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.
This marks of a specific area as somewhere that the player can hide i.e. they will no longer be visible to AI. This is not used in SOMA, but can work regardless.
This is used to expand the interaction area of another entity such as a prop; so that you can, for example, give a small button a bigger interact area. For all purposes, interacting with the area is treated as if you're interacting with the prop itself. If you set interaction disabled on the prop, the area will deactivate too.
The entity to interact with.
This is used to allow the player to climb ladders. Position the ladder area up the ladder prop. Note that in SOMA rungs have to be 0.5 units apart, and the ladder area itself has to be a multiple of 0.5 units tall and aligned to the rungs for the animation to work properly.
Use these to specify an area to move to when you step off the top of the ladder (usually a Trigger area).
Use these to specify an area to move to when you step off the bottom of the ladder (usually a Trigger area).
Creates an area of liquid - useful for pools of water or for use in SOMA's airlocks. You can control waves, surface colors, fog under water etc. - properties should be reasonably self-explanatory.
Map Transfer areas are used in map transitions; anything within a Map Transfer area is preserved as the next map is loaded. See Map Streaming.
Pathnodes are points rather than areas; they are used in AI for the pathfinding system.
Player Start areas are where the player will appear as the result of a map load (by default, the player appears at PlayerStartArea_1, although that can be changed) or as the result of a Player_Teleport() call.
Specifies whether the player should be crouching when they appear at that spot.
Not used in SOMA.
Not used in SOMA.
Sit areas specify an area that the player can interact with to sit down.
Soundscape areas are used to set up the ambient sound for particular areas. You'd generally have one soundscape area for every room. See Soundscape Area for more details.
Sticky areas are used to attach other entities to (normally Prop_Grab) - when the entities are pulled away, there'll be resistance, and if you don't pull hard enough they'll snap back. This is used to implement things like pulling power cables from sockets or attaching cables to sockets.
Name or names of bodies that can be attached to this area. Accepts wildcards.
If true then the connected body can be detached.
If true then bodies will only detach or attach if the player is actually interacting with them (as opposed to e.g. walking into an object to knock it free).
Whether to orient the body to the attach position.
Called when an entity is attached to this area.
Called when an entity is detached from this area.
Use these to give some resistance to the detachment or attachment - so that the attach area 'sucks in' the body.
If the player walks into a tool area and has the specified tool in their inventory, then it will automatically be equipped (i.e. brought out and shown on screen in their hands). This is what is used for showing the Omnitool next to an airlock control panel.
A list of tools to bring out when in this area.
Other tool areas that are part of the same group; this is to make it easy to set up irregularly shaped tool areas by combining multiple rectangular areas.
Specify a look entity, and the tool will only be brought out if the player is facing that entity. In most cases, it would be the object that they can interact with e.g. the airlock panel. This is used so that the tool isn't brought out if the player backs in to a tool area.
This area type repels AI creatures who enter it.
Specifies a particular point (usually a TriggerArea) to head towards if the agent enters this area.
The visibility area is used to divide a map into areas that should not be visible at the same time. This helps the engine cull objects that are outside of the view and should not be visible. Adding viability areas to the map will increase performance since it will give the engine an easier time partitioning the objects. It is also possible to manually disable a visibility area, this will hide all the objects that are inside it. An object will be part of all visibility areas that it is fully inside of.
Objects that doesn't fit inside any of the placed areas will get added to a main render container that has an infinite size.
Visibility areas should be placed around large rooms, floors or large outdoor zones. They should be placed so that when you are inside one of the areas the other areas are not visible because it is occluded by geometry (like floors or walls). If a map has multiple floors