Wikis / Unreal Wiki / Legacy:Terminology

Got a term that isn't described here? Add it to the list (at its appropriate place) and leave the explanation out. Somebody else will fill it in.

Contributors: Please read the Terminology Style Guide. Also please don't add random UnrealScript variable names to this page, it's not intended for that. (Use the Search instead, please.)

A

Abstract class 

a class which can't be added to a map or spawned in game and is thus only useful as a base class. See Class Syntax.

Accessed None 

UnrealScript warning message, meaning that code attempted to retrieve or alter data via an invalid object reference (also see Log Warnings)

Active brush 

another name for the red builder brush

Actor 

object in three-dimensional virtual space

Algorithm 

implementation, procedure, protocol, or sequence of rules or instructions, (usually for accomplishing a maths-oriented task) that specify the order and kind of arithmetic operations that are used on specified set of data, though technically, a cooking recipe is an example

Alpha Channel 

Information contained within an image file that can be used to determine the intensity of different material properties such as opacity and specularity intensity among other things.

Alpha Map 

An Unreal Tournament Map that is being tested by the mapper, and/or a few other, selected people.

Alpha version 

unfinished software version, not yet feature-complete; not ready for public release.

Animation 

Series of pre-generated, articulated graphic components that convey character motion or behavior, during a scene display, and are called by the animation subsystem in specific game situations

Anti-Aliasing 

System of smoothing out jagged edges on the screen. Video card renders at a higher resolution and then tones it down to your current set resolution.

Anisotropic Filtering 

System to improve quality of textures rendered at various angles.

Assertions 

Code expression that usually evaluates to true or false. Utilized to ensure that components behave properly; typically, checks on execution conditions and performance

Array 

Variable containing an ordered set of values of the same type, indexed by an integer

AI 

Artificial Intelligence; in game development, AI is a code subsystem that controls the behavior of agents (or Bot (UT)s, see Bot Support), objects, and numerous actors; the AI is responsible for realistic, or, intelligent, behavior of opponents during gameplay

Attribute 

synonymous to Property

B

Base class 

higher level, generalized class; used to define characteristics common to all its subclasses. ScriptedPawn is the base class for Unreal I monsters, for example.

Beta version 

unfinished software version, yet considered feature-complete, that's still in testing stage; not yet ready for public release

Bilinear Filtering 

see Bilinear Filtering.

BMP 

bitmap file format (with no or lossless compression)

Boolean 

value that is either true or false

Bone 

An object which describes the relationship of itself to other "bones." Bones usually have vertices attached which move with the bone, thus creating an animation without worrying about the placement of each vertex. See Skeletal Mesh

Bot 

A computer-controlled player character

Botplay 

The gameplay as specifically related to Bot Support

Brush 

piece of geometry that builds the virtual space

BSP 

Binary Space Partition; static data structure method used by game programmers to determine correct front-to-back polygon visibility, so that scenes are rendered realistically

BSP hole 

building bug, yields unwanted invisible obstacles and players falling into geometry and dying

C

Canvas 

the class in the Unreal engine that is responsible for drawing items directly onto a player's display. The most common use of the canvas is in the creation and modification of a HUD.

Casting 

see Typecasting

Class 

type of an object, an object's class defines how an object is implemented; derived from or instantiated by an object, from which it inherits clearly defined attributes. A class can contain: static data members, objects of another class, pointers and references to types and objects of the same or another class, declarations of another class, member functions, and friend classes. All Classes are listed in the Actor browser.

Client 

any linked user (another remote computer terminal, or program, or even another class) of another server, or program, or class is said to be a client of that entity.

Compiler 

software that parses a high-level language, and converts source code to a binary executable program, that will run on Windows, Unix, or some operating system.

Constructor 

method that is automatically called when an object is created; responsible for initializing this object; see Creating Actors And Objects.

CSG 

Constructive Solid Geometry, the general idea behind building geometry in UnrealED.

D

Declaration 

code statement that doesn't produce executable code when compiled, but informs the compiler about new variables and functions (and their types, parameters, and so on)

Destructor 

method that is automatically called when an object is destroyed; responsible for releasing resources (memory, sockets, other objects) used by this object; see destroying objects

DLL 

Dynamic Link Library, file containing native executable code that is bound to another application (or UnrealScript) at runtime

DXT 

some sort of texture compression mojo. See texture format.

Dynamics 

Effects in the map that the map designer put in to make the map more pleasing to the eyes and ears. Examples are Movers, Emitters, and Sounds.

E

Emitter 

an Actor responsible for creating a particle effect; there are two emitter classes in UT2003: Emitter and xEmitter

Engine 

the underlying code framework which makes a complex computer program run.

