F.E.A.R.

1
F.E.A.R.

• Game AI Evaluation
• by Robert Rak

2
What is F.E.A.R. ?

• FEAR is a First Person Shooter game
• Player takes on the role of an elite strike force
  team soldier ordered to infiltrate an aerospace
  compound taken over by unknown paramilitary
  assailants
• Main objective is to eliminate any hostile
  presence in the compound and to determine the
  reasons of their attack

3
F.E.A.R. Development

• Developed by Monolith Productions
• Utilizes Jupiter EX game engine developed by
  Touchdown Entertainment
• DirectX 9 Renderer
• Hovoc Physics Engine

4
How AI is used in F.E.A.R. ?

• Used to control all functions of in game NPCs
• Movement
• Tactics / Squad behavior
• Communication
• Weapon selection
• Firing

5
AI techniques used in F.E.A.R.

• NavMesh
• Description of spatial relationships
• GOAP
• Goal Oriented Action Planning
• NPC communication

6
NavMesh

• Used to define areas of the map where the NPC can
  move instead of waypoints
• Consists of groups of polygons defining a
  specific area, which can be used collectively to
  specify possible movement paths
• NPCs use the mesh to move to an area and not a
  specific point in map, which makes it easier to
  avoid objects

7
NavMesh

• NPCs use knowledge of the mesh to select best
  movement paths for flanking, area search, and
  other tactical scenarios
• Polygons in a NavMesh can be flagged with special
  links, which trigger specific actions depending
  on the environment like opening doors, using
  ladders, jumping over obstacles, take cover
  behind objects

8
Goal Oriented Action Planning

• Goals and actions needed to fulfill that goal are
  determined in real time
• GOAP approach makes the NPC behavior less
  repetitive and predictable
• Real time action planning allows to react and
  adopt to changes in the environment

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Goal Oriented Action Planning

• Planning system inputs
• Current state of the world
• Goals to be satisfied
• Possible actions
• Planning system outputs
• Plan consisting of valid sequence of actions

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Goal Oriented Action Planning

• Each action has its preconditions, which need to
  be met at the time of execution to be valid
• Each action has an assigned cost metric, which is
  used in the process of defining a plan

11
NPC Communication

• Enemies use audible communication during gameplay
  reacting to the player actions
• NPCs send information about the players
  location when spotted or tactical movements like
  flanking
• AI characters recognize for example the death of
  a teammate, can mark a region as dangerous for
  other NPCs to avoid, or call for backup when
  needed

12
AI Implementation Tools

• Description of used tools is incomplete
• Content Creation Tools included with the Jupiter
  EX game engine
• World Edit
• F.E.A.R. Public Tools
• Specify NavMesh with special links
• Add AI characters into the level
• Define actions for NPC through script (patrol,
  attack)

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Strengths of F.E.A.R. AI

• Actions for accomplishing goals are defined in
  real time making the game less repetitive.
  Enemies attack using different tactics in the
  same area of the map.
• NPCs are aware of the surrounding environment
  using it for taking or creating cover from
  hostile file.
• Communication between team members allows for
  implementation of better tactics, like
  regrouping, calling for backup, flanking, taking
  cover.

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Strengths of F.E.A.R AI

• Good defensive behavior of NPCs. They can move
  backward while looking for cover and shoot at the
  same time to defend themselves.
• Using squad tactics. While some squad members
  draw the players attention the others look for
  ways sneaking behind him.
• Good use of weapons. The NPCs can use the
  appropriate type of weapon depending on range and
  situation.

15
Weaknesses of F.E.A.R AI

• Easy to manipulate. By shooting in a specific
  area, the player can lure the AI characters into
  a trap.
• Predictable after a time. After analyzing the
  behavior of NPCs in similar situations their
  actions can be predicted and used as an
  advantage.
• Incorrect patrolling behavior. While patrolling,
  AI characters do not look around enough and
  ignore checking obvious danger areas making it
  quite easy to sneak up on them.

16
Weaknesses of F.E.A.R. AI

• NPCs leave good cover spots too quickly
  revealing themselves to enemy fire.
• No cancellation of actions in progress. Once an
  action to move from one place to another has been
  initiated, the NPCs will carry it out no matter
  what, even if he will get under heavy fire.
• AI characters are not always ready to fire and
  can be surprised easily. They can walk from
  behind a corner without checking if it is safe
  and are not ready to fire if there is such a need.

17
AIs Effect on Gameplay

• The game is less repetitive making it more
  entertaining
• AI characters present a good level of
  intelligence posing more of a challenge for the
  player
• Requires more tactical thinking on the players
  part
• Player needs to constantly adapt to current
  situation in the game
• The game takes more time to finish