Ai goal follow

ai_goal_follow is a point entity available in all Source games. It makes the target NPCs follow another object or the player at a configurable distance. NPCs may react in some way if they can't path to their leader.

 Note: NPCs do not intelligently follow their leader. They will simply walk or run depending on distance directly towards it. If the followers happen to block a path, they will not move out of the way and the leading NPC will eventually give up trying to path. (Depends on Formation.)

This entity is not in .

In code, it is represented by class CAI_FollowGoal, defined in ai_behavior_follow.cpp.

ConVars/Commands

ConVar/Command	Parameters or default value	Descriptor	Effect
ai_debug_follow	0	0 disables, 1 enables	Tells when an NPC is having trouble following their leader. Requires developer 1. Does not function. [confirm]
ai_follow_use_points	1	0 disables, 1 enables	To do: Effect description.
ai_follow_use_points_when_moving	1	0 disables, 1 enables	To do: Effect description.

Keyvalues

Target Entity (goal) <string>

The name of the entity that the NPCs should follow. If this value is blank, NPCs will follow the player, if they are friendly towards them.

Formation (Formation) <choices>

How close to the target the NPCs should follow.

• 0: Close circle
• 1: Medium Circle
• 2: Wide circle
• 3: Sidekick
• 4: Vortigaunt

To do: What exactly do 3 and 4 do? AI_GoalEntity:

Actor(s) to affect (actor) <target_name_or_class>

The targetname or classname of any NPCs that will be included in this goal. Wildcards are supported.

Search Type (SearchType) <choices>

What the Actor(s) to affect keyvalue targets by.

• 0: Entity Name
• 1: Classname

Start Active (StartActive) <boolean>

Set if goal should be active immediately.

Base:

Classname (classname) <string>

The classname defines the type of entity. Classnames can be changed using AddOutput, which will influence how the engine deals with the entity in certain circumstances.

Name (targetname) <string>

The name that other entities refer to this entity by.

Global Entity Name (globalname) <string>

Name by which this entity is linked to another entity in a different map. When the player transitions to a new map, entities in the new map with globalnames matching entities in the previous map will have the previous map's state copied over their state.

Parent (parentname) <targetname>

Specifies a movement parent. An entity will maintain its initial offset from its parent. An attachment point can be added to the end of the name, separated by a comma. Every entity can be parented, even point entities. Entities which are parented will be forced to transition to the next map, such as from a trigger_transition. Some entities which aren't intended to be parented may not function correctly. phys_constraint can be used as a workaround to parenting.

Origin (X Y Z) (origin) <coordinates>

The position of this entity's center in the world. Rotating entities typically rotate around their origin.

Pitch Yaw Roll (X Y Z) (angles) <angle>

This entity's orientation in the world. Pitch is rotation around the Y axis, yaw is the rotation around the Z axis, roll is the rotation around the X axis.

 Note: This works on brush entities, although Hammer doesn't show the new angles.

Flags (spawnflags) <integer>

Toggles features of an entity, its specific number is determined by the combination of flags added.

Response Contexts (ResponseContext) <string>

Pre-defined response system contexts for this entity. Format is key:value,key:value,.... Contexts may be filtered.

Effects (effects) <integer> !FGD

Combination of effect flags to use.

Local Time (ltime) <float> !FGD

The local time of the entity, independent of the global clock. Used mainly for physics calculations.

Next Think (nextthink) <float> !FGD

Amount of time before the entity thinks again.

Hammer ID (hammerid) <integer> !FGD

The entity's Hammer ID. Mainly used by plugins and debugging commands, such as ent_keyvalue. Can be manually assigned with the "hammerid" or "id" keyvalue. Entities spawned at run-time are not assigned any Hammer ID.

Disable for Xbox 360 (disableX360) <boolean> (in all games since ) !FGD

If Yes, disables this entity on the Xbox 360 version of Source.

Entity Scripts (vscripts) <scriptlist> (in all games since )

Space delimited list of VScript files (without file extension) that are executed after all entities have spawned. The scripts are all executed in the same script scope, later ones overwriting any identical variables and functions.