Enumeration 

ordered set of numeric constants whose values are automatically assigned during compilation (declared with the enum keyword)

Environment mapping 

dynamic UV mapping of a skin on a mesh, depending on the viewer's relative position, producing a mirror-like effect.

Event 

(1) an actor's or trigger's reaction to something, broadcast to actors with matching tags; (2) UnrealScript function called from native code.

F

Face 

see Polygon

FinalBlend 

a texture Modifier

Float 

numerical value capable of storing numbers with digits after the decimal point (like 3.142)

Forward kinematics (FK) 

A term used in skeletal animation, indicating that motion in a skeletal hierarchy (a set of connected bones) is transferred down the hierarchy. Example: rotation applied to a shoulder joint results in rotation of the bones below that joint in the skeletal chain : upper arm, forearm, hands, fingers or claws, etc. See also Inverse kinematics (IK).

FOV 

Field Of Vision (or: Field Of View)

Function 

piece of code with a defined entry point and one or more exit points

Function call 

request for an object to carry out one of its operations. Code command within a program that jumps to a different portion of the code and returns to the statement following the call after executing that code (and may return a data value to it). The function return can be a value, a reference, or a pointer.

Function overriding 

see Overriding

Function prototype 

see Prototype

G

G16 

16 bit grayscale texture. See texture format

Gameplay 

the playability of a game or an element of a game or map; it's relative value in terms of play

Gametype 

a way to implement a mod; specifies basic rules for playing the game (e.g. CTF: get enemy flag and touch your own with it); can be further modified through mutators

Garbage collection 

automatic destruction of unreferenced objects (as in Java, Perl or UnrealScript)

Gimbal lock 

occurs when rotations in successive axes make further rotations either impossible or produce undesired results.

Gibs 

Body parts that fly everywhere when you blow somebody up.

Gold Version 

Version released to the public after the Alpha and Beta versions.

H

Hidden variable 

a variable defined in a class but not accessible in UnrealEd's Actor Properties Window. This is done with the variable syntax var instead of var().

Hierarchy 

an ordering of things (such as objects, classes, people) in a tree-like structure, where things descend or depend on their superiors. Examples: a family tree, the military chain of command. Superseding values affect preceding values, but not vice versa.

HOM 

Hall Of Mirrors effect, a rendering bug

HUD 

Heads-Up Display, rendered on top of the in-game 3D viewport and displaying in-game data like frags, weapons, ammo and scores

I

Implementation 

program code structure that accomplishes some task or sequence of functions (see also Interface)

Inheritance 

relationship among classes wherein one class shares the structure and/or behavior defined in one or more other superclasses

Instantiation 

creation of an object from a class, each object having a copy of its own (non-static) data members

Instigator 

a Pawn which is considered responsible for the damage done by one actor to another; an Actor class property; often used for the InstigatedBy or EventInstigator parameters of Trigger() and TakeDamage() functions

Integer 

numerical value, a whole number without decimals (like 10)

Interface 

user's or client's perception of an object; object-oriented data abstraction is to provide a clean and efficient interface that allows the user to access the underlying implementation

Inverse kinematics (IK) 

A term used in skeletal animation, indicating that motion in a skeletal hierarchy (a set of connected bones) is transferred up the hierarchy. Example: Positioning a hand bone at the end of a skeletal chain results in joints further up the chain (e.g., forearm and upper arm) being relocated as needed. See also Forward kinematics (FK).

Iterator 

special function that allows iteration over all or a given subset of all objects, using a foreach loop

J

JumpSpot 

a NavigationPoint actor indicating a good place for bots to jump to, not from. Also indicates a good point for translocation, double-jump, impact-jump, etc.

K

KillZ 

a Level Properties setting of the lowest altitude that a Pawn can exist. Lower than this altitude, the Pawn is killed. See also StallZ.

L

Lighting 

A combination of the lights in the levels, and the light-maps that are overlayed onto walls, giving the impression of lights on those walls.

Linked List 

List consisting of objects where each item has a reference (link) to the next one.

LOD 

Level Of Detail. Allows high-end machines to display fancy detail (eg weather effects) and low-end machines to just show the essentials. Also allows details to be skipped at farther distances, improving performance. (which allows more details to be shown at closer distances) See, for example, Chain Of Events When Spawning Actors.

Log 

text file which the game writes as it executes.

