Alien Entity Behavior – Arma 3

The information on this page could be considered a spoiler for the "First Contact" campaign

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Overview

The small Alien Entity (AE - referred to as Drone in technical systems) is used by ET for surveillance, reconnaissance, research, and defense as needed. It is made from unknown and supremely tough materials. The entity has local control of gravity, and it moves in pulses. It can collect and utilize almost any type of matter from the local environment. The AE appears to communicate on the broad electromagnetic spectrum.

Around its central solid hull, the entity can hold one or more modules in its orbit. These do not themselves have propulsion, so they cannot move out of the entity's sphere of influence. Various types of module exist:

1. Scan Module: used to inspect nearby objects and materials
2. Gravity Tool Module: used to process and launch collected matter in two lethal modes:
   1. Matter Shot: a precise single shot of matter
   2. Matter Burst: a multi-round burst of matter
3. Matter: used to store collected matter as a resource
   1. If it runs out, the entity will collect more from any surface
   2. If it gets dislodged from its orbit, it will fall to the ground and decay (there is some danger to those who get close)

The entity also features several countermeasures:

1. Anti-Projectile System: this can 'catch' and re-direct various slower speed projectiles (it can be overwhelmed)
2. Audiovisual Deception: this uses light and sound to disorient threats
3. Gravity Matter Swarm: this launches a cluster of semi-guided area denial projectiles
4. Gravity Matter Push: this launches matter in all directions as a less-than-lethal defense against nearby threats

At this time there are no known vulnerabilities to Earth weapons, and the entity typically withdraws before any major damage can be inflicted.

Drone

Drone init

After Alien Entity (Small) is placed on the map, you need to execute following functions before you get your drone fully operational.

Setting movement grid

Drone is only able to move in generated grid. It can be generated on fly via bin_fnc_setObjectGrid or by using movement grid module.

Syntax:

ⓘ

[drone, position, cellSizeX, cellSizeY, cellSizeZ, resolutionX, resolutionY, resolutionZ] call bin_fnc_setObjectGrid;

Parameters:

• drone: Object - Object to which grid is attached
• position: Array - PositionATL where drone grid should be created
• cellSizeX (Optional) - Number - size of movement cell in x axis (meters). Default 4
• cellSizeY (Optional) - Number - size of movement cell in y axis (meters). Default 4
• cellSizeZ (Optional) - Number - size of movement cell in z axis (meters). Default 16
• resolutionX (Optional)- Number - number of cells in x axis. Default 20
• resolutionY (Optional) - Number - number of cells in y axis. Default 20
• resolutionZ (Optional) - Number - number of cells in z axis. Default 3

Setting movement properties

The way drone moves can be changed via following function. List of all available movement types is listed in section below

Syntax:

ⓘ

[bin_drone, movementProperties] call bin_fnc_setMoveProperties;

Parameters:

• drone: Object - Object to which movement properties are attached
• movementProperties: String - Name of movement class

Initializing drone scripted sound system

Syntax:

ⓘ

[drone] call bin_fnc_soundDrone;

Parameters:

• drone: Object - Object to which sound system is attached

Initializing drone behavior system

Syntax:

ⓘ

[drone, behaviorType] call bin_fnc_behaviorInit;

Parameters:

• drone: Object - Object to which movement properties are attached
• behaviorType: String - Name of behavior type. Can be either "Drone" or "DroneCombat". Default behavior is "Drone"

Example code

[bin_drone,"Drone"] call bin_fnc_behaviorInit; [bin_drone,"Drone"] call bin_fnc_setMoveProperties; [bin_drone,position bin_drone,nil,nil,nil,5,5,3] call bin_fnc_setObjectGrid; [bin_drone] call bin_fnc_soundDrone;

Switching behaviors

Behaviors listed below can be used with bin_fnc_setBehavior & bin_fnc_setBehaviorCoef.

bin_fnc_setBehavior is using following syntax:

ⓘ

[drone, behaviorName,parameters,terminate,interrupt] call bin_fnc_setBehavior;

Parameters:

• drone: Object - Object to which movement properties are attached
• behaviorName: String - Name of behavior type. Can be either "Drone" or "DroneCombat". Default behavior is "Drone"
• parameters (Optional): Array - Optional parameters which can be passed to behavior. Default empty array
• terminate (Optional): Boolean - If true, currently executed behavior will be terminated and new one will be executed right after termination of existing one is completed. Default false
• interrupt (Optional): Boolean - Determines if behavior should terminated immediately. In case of i.e. research behavior it means that instead of gently putting back scanned object, it will be dropped on ground right away. Default false

Example:

