NURBS: Stands for non-uniform rational B-splines. A 3D graphics technique for cre-
ating curved surfaces, a detailed explanation of which should be sought out in a 3D
graphics programming book.
On a RailorOn Rails: A game is said to be on a rail when players are forced to move
through the game in a very specific, carefully controlled way, as if they were locked onto
a rail that ran through the game. Games that are said to be “on a rail” or “on rails” are
very linear games. A specific type of game called a “rail shooter” is on rails to such an
extent that the flight path of the player’s vehicle is completely predetermined, and play-
ers are only able to shoot at targets as they pass by.Rebel Assaultis an example of a rail
shooter.See alsoLinear.
180 Degree Rule: A film technique for cutting a scene that says that the camera
must always stay on one side of a line that extends between the two centers of attention
in the frame. If the camera never rotates anywhere outside of those 180 degrees, the
audience will not become confused by the scene’s cuts from character to character.
Online: A game that is played online is run over any sort of a network, whether a
LAN or the Internet. Typically online games are multi-player, and, since each player has
his own machine and display, allows each player to have a blind-play experience, where
other users cannot see what tactics he is using. This makes online games play signifi-
cantly different than single system multi-player games.
Parser: In gaming, often refers to the input method used by text adventures. A
parser takes natural language words or sentences the player enters and translates them
into commands that the game logic can understand. Parsers can become quite sophisti-
cated while still failing to understand many of the sentences that players attempt to use
as commands. Natural language processing is a major field of AI research, one that is
still far from perfect, so it is no wonder that parsers have as much trouble as they do. A
more modern usage of the term parser is in reference to the interpreter for a game’s
scripting language.See alsoText Adventure.
Pathfinding: This is the portion of the AI code that allows an agent to figure out how
to get from one location to another in the game-world. Ideally, pathfinding allows the AI
agent to avoid getting stuck on obstacles or other agents, yet pathfinding in many
games is less than perfect. There are various algorithms, such as A, that can be used
for pathfinding, which may have different results in terms of efficiency and the quality of
the paths generated, though that is a topic better explored in a book about program-
ming.See alsoA.
PC: May refer either to a game’s player character or to the Intel-based personal com-
puter originally popularized by IBM and powered by MS-DOS.See also Player
Character.
Persistent: A persistent game is one that continues running and maintaining the
state of the game-world regardless of whether a particular player is actively playing it
or not. Often persistent games are also massively multi-player, and vice versa. MUDs
were one of the first persistent games, while commercial products such asUltima
OnlineandEverQuesthave made persistent games quite popular to mainstream
gamers.See alsoMUD.
Pitch Document: SeeConcept Document.
666 Glossary