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 NPC’s: • 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 • NPC’s use the mesh to move to an area and not a specific point in map, which makes it easier to avoid objects

7. NavMesh • NPC’s 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

9. 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

10. Goal Oriented Action Planning • Each action has it’s 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 • NPC’s send information about the player’s 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 NPC’s 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)

13. 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. • NPC’s 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.

14. Strengths of F.E.A.R AI • Good defensive behavior of NPC’s. 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 player’s attention the others look for ways sneaking behind him. • Good use of weapons. The NPC’s 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 NPC’s 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 • NPC’s 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 NPC’s 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. AI’s 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 player’s part • Player needs to constantly adapt to current situation in the game • The game takes more time to finish