M

Map Flow 

Map layout design that promotes smooth, fast and exciting gameplay

Masked 

color blending type; makes part of a Texture (UT) transparent (see color blending)

Material 

rectangular image (bitmap) that can be applied to brush surfaces and meshes or directly drawn on a canvas; also see texture

Mesh 

three-dimensional representation of an Actor in virtual space (like weapons, pickups, players)

Method 

function (piece of code) that deals with objects of a given class; defined by the object's class

Mod 

short for modification; modification of a game can add new rules or content and in UnrealEngine games (like Unreal or Unreal Tournament) a modification can be implemented as a Mutator, a gametype, a total conversion, a player model, a VoicePack, an AnnouncerPack and a few other ways

Modulated 

color blending type; mid-gray is transparent, black and white are opaque (see color blending)

Mover 

movable Brush (for doors, elevators and visual effects)

Mutator 

a way to implement a mod in UnrealEngine games; mutators usually just change a certain aspect of the game, but there are also mutators with large scale modifications (e.g. weapon mods, competitive mods); mutators are stackable with other mutators to combine their modifications

MyLevel 

a special name for a package. Using this tells UnrealEd to embed a resource in the current map file.

N

Name 

unique specifier for an object or class (or something else) in UnrealScript; unlike strings, can't be modified like a string value and may not contain anything except letters, numbers and underscores

Native code 

code that can be interpreted by a computer's processor without any intermediate steps. In Unreal, this is C++ code in DLL files.

Newbie 

a person that's new to and hence unexperienced in something.

N00b 

same as Newbie, but is contemptuous (is that a good word for them?) about being that. They are sometimes poseurs.

Node 

the polys that are seen in Zone/Portal view. They correspond to surface polygons split by BSP cuts. See polygon and node count.

Node count 

a measure of how much rendering work the engine has to perform to display a view of a map. Also the total number of nodes in the name.

Null 

Texture(s) that is missing or can not be found. These null textures are given a default texture used by the engine (The green bubbly texture).

O

Obfuscation 

Creating code that works but is difficult to understand or work out what it actually does.

Object 

abstraction that typically is assigned clearly specified characteristics; in other words, a chunk of data with a certain class associated to it; the class describes the data structure and contains the code that deals with objects of that class

OCD 

Object Collision Detection

OOP 

Object Oriented Programming

Overloading (a function) 

redeclaring and reimplementing a function with the same name as an existing function, but a distinguishable set of parameters (like having two versions of a function, one of them working for float parameters, one of them for integer parameters)

Overriding (a method) 

redeclaring and reimplementing a method in a subclass

Overwriting (a method) 

see Overriding (a method)

Owner 

Constant Actor declared in the Actor class, specifies who or what owns this object. Use native SetOwner( actor NewOwner ); to set the owner.

P

Package 

a file containing resources for Unreal engine games (like code, decorations, sound, music, maps, or all of it)

Pathing or Bot Pathing 

supporting bot navigation of a level (see Bot Support)

Palette 

look-up table of colors used in a bitmap

Pawn 

The parent class of all creatures and players in Unreal which are capable of high-level AI and player controls.

PCX 

bitmap file format (with no or lossless compression)

Pivot 

point about which a brush is rotated or scaled.

Pointer 

variable that "points to" an object's memory location; in UnrealScript, all object variables are (typed) pointers, but there's also an unspecific pointer variable type that serves as a placeholder for C++ pointers in native code

Polycount 

either number of polys currently drawn on screen by the engine, or the total number of polygons in the map.

Polygon 

two-dimensional, flat, closed shape in three-dimensional space, like a brush surface. Currently Unreal Tournament only supports convex polygons.

Prefab 

A collection of Actors, such as CSG brushes and/or lights that can be copied and used over and over again in a map. ( Useful for distributing map parts without sacrificing storage space since a .t3d (Unreal Text) file is much smaller than a .ut2 file )

Private (method or property) 

not accessible from outside the class this method or property has been declared in (see Public (method or property))

Probe function 

A function that can be enabled or disabled using the Enable and Disable methods. These functions are usually defined as "events" and are called by native engine code.

Property 

individual item of an object's data; defined by the object's class

Prototype 

number, order and types of function parameters

Projector 

UT2003's replacement for the deprecated Decal class. Allows for projected shadows (ShadowProjector class) and other neat stuff.

Public (method or property) 

accessible from outside the class this method or property has been declared in (see Private (method or property))

Q

Quad 

a single grid element of terrain.

Quaternion 

mathematical entity similar to a complex number. These can be used to represent 3D rotations in a way that eliminates the gimbal lock problem with non-l33t rotational matrices; popular with game programmers for this very reason

R

Ray tracing 

Calculating the lighting in a level by tracing exactly where the light goes.

RBB 

red builder brush

Rendering 

subsystem that actually produces the visible scene that is displayed on the computer terminal for players to yell at; consumes the majority of CPU computing capacity

Replication 

generic term for sending game-relevant data back and forth between a network server and its clients

RGB8 

texture format with three channels (red, green, blue) and 8 bits per channel

RGBA8 

texture format with four channels (red, green, blue, alpha) and 8 bits per channel

S

Shader 

SHAS 

"Sudden Heart Attack Syndrome". Dying for no apparent reason. Sudden cratering is usually caused by BSP holes (see 'BSP hole').

