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Used to describe raycasting engines, such as Doom or Duke Nukem. The maps are generally drawn as 2D bitmaps with height properties but when rendered gives the appearance of being 3D.


Used to describe raycasting engines, such as Doom or Duke Nukem. The maps are generally drawn as 2D bitmaps with height properties but when rendered gives the appearance of being 3D.


Refers to the ability to move in the X, Y and Z axis and also rotate around the X, Y, and Z axises.



Axis-aligned Bounding Box (AABB)

A form of a bounding box where the box is aligned to the axis therefore only two points in space are needed to define it. AABB’s are much faster to use, and take up less memory, but are very limited in the sense that they can only be aligned to the axis.


An albedo is a physical measure of a material’s reflectivity, generally across the visible spectrum of light. An albedo texture simulates a surface albedo as opposed to explicitly defining a colour for it.

Alpha Blending

Assigning varying levels of translucency to graphical objects, allowing the creation of
things such as glass, fog, and ghosts. This can be accomplished by using alpha channels.

Alpha Channel

The optional channel of image data in a texture file that can be used as a transparency map, height map, specular map, etc. The format of the alpha channel is usually 8 bits per pixel (256 colors), though certain file formats support different bit depths.

Alpha Testing

A method for creating transparency by checking the alpha value of a given pixel.


An animated storyboard which is used to refine timing, cameras, composition, when a complex shot is needed and static images have trouble making intention clear. When needed, low-resolution animated 3d scenes are used, intermixed with the remaining 2D storyboard panels.

Anisotropic Filtering

A texture filtering method, specifically for non-square filtering, usually of textures shown in radical perspective. Generally speaking, anisotropic improves clarity of images with severely unequal aspect ratios.

Anti-aliasing (AA)

Removes the stair-stepping or jaggies which occur at the edges of polygons or between the texels on the polygons. The way this works is by interpolating the pixels at the edges to make the difference between two color areas less dramatic.

Artificial Intelligence (AI)

A set of computer instructions or algorithms designed to simulate the actions of an intelligent being to the extent necessary to meet the design requirements of a game.


An acronym for the American Standard Code for Information Interchange, which is an encoding method for text, based on the English alphabet.

Aspect Ratio

A number that describes the shape of a rectangle texture, whether it’s tall or wide. To calculate an aspect ratio, either divide the width by the height, or write it out as width:height. 



Back Buffer

A secondary surface where the current frame’s graphics are stored before they are transferred to the primary display surface.

Backface Culling

The process of removing the unseen polygons that face away from the camera in the game. These surfaces are usually not needed (except sometimes for shadow casting). Doing so can dramatically speed up the rendering of a polygonal scene.

Bezier Spline

This type of spline provides the ability to make a curved line using very few points. The two endpoints of the curve are called anchor points. The other points, which define the shape of the curve, are called handles, tangent points, or nodes.


A term commonly used in games to describe a camera-facing plane. This is a polygon with a texture using transparency, that rotates on various axes to always face the player. Billboards are commonly used for particles, trees, grass, clouds, and UI elements.

Bit depth

This value defines the amount of color information an image holds. Typically 1-bit is two colors
(black and white), 2-bit is four colors, 4-bit is sixteen, 8-bit is 256 colors, and 16-bit is 65536 colors.


An image file, such as JPG, TIF, PSD, and BMP.

Binary Space Partition (BSP)

A BSP tree subdivides 3D space with 2D planes to help speed up sorting. In game development, BSP usually means using solid modeling techniques to carve the basic surfaces of a game level.


A post-processing effect which simulates bright light sources overwhelming a camera or the eye, creating a halo around the brightest parts of a scene.


A Bitmap file type used in game development, for storing source files. This is an intermediary format for use outside of a game engine. Usually then imported and converted into a different in-game format.

Bounding Box

A simplified approximation of the volume of a model, most commonly used for collision detection. It is common place to find referenced in code axis-aligned bounding box (AABB) and oriented
bounding box (OBB).

