Avatar rules

Avatars are bound to certain rules as per the simulation they connect with. A simulation generally has full control over which of the two avatars that are sent with the web protocol or even create new ones for connected Citizens (or autonomous Puppets), but there are established terms for the most common rulesets:

PREF: Default avatars

A default-avatared sim simply uses the default supplied avatars.

OFFL: Human avatars

A human-avatared sim uses the avatars sent as a person's offline-appearance.

There are usually checks in place to confirm that the avatar is indeed human, usually based on a proportion analysis first of the avatar's rig, then the actual surface. If the offline appearance does not match the check, a user is usually expelled. Alternatively, the default avatar is checked (usually more rigorously) - if the default avatar then is human, the default avatar is taken. If neither avatar sent to the server is human, the user is, again, usually expelled at this point - if not, as is the case in Wildcard, the server simply constructs a human avatar.

Most of the time people will mean Citizen mode if they talk about 'a human-avatared sim'. True OFFL-mode requires human avatars even of autonomous Puppets.

HMID: Humanoid avatars

The logic of humanoid avatars roughly checks for a humanoid appearance in default avatars. If given, the avatar is permitted - otherwise, an offline appearance is forced as with a human-avatared sim.

CTZN: Citizen mode

Citizen mode in most settings is indistinguishable from OFFL-mode. It differs in how it treats autonomous Puppets that connect: They get to keep non-human avatars.

Understandably, it's less resource-intense than OFFL-mode, which is why outside of the extremely avatar-conscious Wildcard network it tends to be used far more often than true OFFL-mode. The distinction is usually not made colloquially, though.

CSTM: Custom avatars

All bets are off here - both avatars sent with the web protocol are ignored in verbatim. The simulation creates new ones, sometimes based on the existing avatars sent, sometimes from scratch depending on what the sim requires.