Crowding out and vacating

## Crowding out

When the number of characters occupying a particular instance of a zone (city) reaches 50, a new instance (called a substitute) of the same zone is created. The substitute accepts newly arriving players until the population of the original (main) instance falls below 50 again. Grouped players arrive at the same instance of a zone their groupmates are in.

If the population of the main instance falls below 50, players entering the zone again only arrive at the main, and the substitute instance is only accessible through forming groups, or recrowding the main. It is possible for a substitute to become the main instance if it survives while the main is abandoned by all players. It is also possible for a higher grade substitute to be created by crowding a substitute instance. When it comes to bosses, missions and passages, substitutes have the same properties vacated instances have (see below).

## Vacating

Vacating occurs when the population of the only instance of a zone falls to 0 (when all players depart from the zone). In that case, for the first player arriving in that zone again, a new instance of the zone is formed, which, relative to the original instance, has:

* a new boss spawned (it may be locked in a secret passage and therefore not immediately available)
* (randomly) different or same side mission characters
* the same or a reversed secret passage open; depending on which zone it is, the time of day and whether the reversing has already happened that hour (after it happens once, any new instances of the zone created during that hour have that same single-reversed passage). But even if opening is the same passage, it will have to be unlocked again (by killing the 100 infected).

## Which passages open in new and vacated instances

 pre-lasers
(straight)
 post-lasers
(crossed)
 lasers hour

* Freezer always forces the Valley column to open. It's easy to remember that Railroads go together, Cars go with the Garage, Beach goes with drinks from the Freezer and Shooting Range with bullets from the Sports Store.
* For the Further Sunset columns the accompanying Sacramento column depends on the time of the day, but is also unique: before lasers Chestnut Hotel forces the Terrace Garden, while Strip Club forces the Delta Experimental. After the lasers Chestnut Hotel forces the Delta Experimental, while Strip Club forces the Terrace Garden.
* **Reversing** means that the passage open in the new instance is the one to the left of that from the original (with wraparound), but only out of the passages eligible (in parentheses in the above table for each column). Middle doesn't mix with the Lateral, the First doesn't mix with the Further, but Laserites mix with both First and Further. So, for instance, Lasers can only reverse during hours different than the Lasers Hour and if the (preceding) pattern allows for it, and will into the Strip Club during Lateral hours and Freezer during Middle hours. Strip reverses into Hotel; Hotel reverses into Lasers. Terrace reverses into Delta, Delta reverses into Terrace.
* The exception is reversing of the Sacramento types into the Valley column during the Lasers Hour itself, if the Laserites are open
* A passage reversed once during a given hour won't change anymore during that hour. After subsequent vacating its passage will only require another unlocking by killing the 100 infected.
* Valley+Lasers doesn't occur very often in the regular progression of passages, but is a quite frequent a consequence of reboots. In that case, however, the passages apparently behave as already reversed so they supply no information.
* **~!** the current theory is that: If a Sunset-type zone is vacated during the **Crossed pattern** (that is, during a First column hour when the previous hour had the crossed pattern) - it will **reverse to the Laserite**, as long as didn't have to several times (in different hours) since the last lasers hour (for each zone individually). It is known that at least 2 reversals are possible, after their number is exhausted, in subsequent Freezer hours the passage won't reverse anymore even if the zone is vacated several times during the hour. Further research is due.
* **~!!** Similarly, in the **Straight pattern** the **Strip Club** probably has a **limited number of reversals**, but from the **pattern switch from crossed to straight** - this will be examined further.
* By itself, an opening of the Laserites doesn't force a pattern switch; the pattern only switches from straight to crossed during the scheduled Lasers Hour (regardless of whether the Laserites actually open or not) - and 10 to 11 hours later it starts switching back to straight.
* **At the end of the hour all passages advance** - the Sunset type passages go one column to the right, including the First but excluding the Lasers column, and the Sacramento type passages adjust to the Sunset passage depending on the time of day (pattern). If at the end of the hour a passage is reversed, it will **bounce** (will progress to a passage that is both different from the reversed passage just closing and eligible in the new hour).
* Instances of the same zone that have different passages open will synchronize during the nearest First+Middle hour, and subsequently operate the same passages.

## Navigation

If players occupying different instances of a zone form a group, they can use the group's azimuth indicator (around the profile photos) as if they were on the same instance. The exception is if they occupy different floors (which gives false readings even if they are on the same instance). There is no giveaway of being on different instances so when directing players to the frequented cities like Sacramento or Bodega Bay or Santa Rosa always see if the instances' population counts (third button from the left in the top-left row) are the same. A person on a crowded main instance can often enter the substitute through relogging, and a person relogging on a substitute will enter the main instance if there is space. If rescuing someone on a different instance, have both players relog at the same time and they may turn up on the same one.

## Prevalence

Vacating is very frequent for zones like the Highway or Blue Mesa, or Jurassic especially in the small UTC hours, and the subsequent bounce may confuse people as to which passages are open elsewhere.

## Misconceptions

People often expect the same passage to be unable to be open on successive hours. Let's look at an example: at hour X there is Oasis open, for hour X+1 it advances to the Auction Center. If at hour X+1 the Delta Experimental is also open (=the straight pattern), vacating the Jurassic will make its passage reverse to Oasis, and this passage won't change even if the zone was vacated again and again. So, if vacated, later in the hour, at X+1, Jurassic will have exactly the same passage as the hour before. During the other (crossed) pattern the same is possible in the Sacramento- type zones.