Bump Mapping

A process of rendering polygons that gives them an illusion of depth.




typically the camera in a game is the player’s view into the game scene. Cameras can also be used
for other views in the game level, for example a virtual security camer can use “render to texture“ to show the player alternate views of a game level.

Cartesian Coordinate

The standard coordinate system. With three dimensions, there are three scalars, x, y, and z used to represent a point at a given distance from a reference point, the origin.

Cel Shading

A technique which causes rendered objects to look as though they are hand-drawn, cartoon


Commonly used to describe a color component that makes up an image. A 24-bit image can have
red, green, and blue channels. 32-bit images have room for a fourth channel, commonly known as an alpha channel.


Any node in a hierarchy that is attached to another node.

Clipping Plane

This plane throws away polygons on the other side of it. This can dramatically speed up the rendering of a polygonal scene, since unneeded polygons can take up valuable processing power.

Collision Detection

The systematic check to see if any intersections are occurring between significant polygons. A common method to optimize collision detection is to use a bounding box to simplify collision


Programmers have to convert source code, written in a high-level language such as C++, into
object code (aka Assembly), so that a microprocessor can run the application.


Defined where any two points can be connected by a line that goes outside the shape. When
visualized the shape takes the formation of the letter C.


Defined where any two points can be connected by a line that goes outside the shape. This is a
shape without indentations and is the opposite of a concave surface.


Artifacts that appear around a bright light source. Often in circular or star like shapes.


Commonly utilized to compute something known as a surface normal. As by the cross product formula, a normal is simply a vector that is perpendicular to some plane. In graphics, this plane is
usually a polygon of some type.

Cube Mapping

an alternative to sphere mapping used in environment mapping, cube mapping gets a ‘screenshot’ looking in 6 different directions and arranges them in a rolled out cube. When applied, the object appears to reflect the environment around it.



Depth Cueing

Scene effect to make objects that are farther away from the camera are rendered with a
lighter color so that they are given the illusion of distance.


Process of creating an illusion of more colors than are really available in the current color depth
by creatively arranging individual pixel patterns.

Draw Call

These calls are based on how many objects are drawn to the screen. A good way to think about
this is 1 material = 1 draw call, and an object with 4 materials = 4 draw calls. This can grow exponentially when incorporating the lighting and shadows in a scene.

Draw Order

the way to define what polygons are drawn in a game engine. Back-to-front draw order means the furthest polygons are drawn first, and the rest are drawn on on top of another, with the last to draw being the one that appears to be in front. This can also be referred to as “sort priority” regarding transparent polygons as well.

Dynamic Lighting

The definition of dynamic lighting is a light source that is updated every frame, as you’d want for moving lights and for characters that move amongst various light sources. The opposite of dynamic lighting is “baked” lighting through lightmapping.




A game engine is what converts all the game assets into the display on your computer screen. Game engines often come with a level editor and other tools which help artists create content that work well in the engine.

Environment Probe

An effect where an object reflects its surroundings, much like chrome.


An expression is a formula used to create procedural animation, often using mathematical elements like sine and cosine. Expressions can automate and greatly speed up repetitive animation tasks.




Face is another name for a Polygon. This term can be used specifically for a single triangle or more generally for a multi-triangle polygon.

Facial Action Coding System (FACS)

A system to taxonomize human facial movements by their appearance on the face, Movements of individual facial muscles are encoded by FACS from slight different instant changes in facial appearance. It is a common standard to systematically categorize the physical expression of emotions, and it has proven useful to psychologists and to animators alike.

Field of View (FOV)

The FOV is usually defined by its width in degrees. A typical FOV in games is around 60 degrees, although players enjoy being able to change the FOV themselves.

Flat Shading

Assigning only one color shade per face.


Fog makes objects become more and more the same color as they recede into the distance. This is similar to real fog, except that game fog is a perfect gradient, whereas real fog usually has some wispy qualities to it. Heavy fogging in a game is used to disguise the far clipping plane.