Sheet 

a brush which does not enclose a 3D volume, usually because it's a single polygon.

Simulation 

generic term for simulation or prediction (not authoritative) of game behaviour on network clients

Skeletal animation 

mesh animation by having vertices attached to interlinked bones; see Animation

Skin 

set of textures that are applied to a mesh (for instance, a Bot (UT), a player or a decoration)

Sky box 

see page

Solidity 

see page

Source (code) 

original high-level computer language code, like C++ or Java, that is compiled into an executable program

Spawn 

UnrealScript command for creating a new Actor

Spawndeath 

an error condition during map Playtesting where the player character repeatedly dies, as if automatically suiciding.

StallZ 

a Level Properties setting of the highest altitude a flying Vehicle can fly before it's thrust power is deactivated. See also KillZ.

State 

a concept in UnrealScript that allows actors to execute different code in different circumstances. For example, a Bot can be 'Fleeing', 'Attacking', etc. See State and also InitialState

State code 

code that is outside of functions in a state block

Static Mesh 

see page.

Structure 

ordered arrangement of typed data items; similar to a class in UnrealScript, but can't be referenced (only copied) and doesn't have methods

String 

value of text; for instance, a message somebody typed in

Subclass 

class derived from another class (its base class, or superclass); inherits properties and methods from the superclass unless they're expressly overwritten

Surface 

see page.

Syntax 

the rule of arranging and ordering commands to form a code. UnrealScript grammar, if you will; see class syntax and function syntax

T

Texel 

Texture pixel (as opposed to screen pixel)

Text Parsing 

the act of using a routine or function of some sort to change symbols in a string variable to reflect the values of certain variables, e.g. replacing "%k" in a death message with the killer's name; see Message Placeholder

Texture 

rectangular image (bitmap) that can be applied to brush surfaces and meshes or directly drawn on a canvas; special type of material

Total conversion 

mod attempting to totally change the underlying game into a different game by providing all-new content (game types, user interface, weapons, maps, models, menus)

Trace 

follows a straight line through the world, usually until it hits solid geometry. Usually used to determine where bullets hit.

Translucent 

color blending type; black is transparent, white is opaque (see color blending)

Trigger 

An actor in a level which, when touched, will activate some effect, or other event.

Typecasting 

converting one type of variable to another (e.g. Float to Integer)

U

UC file 

An UnrealScript source code file (Unreal Class), readable in any plain-text editor.

UAX 

UT's and UT2003's sounds format.

Ucc 

UnrealScript execution environment, ucc.exe in the System subdirectory

UMOD 

Unreal Mod installer

UMX 

UT's music format.

Unlit 

(Texture (UT)) rendered without any lighting applied to it; yields a bright, uniform appearance

USA file 

In Unreal 1, Unreal 2, and OldSkool for UT, a file created to save data from a singleplayer game in progress.

UT2MOD 

UT2003's UMOD format

UU 

Unreal units, used to measure and specify lengths within the engine's virtual space

UV mapping 

two-dimensional application and alignment of a skin on a mesh

V

Variable 

memory location with a symbolic name where a program can store information for future retrieval

Vertex 

point in (normally two- or three-dimensional) space; point where polygon edges meet

Vertex animation 

mesh animation by playing a set of different, fixed vertex arrangements (like stop-motion animation in movies); see Animation

Viewport 

Window in UnrealEd which shows one view of the map that is loaded; a class in UnrealScript that represents the local player

W

Wiki 

collaborative, open project on the web, gathering knowledge on a certain topic

WarpZone 

special kind of zone. A WarpZone's portal renders what can be seen from the destination portal, and also teleports players and objects which enter it to the destination portal.

Z

Z-axis 

The third axis in a 3D co-ordinate system. In FPS games, this also refers to things (architectural detail, enemies, etc) being above or below the player.

Zone 

Portion of a map's space that is sectioned off, either to achieve special effects (gravity, water, etc.) or for engine optimization

Zone portal 

Type of polygon (usually built with a sheet brush) which tells the engine where zone boundaries lie.

Related Topics

Some other pages that may help:

• File Format – Summary of all the file formats encountered when working with Unreal
• Texture Format
• udn2:UnGlossary
• External Link: IceCreamYou's Key Terms – A very comprehensive list of terminology

Discussion

Sweavo: I would have thought UScript's semantics would be better thought of as references rather than pointers, since it's not meaningful to increment a reference, whereas incrementing a pointer has some meaning, albeit ill-defined...? Also since non-native functions are executed in bytecode (aren't they?) then actual pointers (in the hardware sense) are not passed around in executing unrealscript are they? I imagined array indices.

IceCreamYou: I took the liberty of adding a link to my own Key Terms page... I can't guarantee there aren't a few errors, but it is a very complete list.