List of available behaviors

Name	Description	Available parameters
Patrol	Drone will move around looking for enemy contacts
Investigate	Drone will look at nearest unit	0: target (Optional): Object - object at which Drone will look at
GravityCannon	If combat modules are present, Drone will use them to engage either random nearby target or	0: target (Optional): Object - target for gravity cannon 1: weapon (Optional): String - can be GravityShotgun_01, GravityCannon_01 or GravityCannon_01_Precise
MissileSwarm	Drone will use area of effect weapon releasing 5 missile like projectiles at nearby targets
Jump	Drone will perform jump to specified location	0: position - Array or String - PositionATL - position to move. If string is provided, Drone will jump to precalculated grid located in provided file. 1: charge (Optional) - Boolean - optional parameters controling if drone should be charging power before making jump. Default false. 2: fast (Optional) - drone will jump up straight away if it's set to true, default false. If number is provided, drone will pick fast jump if distance is above that value.
Avoid	Drone will try to avoid contact with nearby units by moving away from them
Research	Drone will perform research behavior on nearby objects	0: target (Optional) - Object - target to scan. If not specified drone will try to pick some random object in available grid. 1: endless (Optional) - Boolean - research will be performed till it's interrupted by script
Light	Drone will use light burst weapon and try to move away from incoming fire
GravityBurst	Drone will use gravity burst when units are nearby
CollectMatter	Drone will collect 4 matter balls which serves as gravity cannon magazines
Reposition	Drone will move 100 meters away from incoming fire

Scripted Event Handlers

Name	Output	Description
behaviorStarted	0: Object 1: Behavior name	Triggers when new behavior FSM is triggered
behaviorCompleted	0: Object 1: Behavior name	Triggers when new behavior FSM is completed. It will be also fired when behavior was interrupted!

Example code: Drone_EH = [missionnamespace, "behaviorCompleted", { params["_object","_behavior"]; systemChat format["Object: %1, Behavior: %2",_object,_behavior]; }] call bis_fnc_addScriptedEventHandler;

Editing move properties

Movement properties can be modified with in game editor. In order to access it, type following code in console & execute it

ⓘ

call bin_fnc_bezierEditor

You can add points to that graph by double clicking on middle area. It's possible to move those points once they are created. When you are are ready, press "Copy" button and paste result to your config. It's not possible right now to read those values from mission files at the moment.

 	class Movement
 	{
 		class Templates
 		{
 			#define CURVE		<nowiki>{{0,0,0},{0.3,0.9,0},{0.5,0.9,0},{0.5,1.070,0},{0.5,1,0}}</nowiki>
 			#define CURVE_LONG	<nowiki>{{0,0,0},{0.3,0.9,0},{0.5,0.9,0},{0.5,1.024,0},{0.5,1,0}}</nowiki>
 			#define CURVE_END	<nowiki>{{0,0,0},{0.5,1,0},{0.7,1,0},{1,1,0}}</nowiki>
 			#define CURVE_ROT	<nowiki>{{0,0,0},{0,2,0},{0.9,1,0},{1,1,0}}</nowiki>
 
 			class Default
 			{
 				speed = 8; // Average travel speed in m/s
 				pulseDistance = 100; // Distance between pulses
 				maxPulseDistanceFar = 100; // Maximum distance between pulses in long-distance travel
 				maxPulseDistanceClose = 3; // Maximum distance between pulses in short-distance travel
 				altitude = 100; // Altitude above terrain level for long jumps
 				curve[] = <nowiki>{{0,0},{1,1}}</nowiki>; // Movement curve
 				curveEnd[] = <nowiki>{{0,0},{1,1}}</nowiki>; // Movement curve on the last waypoint (smoother settle-in)
 				curveRotation[] = <nowiki>{{0,0,0},{1,0,0},{0,1,0},{1,1,0}}</nowiki>;
 			};
 			class Drone: Default
 			{
 				speed = 7;
 				curve[] = CURVE;
 				curveEnd[] = CURVE_END;
 				curveRotation[] = CURVE_ROT;
 			};
 			class Drone_Intro3: Drone
 			{
 				speed = 12;
 				pulseDistance = 550;
 				maxPulseDistanceFar = 550;
 			};
 			class Drone_Long: Drone
 			{
 				speed = 14;
 				pulseDistance = 250;
 				maxPulseDistanceFar = 550;
 				curve[] = CURVE_LONG;
 			};
 			class CombatDrone: Default
 			{
 				speed = 14;
 				maxPulseDistanceFar = 40;
 				curve[] = CURVE;
 				curveEnd[] = CURVE_END;
 				curveRotation[] = CURVE_ROT;
 			};
 			class CombatDrone_Fast: Default
 			{
 				speed = 28;
 				maxPulseDistanceFar = 40;
 				curve[] = CURVE;
 				curveEnd[] = CURVE_END;
 				curveRotation[] = CURVE_ROT;
 			};
 			class CombatDrone_Long: Default
 			{
 				speed = 28;
 				pulseDistance = 500;
 				maxPulseDistanceFar = 1000;
 				curve[] = CURVE_LONG;
 				curveEnd[] = CURVE_END;
 				curveRotation[] = CURVE_ROT;
 			};
 			class ModularShip: Default
 			{
 				speed = 2;
 				curve[] = CURVE;
 				curveEnd[] = CURVE_END;
 				curveRotation[] = CURVE_ROT;
 			};
 		};

