Idle Motion¶

Overview¶

Idle Motion is fallback steering for agents with low target awareness. It picks a seeded random planar direction, keeps it for a time window, then changes to another direction. Give it a Leash Radius and that drift is tethered: once an agent is further than the radius from its anchor, the direction blends toward home instead of wandering on. Give it a Rest Time and an agent with nothing to chase stops after each walk and stands for a while before it sets off again.

It ships enabled, so an archetype you never touched already has it.

In motion, this makes unfocused agents drift, shuffle, or wander slightly instead of standing perfectly still. It is subtle by default and meant to support believable crowd behavior when agents are not confidently tracking a target.

This behavior contributes polish rather than pressure. It helps the swarm look alive when awareness drops, but it is not a replacement for pursuit or recovery logic.

Parameter Reference¶

Advanced Parameters¶

All parameters here are advanced: leave at defaults unless you have a reason

Idle Motion¶

Visible effect: Low-awareness agents keep moving a little instead of freezing.
Gameplay effect: Makes crowds feel less robotic when idle, far away, or temporarily lost.
Increase when: You want ambient motion or better fallback behavior.
Decrease when: Idle agents should stay planted or behavior should be very explicit.
Pitfalls: On its own, this does not create purpose. It only fills dead air.
Technical effect: Adds the idle-motion pass, scaled by 1 - target awareness, so fully aware agents ignore it. Dormant and surrendered agents are dropped before the awareness math runs, so they never drift no matter how unaware they are. Both of those systems ship on, and that has a consequence: a slow wander often fails the dormancy movement test, which puts the agent to sleep where it stands, and an agent with no target has nothing to wake it. If your idle crowd freezes shortly after it starts wandering (the wait is Dormancy Delay Seconds on the Swarm Settings), that is why. Rest Time is the fix.

Idle Motion Weight¶

Visible effect: Higher values create stronger wandering.
Gameplay effect: More ambient life, but also more drift away from precise positions.
Increase when: Lost or idle agents look too static.
Decrease when: Random drift makes enemies look confused.
Pitfalls: Too high makes agents look drunk or disconnected from the target.
Technical effect: Scales random idle steering when awareness is low.

Direction Change Interval¶

Visible effect: Short intervals look twitchier; long intervals produce longer drifts.
Gameplay effect: Short values feel nervous, long values feel lazy or shambling.
Increase when: You want smoother shambling or subtle idle movement.
Decrease when: You want restless insect-like or panic-like motion.
Pitfalls: Very short intervals can look noisy, especially in a large crowd.
Technical effect: Seconds before the random direction is refreshed.

Rest Time¶

Visible effect: Agents with nothing to chase walk for one Direction Change Interval, stop and stand still for this many seconds, then pick a new direction. At the default 0 they never stop.
Gameplay effect: A lethargic crowd: some shuffling, some standing, never all at once. The zombie town in MSS Zombie City ships walk 4, rest 5.
Increase when: The crowd should look sleepier, or an idle crowd costs more than you want. A resting agent is allowed to go dormant, so longer rests make an idle crowd cheaper.
Decrease when: The crowd should look restless. Leave it at 0 for continuous wandering.
Pitfalls: A rest no longer than the dormancy window (Dormancy Delay Seconds on the Swarm Settings, 0.75 s by default) never gets to sleep, so it costs the same as a crowd that is always awake. Only an agent with no target and no awareness of one rests. An agent that is chasing does not rest, and neither does one that is searching, remembering a target it lost, or still noticing one during its Acquire Time.
Technical effect: While an agent walks it is kept out of the dormancy movement test, so a slow walk no longer puts it to sleep. While it rests it may sleep, and it wakes when the rest runs out. Seeing a target, hearing a noise or being shot still wakes it at once. The cost follows how many agents are asleep at a given moment. A crowd that stays still falls asleep where it stands and costs least. A crowd whose rest is longer than the dormancy window keeps wandering while part of it sleeps, and that costs less than a crowd that is never allowed to sleep.

