ai_sound

ai_sound is an e0 available in all Source games. This entity makes abstract sounds or smells that can be sensed by NPCs, but not by the player. This can be used to cause reactions in nearby NPCs. An entity called soundent appears to help with managing AI sounds when the game runs.

In code, it is represented by theCAISoundclass, defined in thesoundent.cppfile.

Keyvalues

Volume (volume) ([todo internal name (i)]) <integer>

How far away this sound can be heard. This is a radius.

Duration (duration) ([todo internal name (i)]) <float>

How long the sound persists each time it plays.

Sound Type (soundtype) ([todo internal name (i)]) <choices>

The type of sound or smell will determine the reaction of NPCs that sense it. Some of these are not in the FGD, so their associated number must be typed manually.

Literal Value	Description
1	Combat: Will cause most NPCs to become alert
2	World: Will cause most NPCs to become alert
4	Player: Feign player audible
8	Danger: Will cause most NPCs to move away from the position of the sound
16	Bullet Impact
32	Carcass
64	Meat
128	Garbage
256	Thumper: causes antlions to run away briefly
512	!FGD Bugbait: get nearby antlions' attention
1024	!FGD Physics Danger: Scares off npc_metropolice, npc_combine_s, and npc_antlion
2048	!FGD Sniper Danger: Scares npc_snipers into their hole
4096	Move Away: Pushes away npc_metropolice, npc_citizen, npc_combine_s, npc_alyx, npc_barney, npc_fisherman
8192	!FGD Player Vehicle: Makes NPCs hear the player & makes npc_metropolice turn towards the sound (only used by prop_vehicle_airboat
16384	Player Companion Readiness: Low
32768	Player Companion Readiness: Medium
65536	Player Companion Readiness: High

Additional sound context (optional) (soundcontext) ([todo internal name (i)]) <choices>

Optional settings specifying such things as who can or cannot hear the sound. Many of these are not in the FGD and some of them have not been fully tested.

Literal Value	Description
1048576	!FGD Sound is from Sniper
2097152	!FGD Gunfire (use with combat sound type)
4194304	!FGD Mortar (pending explosion)
8388608	Only Combine hear/smell
16777216	!FGD React to source (faces the ai_sound instead of location proxy)
33554432	!FGD Explosion (use with combat sound type)
67108864	Exclude Combine (Combine don't hear/smell)
134217728	!FGD Danger approach (react with danger if you see the ai_sound, just face if otherwise, shouldn't work with location proxy)
268435456	!FGD Only allies (npc_citizen, etc.) hear/smell

Location Proxy (locationproxy) ([todo internal name (i)]) <targetname>

If you specify an entity here, the sound will be made at that entity's location (!player is an option).

Inputs

InsertSound <integerRedirectInput/integer> 

Deprecated.
Insert a sound in the AI sound list at a specified volume (1-100) which influences detection radius.

EmitAISound

Make the Sound.