Located in a3\Functions_F_Contact\cfgContact.hpp

Handy commands list

Command	Description	Notes
bin_drone setVariable ["#bD",1];	Set danger level on drone. Danger goes from 0 (no danger) to 1 (maximum danger)
bin_drone setVariable ["#bState","Combat"]	Sets drone behavior to selected state. Currently supported modes are "Safe" & "Combat"
bin_drone setVariable ["#bTarget",player];	Set target for drone gravity cannon
[west,0] call bin_fnc_setTargetWeight - all units from side "west" will be ignored by targeting system [player,10] call bin_fnc_setTargetWeight - Increase player chance of being targeted by drone weapons [bis_car,0] call bin_fnc_setTargetWeight - Vehicle & it's crew will be ignored by targeting system	Coef to target priority - set to 0 to basically exclude drone from target selection. Function accepts group, side, vehicle or unit.	Applied to individual unit, side or vehicle - not the drone!
[bin_drone,"gravitycannon",[cursorObject,"GravityShotgun_01"]] call bin_fnc_setBehavior	Forces drone to target specific object
[bin_drone,"gravityCannon",10] call bin_fnc_setBehaviorCoef;	Change probability of picking specific behavior
[bin_module_01,player,"GravityCannon_01_Precise",false,1] call bin_fnc_setDroneModuleTarget;	Targets & fires module at player	Parameters: 0: Module (Object) - Module which should fire 1: Target (Object or Position) - Object or Position where module should aim at 2: Weapon (String) - Name of weapon which module should use. Can be GravityShotgun_01, GravityCannon_01 or GravityCannon_01_Precise 3: Use Charging (Bool) [Optional]- Define if charging of module should be skipped. Default true 4: Timeout delay (Number) [Optional] - Default 1 second
[bin_drone,"SwarmMissile_01_launcher_F"] call bis_fnc_fire;	Manually trigger missile swarm

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Modules

Setting up modules

Creating module

In order to create module use following function. You don't need to place drone module on map itself!

Syntax: _module = [drone, moduleClassName, moduleType] call bin_fnc_initDroneModule;

Parameters:

• drone: Object - Parent object to which modules are attached
• movementProperties: String - Class name of vehicle to create. List of available module is available below
• moduleType: String type of module to register - currently "combat", "matter" & "science" are available.

List of available modules

Class name	Name	Picture
Alien_MatterBall_01_F	Matter Ball
B_A_AlienDrone_Module_01_F O_A_AlienDrone_Module_01_F I_A_AlienDrone_Module_01_F	Scan Module (can be used to perform research operations)
B_A_AlienDrone_Module_02_F O_A_AlienDrone_Module_02_F I_A_AlienDrone_Module_02_F	Gravity Tool Module (can be used in combat)

I, B, O are abbreviation for factions - I = Independent, B - Blufor, O - Opfor

Module variables

Name	Variable	Notes
Interval	bin_droneModule_interval	Sets how strictly module is following the drone. 0 means it's basically out of control where 1
Radius	bin_droneModule_radius	Radius of module orbit (calculated from Drone center)
Height	bin_droneModule_height	Height offset of the module orbit (calculated from Drone center)
Rotational speed	bin_droneModule_rotationTime	How much time it takes to perform one full rotation
Damage	bin_droneModule_damage	By default, modules damage is synced to damage status of parent vehicle. With this variable it's possible to override this behavior and either enable or disable damage completely.

Example

_module_1 = [BIN_drone,"I_A_AlienDrone_Module_02_F ","combat"] call bin_fnc_initDroneModule;
_module_1 setVariable ["bin_droneModule_interval", 0.75]; 
_module_1 setVariable ["bin_droneModule_radius", 4.28683];
_module_1 setVariable ["bin_droneModule_height", 1.5];
_module_1 setVariable ["bin_droneModule_rotationTime", 6.5];