View source for Persistent Game Worlds

[[Category:Patterns]]
[[Category:Diegetic Patterns]]
[[Category:Needs revision]]
[[Category:Needs references]]
''Game worlds that exist independently of players' game and play sessions.''

Through having people or servers dedicated to them, some games can have game worlds that are always available for players to enter them. This means that these [[Persistent Game Worlds]] exist independently from players' game and play sessions. This does not necessarily mean that everything that happens in them affect its future, parts of the entirety of them can be reset but this does not change that they are available continuously (with the exception for temporary server restarts).  

=== Examples ===
Each [[:Category:Tabletop Roleplaying Games|Tabletop Roleplaying Game]] (e.g. [[Call of Cthulhu]] and [[Hârnmaster]]) spawn many different [[Persistent Game Worlds]] as game masters start campaigns. These game world can easily survive changes in player composition and even changes in whom does that game mastering.

MUDs (e.g. [[Kingdoms]] and [[DragonMud]]) and [[:Category:Massively Multiplayer Online Games|Massively Multiplayer Online Games]] (e.g. [[Ultima Online]], [[World of Warcraft]], and [[Entropia Universe]]) have complex and dynamic [[Persistent Game Worlds]] where players' game sessions with a single character can last for years. [[Minecraft]] servers supporting several players can be created with similar properties. Similarly, Massively Single-Player Online Games such as [[FarmVille]] continue updating for all players regardless of which players are playing. The life time of game instances for these kinds of games are mainly determined by how popular or commercially successful the games are, and these [[Persistent Game Worlds]] can even survive software generations. 

[[:Category:Alternate Reality Games|Alternate Reality Games]] such as [[Prosopopeia]] and [[Conspiracy for Good]] hide in the real world and thus makes it part of them. This of course means that these parts continue to exist independent of game and play sessions.

== Using the pattern ==
[[Persistent Game Worlds]] are basically [[Game Worlds]] that have [[Dedicated Game Facilitators]] maintaining them so they are available when players wish to enter them. This is most easily done by computer programs but human [[Game Masters]] can also provide this service, although the accessibility may be more restricted and this adds [[Excise]] for them. The latter is the norm in tabletop [[Roleplaying]] games such as [[Call of Cthulhu]] and [[Hârnmaster]] although players often help with some of the task involved. [[Persistent Game Worlds]] make most sense for [[Multiplayer Games]], especially [[Massively Multiplayer Online Games|Massively Multiplayer ones]], but are also needed for [[Massively Single-Player Online Games]] that are [[Tick-Based Games|Tick-Based]] or support [[Visits]].

One typical requirement of [[Persistent Game Worlds]] is to keep track of [[Characters]] and [[Game Items]], but not all [[Game Items]] need to be persistent (e.g. [[Power-Ups]]). For [[Tick-Based Games]] this means updating them whether or not players interact with the game system between ticks. This may include activating [[Resource Generators]] and [[Spawn Points]] but this may also require other functions to avoid creating too many instances or to [[Encouraged Return Visits|Encourage Return Visits]] more frequently. The latter can for example be to have [[Budgeted Action Points]] that are [[Regenerating Resources]] which replenish over time. The handling of [[Resources|Resource]] flow needs to be handled for other purposes as well, including balancing the value of the various kinds of [[Resources]] against each other and ensuring that there are not too little of any type. This means considering overall how [[Producers]] and [[Consumers]] can interact in [[Producer-Consumer]] chains to create [[Emergent Gameplay]], and how specific issues such as [[Spawning]] and [[Crafting]] should be handled. One solution is to try and create [[Closed Economies]] (which was tried for [[Ultima Online]] but didn't find a stable equilibrium) or a [[Faucet/Drain]] model (e.g. [[World of Warcraft]] or [[FarmVille]]). In general, [[Persistent Game Worlds]] need to have all [[Resources]] as [[Renewable Resources|Renewable]] ones rather than [[Non-Renewable Resources|Non-Renewable]] ones.

