Areas are oblong-shaped collision zones which can trigger callbacks when the player or other objects enter them; they are also often used as position markers for things spawned in code such as sounds or particle effects.

HPL3 ships with several different area types - here's a quick summary of them and of some of their properties.

The most commonly used type of area, used for all sorts of purposes.

If true, this area acts as a blocker for AI seeing the player.

Collision callbacks - for example, if you set CC_Entities to player and CC_Funcs to TriggerHitArea then TriggerHitArea will be called in your map script whenever the player enters or leaves the area.

Called when the player has the area on-screen. Various other properties in the same section modify exactly when that happens.

Makes the area interactable, and triggers this callback when the player interacts with it. You can also set CustomInteractIcon etc.

The player, by default, casts a small point light around him so that you can see things even when the room is very dark. This area type changes that ambient light to fit the current area.

Indoors / Outdoors / None

Used as a camera viewpoint in a camera animation. See Camera Animation.

This area becomes interactable; when you interact, you will climb up to a specified foot position. It's used for things like climbing into vent shafts or climbing up on to a nearby table or something; for higher climbs, you probably want a camera animation or a ladder instead.

Name of an entity (usually a trigger area) specifying where the feet should land after the climb.

Specify if the player should be automatically crouched after the climb (useful for vent shafts).

The player will be crawling on their belly while in this area, and can't run or stand up. Useful for vent shafts.

The player can interact with this area as if it were a datamine prop - see Datamine

Currently unused.

Used with the Description module. Not used in SOMA.

This area will apply a Distortion Effect to the player while they are in it.

This area is really useful for telling you when the player has walked into a particular part of the map. You set up a doorway with the Z-axis pointing in to the 'inside' and away from the 'outside'. Now when the player walks in through the door, the DoorwayCallback is called with an alState parameter of 1. When the player walks out through the door, the callback is called with an alState of -1.

You can also link sets of doorways, which is a great way to figure out if the player is inside an irregular space. If you specify the DoorwayGroup property, then you can use the function Doorway_PlayerIsInGroup to check if the player has crossed into the space delimited by these doorways. (Essentially, if you cross any of the doorways going 'inwards' so alState==1, then you are in the group; crossing any going 'outwards' so alState==-1 means you are outside the group).

This acts just like CC_Entities on an area - it just specifies which entity to check for collisions with. This is usually player.

Called when the DoorwayEntity goes in or out of the doorway.