Where SI Spawn From: The 250-Unit Hard Exclusion and Class Distance Bands

Safety first, scoring second

Spawn points are not random. The extension pulls walkable spots from the directed Nav graph, then filters: Nav flags, flow position, local density, stuck, visibility, real path. Failures are not scored.

Survivors of the filter are scored on distance, height, Flow, spread, and class habits. Pick the best one now.

The 250-unit straight-line hard exclusion

Under 250 units from any survivor, the spot is dumped. That is 3D straight-line distance. Nav detours do not help. Point-blank spawns do not exist. If it feels in your face, it left a legal roof or corner and closed immediately.

Class distance bands

Distance is the directed path from candidate Nav to target Nav. Each class searches its closer preferred band first. On failure only the far cap widens. The class minimum does not move.

Why they are always above you

Smoker and Hunter get a high-ground cut. Once a candidate is 32 units above eye level, extra height is subtracted from Nav distance at 1.5x for Smoker (cap 1000) and 1.15x for Hunter (cap 800). Long roof detours can still score.

The cut only changes the cap and the score. The 250 hard exclusion stays. The class minimum stays.

Some things people say, and whether they hold

"The server spawns them right on top of you"

Does not hold. The 250-unit rule is a hard exclusion on straight-line 3D distance; points that fail it never reach scoring at all. What you see is a special leaping at you immediately after emerging from a legal point — a Hunter at the extreme tier has an air speed of 900 and covers that distance in under a second.

"Turning off your flashlight stops them spawning"

Does not hold. Visibility is only one scoring factor, and it has nothing to do with your flashlight.

"Stand in a corner and nothing can spawn behind you"

Partly true. Places with less walkable area really do have fewer candidate points, so backing against a wall helps. But if there is a passage on the other side of that wall, it is still legal ground.

"Run fast enough and you outrun the spawns"

Does not hold, and it hurts. Progress uses the team's lower-median flow, so running alone neither resets the countdown nor keeps you out of the isolation check.

"Specials always come from behind"

That is observation bias. You see the ones in front and deal with them early; the ones behind you did not see, so they stick in memory. The real pattern is that they come from whichever direction has more walkable area.

How terrain changes where attacks come from

Once you know the rules you can read terrain backwards: which places have many spawn points and which have few, so your positioning is informed.

• A long straight corridor：The two ends are the only legal directions; the middle is mostly excluded by the 250 rule. So in a corridor they almost always come from front or back — watch both ends and that is enough.
• A multi-storey building：The high-ground discount makes it easier for Smokers and Hunters to enter from above. Look up when you go into one.
• An open plaza：Legal points in every direction — the hardest terrain to hold. Do not linger in the middle; hug one side.
• Rooms inside rooms：The next room over often lands squarely in the Boomer's preferred 250–550 band. Think about that before you open a door.
• Bridge decks and rooftop edges：One side is empty air, so usable spawn points concentrate on the other. Easier to hold than it looks.

In play you do not need exact distances. One rule is enough: the more walkable ground, the more places they can spawn. Move toward less walkable space and the directions of attack narrow on their own.

Practical takeaways

• Boomer preferred band is the closest, 250 to 550. Treat doors and corners as occupied.
• Smoker minimum is 500. It will not spawn on top of you. Tongues mostly come from mid-to-long range or above.
• Camp one room and nearby legal spots get reused. Move, and the attack direction changes.

See each map's Nav spawn points in the spawn visualizer