleeing
• More intelligent humanoid creatures will
  attempt to run when they are about to die.
• Beasts will fight to the death.

This is bear is going down. Hard.
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AI Behavior Study

• Movement
• Some creatures will patrol a certain path.
• Some creatures will wander around a certain area.
• Some creatures will just stand around like goons.

Move along fellas, you dont want none of this.
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AI Behavior Study

• Attack Range
• Ranged attackers will attempt to keep their
  distance.
• Melee attackers will get right up in your face.

This troll didnt appreciate my Jolly Green Giant
jokes.
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AI Behavior Study

• Special Abilities
• Some creatures have special abilities and will
  use them during battle (for example, healers will
  heal their comrades and themselves.)

Whitemane revives her buddy while my party
members take a nap.
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AI Strengths Weaknesses

• Strengths
• Relatively Bug-free
• Doesnt feel cheap
• Works well for the MMORPG genre
• Is difficult to exploit
• Is predictable

• Weaknesses
• Doesnt learn
• Has limited options
• Is predictable

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AIs Effect On Gameplay

• Creatures first appear very smart
• This lends itself very well to the small player
  in a big world filled with monsters adventure
  aesthetic.
• The AI is fairly transparent
• This sounds like a bad thing, but it isnt. As
  your character grows, so does your
  understanding of creature behavior.

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AIs Effect On Gameplay (cont.)

• The gameplay changes as you level up.
• Since high level players have seen most of the
  game world, the adventure aesthetic becomes less
  important.
• Game play becomes more strategic.
• Creatures are extremely powerful at high levels.
  Unpredictable behavior would be frustrating when
  there is a penalty for dying and there is no
  reload option WOWs persistent game world.

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AIs Effect On Gameplay (cont.)

• Scripting adds flavor
• Scripted creature behavior inside special
  dungeons adds a controlled unpredictability to
  the game. Players are forced to quickly come up
  with solutions to these puzzles.
• Scripted events still work within the creatures
  AI rules (for example, a healer will not suddenly
  begin performing warrior abilities.)

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Questions / Comments ?
Who doesnt like a little gnome-on-human dancin?