This article explains the mechanics of enemy pathing in Arknights.
Overview[]
As with in other tower defense games, enemies in Arknights follow a specific path to enter the objective. However, most maps in Arknights are non-linear and contain multiple paths which enemies could take to reach the objective, in addition to featuring a wide variety of enemies with their own properties, notably aerial enemies. As such, the pathing mechanic in Arknights are not as simple as in other tower defense games.
An enemy's pathing is usually, but not always, consists of two actions: move and stop.
- Move: Self-explanatory; the enemy moves from a starting point (where they spawn, right in the center of the tile where they spawn in) to the ending point (usually the Protection Objective, which is denoted by a very small radius centered on said location). The game uses two parameters to decide how the enemy would take the path from the starting point to the ending point; once the parameters are determined, the SPFA algorithm is used to decide the enemy's current ending point:
Position
, which is the coordinate of the ending point.ReachOffset
, which is a coordinate that determines the offset of the ending point and affects the offset of the route the enemy will take. UsuallyReachOffset
is set to 0, which have no effect, but sometimes this parameter is used to make the enemy walk through Roadblocks.
- Stop: The enemy stays at a certain position for a period of time (in seconds).
Usually an enemy's path will be shown by a red line (yellow line for drones) trailing from their spawn point to their destination when the enemy is about to be spawned (or start moving if the enemy is pre-spawned). This triggers a "wave," which causes Allied Operators to use a voice line in response. In some operations with pre-spawned enemies, if these enemies are killed before they start moving, the red line will still be shown as the stop timer is about to expire. Additionally, most enemies may not spawn until after the previous wave has been killed, easily observable in WD-EX-8, where the last five enemies do not spawn until the Pursuer is dead, and some waves have a set timeout, wherein they will spawn after the previous wave has been killed or their timer has run out.
Enemies generally spawn from Incursion Points and its aerial counterpart, but there are several exceptions:
- Airborne Soldiers, Guerrilla Siegebreakers, and Ursus Assault Crossbowmen spawns by airdropping themselves at certain tiles on the map instead of appearing from Incursion Points. Because of this, they usually do not show their path before spawning.
- Sometimes enemy drones will spawn from outside the map instead of Aerial Incursion Points. This can be easily observed in Sponsor Drones.
- On certain occasions, notably DM-MO-1 and R8-8, an Incursion Point is present, but no enemies will spawn from there.
- In DM-MO-1, this is to justify the "stealthy" entrance of the Sarkaz enemies that appear close to it and warn the player as to the presence of enemies in this area.
- In R8-8, this is because all ground enemies airdrop themselves, and the Incursion Point exists solely as Talulah, the Fighter's exit point.
With the exception of certain enemies such as Sponsor Drones, all enemies are always programmed to enter (and only enter) the Protection Objective that acts as their ending point, thus they will pass through any other Protection Objectives without entering it if one is in their path, which can be easily noticed in CB-EX8. An exception to this is the Sarkaz Lancers in DM-3, whose ending point is set to a hole; if they are somehow shifted into the nearby Protection Objective, they will not enter it and continue moving into the hole. However, the red line path indicator instead claims they will access the Protection Objective.
Certain enemies are programmed to "despawn" instead of heading into the Protection Objective, in which their ending points are set to a location other than the Protection Objective; should the enemy reach its ending point, it will be removed from the map and will be counted in the number of enemies "defeated", but do not deduct the player's LP. Examples include:
- A Rioter in GT-1 will despawn by entering the Incursion Point it spawns from, unless it is killed first.
- Sponsor Drones, Luxury Sponsor Drones, and Cheering Sponsor Drones have their ending point set to outside the map and will despawn once they reach it.
- Emperor's Blades in R8-11 will head to the tile in front of the Incursion Point they are spawned from and will despawn by heading into it after about 30 seconds.
In Episode 08, Talulah, the Fighter' is introduced, and despite being technically considered an enemy unit, her starting point is set to a Protection Objective and her ending point is set to an Incursion Point; she is considered to have been despawned once she reaches the Incursion Point. A LP is deducted if Talulah dies, but not if she enters the Incursion Point. This also applies to Ursus Civilians.
If an enemy's path is obstructed by a Roadblock or Static Roadblock, that enemy will adopt a "Return" command in which it will move through the nearest unblocked terrain towards its ending point, overriding its original movement paths. The only exception to this is if a Roadblock is deployed right on the enemy's position while it already occupies the Roadblock's tile or it is deliberately scripted to move through Roadblocks in certain operations, such as AF-7 or Abandoned Mine, in which case the enemy will follow the programmed path and attack the Roadblock(s) in its way; enemies who have no attack such as Sarkaz Guerrilla Casters, however, will be "blocked" by the Roadblock without destroying it, which also applies to Ursus Civilians on Static Roadblocks. There is a third exception to this possibility, on operations where the enemy pathing has checkpoints which the enemies must hit before continuing their path, as easily observed in CB-EX2, where the enemies will have to go through each four corners of the map before leaving through a Protection Objective; despite being able to place Roadblocks to obstruct these paths, as this does not technically seals "all" exit paths, the enemies will begin attacking them.
Static objects also obstruct the enemy's path in a similar way to Roadblocks, but if the enemy is somehow blocked by one (which is possible if the enemy is shifted towards one and the object possesses a block count), they will attack the object, but will never destroy it since most static objects are invulnerable, until they are killed or moved out of the object's way. The only exception to this is Stun Generators; once they are used, causing the Generator to self-destruct, enemies will be able to move through the tile it formerly occupied.