Player Faction in Empyrion: Galactic Survival is to determine which structures belongs to Players. The Core of the player structure has a green light when turned on (if not colored).Pre-Alpha 4.0.0 introduced dedicated multiplayer in Empyrion: Galactic Survival. Player owned faction introduced on Pre-Alpha 4.1.0 update to give ownership of the structure to players , stop griefers and allow players to create closed group (or factions) to share resources and structure between themselves. There are three types of player faction which are described below.The factions for a structure can be selected via drop-down menu on Control Panel GUI of the structures(which can be accessed by 'p') which allowed player to determine if something can be accessed by everyone (PUBLIC) or only by him/herself(PRIVATE) or by the member of the faction in which the player is in (FACTION).
A structure or vessel is considered as Private Faction when only one player can access the structure. The structure/vessel have Private faction by default (Implemented in Pre-Alpha 5.1.0) and belongs to the builder of that structure/vessel. A player can freely change the ownership to private from public (and vice-versa if the private structure belong to him/her) but if changed to Faction, it cannot be changed back to private, unless you are the owner of the Faction. A structure/vessel also becomes Private if all the member of a faction leave the faction. They become private to the last member who leaves the faction.
A structure or vessel is considered as Public Faction when any player can access the structure/vessel. Before Pre-Alpha 5.1.0 all new structures were assigned Public Faction by default. Note that as of Alpha 12.2 the ability to set entity to public as a player was removed, as it was considered an exploit. Note that for the purposes of building a scenario, you can still set this in playfield yamls.
See the Pre-made Public Structures which are in Empyrion: Galactic Survival here
Player Owned Faction
A player can create their own faction or join other factions (if approved by the leader) in multiplayer games. Faction Menu can be accessed by the FACTION button in the Inventory GUI. Upon clicking a faction a menu opens up which list all available factions on that server in the left half of the GUI and the name of the members in the right half. A player can join an existing faction or create their own. If a player applies for a faction, the creator of that faction has to approve the request; no player can auto-join a faction. The Creator of a faction can approve requests, promote members, demote members or kick out via the same menu.
A player can change the ownership of a structure/vessel to Faction so that all the members of the faction can access it.