Existing independently of players' play sessions is rather pointless if players need to synchronize when they should all interact with the [[Persistent Game Worlds]]. For this reason, use of the pattern implies  supporting [[Late Arriving Players]] and [[Drop-In/Drop-Out]] gameplay and making an [[Asynchronous Games|Asynchronous Game]]. [[Private Game Spaces]] strengthens this since it limits the amount of interaction possible between the players. While the [[Freedom of Choice]] to play may lessen the feeling of having to play these games, [[Construction]] and other forms of [[Creative Control]] (up to making the worlds [[Player Constructed Worlds]]) can increase the wish to play them since the creations continue to exist after the players' play sessions end. Although games with [[Persistent Game Worlds]] may easily have enough skill requirements to support [[Game Mastery]] and can let players play long enough to develop it, this ability to train may make it difficult to provide [[Higher-Level Closures as Gameplay Progresses]] for these players without resolving to [[Red Queen Dilemmas]]. This can to some extent be countered by [[Grinding]] but risks making players lose a sense of [[Value of Effort]]. MUDs such as [[DragonMud]] and [[Kingdoms]] introduces [[Construction]] and other forms of [[Creative Control]] to these expert players to provide [[Varied Gameplay]] and thereby other types of possible closures. Other types of [[Varied Gameplay]] can be introduced by [[Dedicated Game Facilitators]] through [[Expansions]] or [[Evolving Rule Sets]] for similar reasons.

Nearly all [[Multiplayer Games]] have some possibility for [[Social Interaction]] but [[Persistent Game Worlds]] let these interaction develop over time. This allows for formalized structures such as [[Guilds]] to appear if supported, as well as informal ones such as [[Game-Induced Player Social Status]] and [[Internal Rivalry]]. These various forms of [[Social Interaction]] may often be the main source why games with [[Persistent Game Worlds]] have [[Encouraged Return Visits]] - this can be increased by design options such as [[Altruistic Actions]], [[Delayed Effects]], [[Development Time]], [[Events Timed to the Real World]], and [[Delayed Reciprocity]]. [[Encouraged Return Visits]] can also be constructed from [[Ephemeral Events]] but only if players are aware of them, e.g. through [[Extra-Game Broadcasting]] or by being seasonal.

Given the many aspects of [[Resources]], and possibly [[Construction]] or [[Character Development]] present in [[Persistent Game Worlds]], there are often opportunities to include [[Trading]] in the design, both in-game and as [[Extra-Game Actions]] with [[Extra-Game Consequences]].
For games with [[Game Items]] is may be more or less impossible to avoid [[Game Element Trading]], and through this [[Purchasable Game Advantages]] although in the latter case the game facilitators can be the sellers of the [[Game Items]].

=== Diegetic Aspects ===
As mentioned below in the section of narrative aspects, [[Persistent Game Worlds]] can have problems with [[Thematic Consistency]] unless using [[Never Ending Stories]].

=== Narrative Aspects ===
Games with [[Persistent Game Worlds]] cannot have fully [[Predetermined Story Structures]] but must instead rely on [[Never Ending Stories]], or accept to break the [[Thematic Consistency]] by [[Spawning]] [[Quests]] and [[Instances]] that contain small [[Predetermined Story Structures]]. Providing the content of [[Never Ending Stories]] may be left to the [[Randomness]] of [[Resource Generators]] used (arguably used in [[Minecraft]]), [[Game Masters]], or the players through giving them [[Creative Control]] for this through [[Storytelling]]. This kind of [[Storytelling]] is usually based on the players doing [[Roleplaying]] with their [[Characters]] and as the [[Storytelling]] does not have an immediate effect on the state of the [[Game Worlds]],  worlds supporting this type of gameplay typically generate significant amounts of [[Extra-Game Actions]] and [[Extra-Game Consequences]].

Related to the developing of a narrative is if the events caused by gameplay have persist or simply get removed due to [[Spawning]]. While some games like [[Minecraft]] support the former through [[Persistent Game World Changes]] this is difficult to combine with re-occuring [[Quests]] in [[Massively Multiplayer Online Games]] like [[World of Warcraft]]. [[Player Constructed Worlds]] are also typically easy combined with [[Persistent Game World Changes]] as are games with human [[Game Masters]]. Although supporting these permanent changes pose problems with generating content these changes are at the same time often necessary for [[Creative Control]] to have a [[Value of Effort]].

== Consequences ==
[[Persistent Game Worlds]] can encourage players to view [[Character Development]], and especially [[Player-Planned Development]], as [[Investments]] having a [[Value of Effort]] that they feel [[Ownership]] of, this since these can be developed over a long period of time and there is no predetermined point in time when they will stop being valuable. By doing so, the persistence of a [[Game Worlds|Game World]] may change how [[Roleplaying]] is conducted (e.g. not taking the risky chances often since the law of averages will make this a bad strategy). Examples of these kinds of attachments are common in games such as [[Ultima Online]] or [[World of Warcraft]] that have strong foci on [[Characters]], but do often spill over to [[Factions]] or what is created through [[Construction]] (examples of that latter can be found in [[FarmVille]] and multiplayer servers for [[Minecraft]]). In general, these effects are strengthen the more [[Creative Control]] players are given up to the level where the worlds are [[Player Constructed Worlds]]. 

