Field Manual // Section 02
Fog Mechanics & the Acoustic Threat Model
The mist is not a filter over the world. It is a second set of physics. Under 60% density the infected hear roughly what you hear; past it, every noise you make is broadcast at up to four times its clear-air radius. This page is the model behind every "stay quiet" instruction in the manual.
Live Mist Scope
SWITCH PHASENoise Radius Calculator
MODELLED OUTPUTEvery action in the game emits a signature. In clear air that signature travels its base distance; in mist it multiplies. The calculator below applies the same multiplier the infected use, then compares the result against the current horde pull radius — the distance at which a noise event summons everything within earshot.
The Three Phases, In Detail
24H CYCLEPhase 01 — Noon Clear
Density sits near zero and the acoustic model collapses back to baseline. Sight distance exceeds 150 metres, which is further than most of the valley is wide. This is the window for anything that requires you to see a target before it sees you: reading deer movement, scouting a raider camp from the ridge, or confirming a route before you commit to it.
The trap is that clear air is also quiet air. A single unsuppressed shot at noon still carries roughly 65 metres, and in open terrain that is a straight line — no ravine walls to absorb it, no fog to muffle it. Clear weather is when you can see the consequences of your own noise arriving.
Phase 02 — Volumetric Mist
Density crosses 42% and the visibility term in the renderer starts eating the far plane. Sight collapses to about 15 metres while the acoustic multiplier steps to 2.5x. The effect is deliberately asymmetric: you lose your eyes long before the infected lose their ears.
Practically, this is the phase where base design matters more than base location. A cabin with a single barrable door and an interior hearth lets you work through the mist; an open compound forces you to guard sightlines you cannot see down. If you hear a screecher during this phase, the correct response is to stop moving, not to move faster.
Phase 03 — Supercell Midnight
This is the phase the manual is written around. Sight drops under five metres and the multiplier reaches 4.0x, which turns a routine action like felling a tree into a 170-metre broadcast. The horde pull radius at this density is the largest in the game.
Two rules survive the supercell. First, extinguish everything that burns — fire is a beacon with a range you cannot calculate. Second, hold a doorway rather than a perimeter; a chokepoint turns a horde into a queue, and a queue is something one breacher with a 12-gauge can actually process. Do not attempt to cross the basin in a supercell. There is no route that is worth it.
Why the fog is volumetric and not a shader trick
Because it caches into system memory, the fog volume is a real object in the scene with a calculable density field. That is what makes the 4x acoustic multiplier legible rather than arbitrary: the same density value that darkens your view is the value the AI samples to decide how far a noise reaches. The numbers on this page and the numbers in the game come from the same variable.
