Ai relationship

This entity is not in the FGD by default.
See below for instructions on making it available.

Class hierarchy
CAI_Relationship ↳CBaseEntity
ai_relationship.cpp

ai_relationship is a point entity available in Half-Life 2 series, Portal series, Team Fortress 2, Alien Swarm, and Source SDK Bases.

It sets a relationship type between two parties. These parties could be either a single specific NPC by using the targetname of it, or all NPC's of the same type by using the classname instead. I.e npc_helicopter, npc_helicopter, ect.
Any object descending from CBaseCombatCharacter can have relationships, most notably NPCs and players.

To make NPC's change their relationship to the player, set the Target(s) field to !player.
If you set the Disposition of any NPC towards the player to to "like" and then also enable Reciprocal, then the player will lower its weapon when looking at the subject NPC.

Note:While ai_relationship does not exist in Half-Life: Source, the SetRelationship input does work.

Warning:The "Target" and "Subject" field allow for Classname and Targetname. If you were to use Npc_* in either field, every single npc will be affected, because it goes by classname as well.

Bug:Setting npc_zombie, npc_fastzombie, and npc_zombine to like the player, even if not reciprocated, causes the zombie to be immune to thrown sawblades.

Dispositions:

Name	Description
Hate (D_HT)	Considers the target an enemy. Most NPCs will attack if possible, although NPCs that cannot attack may flee instead.
Fear (D_FR)	Tries to avoid/flee from the target. Behavior varies across NPCs. Most NPCs will just run to cover out of the target's sight while NPCs with ranged weapons may run away while shooting at the feared enemy. Bug:The trace code used by melee damage doesn't detect D_FR entities and therefore NPCs can't use melee attacks against them. (they may try, but they won't do any damage)  [todo tested in ?] Code Fix:This can be fixed by going to CTraceFilterMelee::ShouldHitEntity() and replacing pBCC->IRelationType( pEntity ) == D_HT with pBCC->IRelationType( pEntity ) <= D_FR, which correctly accounts for both D_HT and D_FR.
Like (D_LI)	Considers the target a friend. NPCs will never intentionally attack these targets and NPCs with bits_CAP_FRIENDLY_DMG_IMMUNE (e.g. citizens) will not take any damage from NPCs or players that have this disposition towards them. Note:Only the disposition of the NPC that deals the damage is considered by bits_CAP_FRIENDLY_DMG_IMMUNE. If a citizen friendly to the player (citizen D_LI to the player) is attacked by a player that doesn't consider them friendly (player not D_LI to the citizen), they will take damage and may not retaliate without additional programming. Code:bits_CAP_FRIENDLY_DMG_IMMUNE can be added to a NPC with AddCapabilities and is usually appended in an NPC's Spawn() function, although it can be toggled at any time.
Neutral (D_NU)	Considers a target neutral. NPCs usually won't consider these targets at all, or at least not care about them as enemies or as allies. This is used for fauna like crows. Tip:Making a npc_citizen neutral to the player (but not the other way around) is used to prevent them from joining the player's squad.
Error (D_ER)	This "error" disposition is used internally to determine if something went wrong in a relationship. Should not be used. NPC behavior mostly equivalent to neutral.[confirm]

Flags

Notify subject of target's location : [1]

Notify target of subject's location : [2]

Keyvalues

Name (targetname) <string>[ Edit ]

The name that other entities refer to this entity by, via Inputs/Outputs or other keyvalues (e.g. parentname or target).
Also displayed in Hammer's 2D views and Entity Report.

See also:  Generic Keyvalues, Inputs and Outputs available to all entities

Subject(s) (subject) <target_name_or_class>

The targetname or classname of the NPCs whose disposition will change.

Subject Class (subjectclass) <classname> (in all games since )

As above, for classnames only.

Target(s) (target) <target_name_or_class>

The targetname or class name of the NPCs about whom the subject(s) will change their disposition towards.

Tip:Use !player for the player.

Target Class (targetclass) <classname> (in all games since )

As above, for classnames only.

Disposition (disposition) <choices>

The way the subject(s) should feel about the target(s)

1. Hate
2. Fear
3. Like
4. Neutral

Radius for subject (radius) <float>

Only NPCs within this distance of the entity will have their dispositions changed.

Disposition Priority (rank) <integer>

How much the subject(s) should Like/Hate/Fear the target(s). Higher priority = stronger feeling.

Start Active (StartActive) <boolean>

Apply this relationship as soon as the entity spawns?

Bug:Doesn't work after level transition.  (tested in: )

Reciprocal (Reciprocal) <boolean>

Make the new disposition apply to the targets as well as the subjects.

Inputs

ApplyRelationship

Applies relationship changes. This will change all subject entities' relationships to all target entities.

Note:Once you fire ApplyRelationship, the entity is on until you send a RevertRelationship or RevertToDefaultRelationship input. During the time any entities that spawn who match the subject or target names will be affected.

Warning:Unpredictable results may occur when two ai_relationship entities refer to the same set or subset of target or subject entities. This situation should be avoided.

RevertRelationship

Reverts relationship changes to what the relationship of the first one was at the time the ApplyRelationship input was called (or when this ai_relationship was spawned if Start Active is set).

RevertToDefaultRelationship

Reverts relationship changes to the entities' default relationships, completely returning control of affected relationships to the code.

See also

• List of default AI relationships