The support for [[Late Arriving Players]] and [[Drop-In/Drop-Out]] gives players a [[Freedom of Choice]] when to play games with [[Persistent Game Worlds]], especially when they contain [[Private Game Spaces]]. However, this may be countered by [[Encouraged Return Visits]].

When the [[Investments]] players have done in [[Persistent Game Worlds]] are recognized by other players as having [[Value of Effort]] this can lead to the [[Extra-Game Actions]] of [[Purchasable Game Advantages]], that is the [[Game Element Trading]] of [[Characters]] and [[Game Items]] using real world currencies.

Since [[Persistent Game Worlds]] need to either maintain the effects on [[Game Items]] or the [[Character Development|Development]] that [[Characters]] have had, it is impossible to have full [[Reversibility]] in [[Persistent Game Worlds]] and they typically strive to have [[Temporal Consistency]]. This also means that small effects tend to escalate over time. Because of this it may be very difficult to avoid [[Emergent Gameplay]] of some sort and possibilities for [[Crafting]], [[Abstract Player Construct Development]], or [[Character Development]] can easily lead to ruining [[Player Balance]].

== Relations ==
=== Can Instantiate ===
[[Asynchronous Games]], [[Emergent Gameplay]], [[Excise]], [[Extra-Game Actions]], [[Extra-Game Consequences]], [[Freedom of Choice]], [[Game-Induced Player Social Status]], [[Internal Rivalry]], 
[[Social Interaction]], 
[[Temporal Consistency]], 
[[Trading]], 

==== with [[Altruistic Actions]], [[Delayed Effects]], [[Delayed Reciprocity]], [[Development Time]], or [[Ephemeral Events]] ====
[[Encouraged Return Visits]]

==== with [[Budgeted Action Points]] and [[Regenerating Resources]] ====
[[Encouraged Return Visits]]

==== with [[Character Development]] or [[Player-Planned Development]] ====
[[Investments]], [[Value of Effort]]

==== with [[Construction]] or [[Creative Control]] ====
[[Varied Gameplay]]

==== with [[Game Items]] ====
[[Game Element Trading]], 
[[Purchasable Game Advantages]]

=== Can Modulate ===
[[Characters]], [[Character Development]], [[Factions]], [[Game Items]], [[Game Worlds]], [[Massively Multiplayer Online Games]], [[Multiplayer Games]], [[Player-Planned Development]], [[Roleplaying]], [[Resource Generators]], [[Spawn Points]], [[Tick-Based Games]]

[[Massively Single-Player Online Games]] that are also [[Tick-Based Games]] or support [[Visits]]

=== Can Be Instantiated By ===
[[Dedicated Game Facilitators]], [[Game Masters]]

=== Can Be Modulated By ===
[[Closed Economies]], [[Construction]], [[Consumers]], [[Crafting]], [[Creative Control]], [[Drop-In/Drop-Out]], [[Encouraged Return Visits]], [[Ephemeral Events]], [[Expansions]], [[Faucet/Drain]], [[Grinding]], [[Guilds]], [[Instances]], [[Never Ending Stories]], [[Late Arriving Players]], [[Persistent Game World Changes]], [[Player Constructed Worlds]], [[Predetermined Story Structures]], [[Private Game Spaces]], [[Producers]], [[Producer-Consumer]], [[Purchasable Game Advantages]], [[Quests]], 
[[Regenerating Resources]], 
[[Renewable Resources]], [[Roleplaying]], [[Spawning]], [[Storytelling]]

=== Possible Closure Effects ===
-

=== Potentially Conflicting With ===
[[Non-Renewable Resources]], [[Predetermined Story Structures]], [[Reversibility]],
[[Thematic Consistency]]

[[Player Balance]] when [[Crafting]], [[Abstract Player Construct Development]], or [[Character Development]] exists in the game

== History ==
An updated version of the pattern ''Persistent Game Worlds'' that was part of the original collection in the book ''Patterns in Game Design''<ref name="Bjork & Holopainen 2004"/>.

== References ==
<references>
<ref name="Bjork & Holopainen 2004">Björk, S. & Holopainen, J. (2004) ''Patterns in Game Design''. Charles River Media. ISBN1-58450-354-8.</ref>
</references>

== Acknowledgements ==
Peter Lönnqvist