Script think function (thinkfunction) <string> (in all games since )

Name of a function in this entity's script which will be called automatically every 100 milliseconds (ten times a second) for the duration of the script. It can be used to create timers or to simulate autonomous behavior. The return value (if present) will set the time until the next call. Try to avoid expensive operations in this function, as it may cause performance problems.

Lag Compensation (LagCompensate) <boolean> (in all games since ) !FGD

Set to Yes to lag compensate this entity. Should be used very sparingly!

Is Automatic-Aim Target (is_autoaim_target) <boolean> (in all games since ) !FGD

If set to 1, this entity will slow down aiming movement for consoles and joystick controllers when the entity is under the crosshairs.

Inputs

OutsideTransition  (in all games since ) !FGD

Usually this is automatically done by a trigger_transition when the map changes, but it can be done manually as well. It sends the entity into a "dormant" state where it is disabled even though the entity may still think it is active. This is done in the case that the player decides to go back to a previous map, where the entity will then become non-dormant again and ensure NPCs continue to follow. Only available for the HL2 Episodes and Portal.

AI_GoalEntity:

Activate

Make the goal active if it wasn't already. NPCs will begin taking orders.

Deactivate

Make goal inactive.

UpdateActors  !FGD

Tell the goal entity to re-check Actor(s) to affect in case any disappeared, or any new NPCs spawned.^[confirm]

Base:

Kill

Removes this entity and any entities parented to it from the world.

KillHierarchy

Functions the same as Kill, although this entity and any entities parented to it are killed on the same frame, being marginally faster than Kill.

SetParent <string>

Move with this entity. See Entity Hierarchy (parenting).

SetParentAttachment <string>

Change this entity to attach to a specific attachment point on its parent. The entity will teleport so that the position of its root bone matches that of the attachment. Entities must be parented before being sent this input.

SetParentAttachmentMaintainOffset <string>

As above, but without teleporting. The entity retains its position relative to the attachment at the time of the input being received.

ClearParent

Removes this entity from the the movement hierarchy, leaving it free to move independently.

AddOutput <string>

Evaluates a keyvalue/output on this entity.
Format: <key> <value>
Format: <output name> <targetname>:<inputname>:<parameter>:<delay>:<max times to fire, -1 means infinite>

FireUser1 to FireUser4

Fire the OnUser outputs; see User Inputs and Outputs.

Use  !FGD

Same as a player invoking +use; may not do anything. Can also be invoked by creating an output that does not specify an input.
This input is not included in Valve's FGDs.

DispatchEffect <string> (removed in ) !FGD

Dispatches a special effect from the entity's origin. Removed and replaced entirely by the particle system since .

DispatchResponse <string> !FGD

Dispatches a response to the entity. See Response and Concept.

AddContext <string>

Adds to the entity's list of response contexts. Format is <key>:<value>.

RemoveContext <string>

Remove a context from this entity's list. The name should match the key of an existing context.

ClearContext <string>

Removes all contexts from this entity's list.

RunScriptFile <script> (in all games since )

Execute a VScript file from disk, without file extension. The script contents are merged with the script scope of the receiving entity.

RunScriptCode <string> (in all games since )

Execute a string of VScript source code in the scope of the entity receiving the input. String quotation may be needed when fired via console.

 Bug:  In , the code is executed in the script scope of the entity that fires the output, not the one receiving the input.

 Warning: Never try to pass string parameters to a script function with this input. It will corrupt the VMF structure because of the nested quotation marks, which then must be removed manually with a text editor.

CallScriptFunction <string> (in all games since ) !FGD

Execute a VScript function in the scope of the receiving entity.

SetLocalOrigin <coordinates> (in all games since ) !FGD

Send this entity to a spot in the map. If the entity is parented to something, it will be offset from the parent by this amount.

SetLocalAngles <angles> (in all games since ) !FGD

Set this entity's angles.

Outputs

Base:

OnUser1 to OnUser4

These outputs each fire in response to the firing of the like-numbered FireUser1 to FireUser4 Input; see User Inputs and Outputs.