Timing Jitter¶

Visible effect: Breaks synchronization so agents do not all turn, stop or start walking at once.
Gameplay effect: Makes ambient motion feel less artificial.
Increase when: The crowd updates in visible lockstep.
Decrease when: You want more regular beat-like motion.
Pitfalls: At 0, timing is uniform. At 1, timing variation is wide; combined with high weight it can look chaotic.
Technical effect: Randomizes each walk and each rest around its base value, scaling it between 1 - jitter and 1 + jitter. Walk and rest are drawn separately, so a long walk is not always followed by a long rest. With a Rest Time and jitter 0, agents that stopped chasing at the same moment walk and stop together from then on, and the inspector points it out.

Leash Radius¶

Visible effect: How far an idle agent wanders from its anchor before it starts drifting back. It is not a hard limit: the pull grows from there and is full at twice the radius, so agents are seen past it. At the default 0 there is no limit, so a crowd left idling spreads across the level over time.
Gameplay effect: The difference between a nest or a guarded street that stays populated and one that slowly empties itself while the player is somewhere else.
Increase when: Agents are meant to belong somewhere. Set it to roughly the size of the area they should hold.
Decrease when: Idle agents should be free to roam, or you want the pre-leash behavior back, which is what 0 gives you.
Pitfalls: 0 is the shipped default and the inspector says so with a note, because the unbounded drift it produces is easy to mistake for a bug much later. The anchor starts where the agent spawned and moves every time the agent loses or changes its target, to the spot where it stood at that moment, so a crowd is held where it gave up and is not dragged back to the spawner. With Searching enabled on the Perception Profile the anchor also follows the target while the agent sees it, and a heard noise while the agent walks to it, so during a search the leash pulls toward the last seen spot.
Technical effect: Outside the radius the wander direction is blended toward the anchor, reaching pure homing at twice the radius. The blend is deliberate: switching hard at the boundary makes a crowd hover on the circle and draws a visible ring.

Practical Usage Guidance¶

Use Idle Motion for zombie hordes, shamblers, off-target packs, or any enemy set where low-awareness drift looks better than hard stops.

Give the archetype a Perception Profile or this does nothing to a targeted agent

Awareness only drops below 1 for an agent that carries a Perception Profile. Perception is what writes a decaying value into it once contact breaks, fading over the profile's Forget Time, and an agent that has lost contact keeps that fading value whether it is searching, following an informed neighbour, or doing neither. An archetype with no Perception Profile assigned always reads as fully aware while it holds a target, so idle motion never engages for it. What is left without one is agents with no target at all, or archetypes with Approach & Press switched off and none of Retreat, Predictive Catch-Up or Orbit Style steering them. Assign a Perception Profile to the archetype and the pass starts doing what this page describes once that agent loses contact.

It works well alongside lost-target recovery because leader following can keep some motion going while idle motion fills the gaps when awareness is nearly gone. It is also useful in sample scenes where stationary agents quickly look fake.

Do not lean on this for active combatants. If an enemy should always know where the player is and always push with intent, keep this subtle or disabled.

Three behaviors keep idle motion off for an agent with no Perception Profile

Retreat, Predictive Catch-Up and Orbit Style each write target awareness to 1 on a step where they steer an agent, and each skips an agent that cannot see its assigned target. An agent that has lost contact keeps its fading awareness, so idle motion still engages for it with any of them enabled. The case to know about is an archetype with no Perception Profile: it always counts as seeing its target, so turning on Predictive Catch-Up or Orbit Style keeps idle motion off for as long as the agent holds a target, even with Approach & Press switched off. Retreat does the same only inside its Recover Radius. All three ship disabled, so this only bites once you turn one on.

Gameplay Interpretation¶

This behavior makes enemies feel less mechanically precise. Low values read as subtle shuffling; high values read as confusion or feral motion.

It can make a crowd feel more alive between strong steering beats, but pushed too far it also slightly reduces player readability.

Quickstart: tune in this order

Decide Leash Radius first, because it is the one that changes where a crowd ends up rather than how it looks. Leave it at 0 only if these agents are genuinely free to roam.
Tune Idle Motion Weight. Most of the time that is the only value that needs meaningful adjustment.
Change Direction Change Interval if the movement cadence feels too twitchy or too sleepy. It floors at 0.01 seconds.
Set Rest Time if idle agents should stop now and then, or if they freeze instead of wandering.
Leave Timing Jitter near 0.5 unless you specifically see crowd-wide synchronization.