[Klonan] [2.1.12] Biter wander area is off‐center from spawner

secelt · Post by **secelt** » Sun Aug 02, 2026 7:23 pm

TLDR: the area in which an idle biter wanders is centered on its spawn point, not its spawner.

introduction

for my 2.1 playthrough, i decided to go for the “Keeping your hands clean” achievement, especially since, now that it isn’t cheesable by blocking the spawners’ spawn points, it’s much more rewarding to accomplish. i had a few failed runs at first: i would always surround the spawners with turrets and leave the minimum amount of space to not block their spawning, which made the spawned biters immediately attack the turrets on sight, causing a constant ammo drain on my resources, which eventually doomed me to being overwhelmed.

i then decided to take a look at the biters and spawners’ prototypes to try to figure out what i was doing wrong. i eventually found out that biters will attack any military target as soon as it comes within 30 m of them (or vice versa). my plan at this point was to keep the turrets far enough away from the spawners to ensure that no biter will see them while idly wandering around.

after some experimentation, i figured out that biters will try to stay within a circular disc of radius ~10 m from their spawn point when wandering, which is always the top‐leftmost (north‐westernmost) spawn point possible. this is a bit inconvenient, since it means that the biters’ wander radii are always offset from their spawners by 4 tiles north and west, which, in turn, offsets my defenses by the same vector.

i still haven’t found how the game calculates this “wander radius” from the prototype data and if it’s hard‐coded or not. i’d love some insight into this if possible, please!

reproduction

place a spawner in a test world with enemy expansion disabled.
let it spawn a few biters and notice that they always spawn in the top‐leftmost corner of the spawn area.
fast‐forward the simulation and notice that the biters stay within a circle centered on their spawn point on the top‐left of their spawner.

i expected the biters’ wander area to be centered on their spawner, not their spawn point.

here’s a screenshot and blueprint of a guide/template i used when creating my defenses:

: blueprint screenshot; Screenshot_20260802_151045.png (61.8 KiB) Viewed 274 times

i’ve attached my save file and log file.