Forward Kinematics (FK)

A method of manipulating objects in a hierarchy where the animator positions objects and the program calculates the positions and orientations of the objects below it in the hierarchy.

Frames Per Second (FPS)

A measure of animation display rate. Not to be confused with the genre First Person Shooter.

Frame Buffer

What a video card uses to store the images it renders, while it is rendering them. When it is
done rendering, it sends the completed frame to your monitor and starts building the next frame.

Frame Rate

Measures how fast the game is being rendered. Generally if the frame rate is lower than 30
frames per second, then the game will seem “choppy” and unresponsive.


A term from traditional photography, the shape that the camera creates when projected into the
scene. This pyramidal shape defines the limits of what the viewer can see, so it is used to calculate clipping, collisions, Fog, etc.




Geometry is commonly used to define all polygonal objects in a game. Also called a mesh.


Graphics Interchange Format. A format for saving graphics that usually uses a 8-bit (256 color)
indexed bitmap.

Gimbal Lock

A problem encountered when one tries to rotate using the 3 axises where one ends up rotating in the wrong direction after several rotations.

Gouraud Shading

Also known as intensity interpolation. A shading model where the light intensity is calculated at each of the vertices, and is interpolated across the polygon.


Graphical User Interface.




Real world lighting contains a high range of luminance values. HDR, or High Dynamic Range lighting, is essentially a technique that exceeds the normal computer graphics color range of 0 to 255, allowing for more realistic lighting models.

Height Map

A method often used to create 3D landscapes, height maps contain a grid of points that are
given height values and the landscape is rendered by building polygons out of them.


Existing where each node can trace its lineage up through this upside-down tree, back though
parents to the root. If you choose any parent, then you can call its collection of children a branch of the tree.


Heads-Up-Display. This means status information which are always visible like health or ammo information.



Indexed Color

When color information is stored in a look up table that contains the colors red, green and
blue information.


The process of determining from two or more values what the “in-between” values should be. Interpolation is used with animation and with textures, particularly texture filtering.

Inverse Kinematics (IK)

The process of creating realistic positioning of a complex object, such as an arm, based on the positioning of a lower-level node in the skeletal hierarchy, such as the twisting of a hand. This process works in the reverse of forward kinematics.




A bitmap file type used in game development. This format is often used for web games, because it
can be highly compressed for faster download. After the download it is usually converted into a different in-game format to use in the game.




An abbreviation for Linear Interpolation.

Light Mapping

Traditionally, light maps store the color and brightness of pre-baked lighting. The Diffuse map is applied to the mesh with no lighting, and the light map is then multiplied against it, darkening the diffuse where the light map has shadows.




This can either mean texturing or it can mean creating texture coordinates.


A set of parameters that determine the textures, color, shininess, smoothness, etc. for a surface. A
material is the user interface for a shader; the shader controls how the surface is rendered, while the material merely stores the user-adjusted settings for the shader.

Material IDs

Used to split a model’s surface into multiple Materials. Normally a model can only use a single material. However a number can be assigned to sets of polygons which each correspond to a particular material.


The amount of quickly-retrievable space for storing the assets currently being used by the game.
Games use a number of different types of memory, but game artists are mostly concerned with RAM. The biggest question for the artist is how much RAM is available for textures.


Another word for geometry, or polygon.

Mip Mapping

To render a texture more smoothly in a game, it is resized multiple times to make “mips,” which are smaller versions of the texture. These smaller versions are swapped or blended with the original texture as the texture recedes in the scene.


An animated 2D or 3D effect that makes one texture or geometry smoothly transform into another.
When used with models, all the shapes must have exactly the same vertex count, and vertex order. The individual mesh shapes are called blend shapes, or morph targets.




This means a polygon with “n” number of sides. It can be used interchangeably with polygon. The
letter N stands for any whole number. A 3-sided n-gon is a triangle, a 4 sided n-gon is called a quad.


Each single object in a Hierarchy is called a node. Without nodes there can be no hierarchy-- there’s nothing to link together. Also sometimes called a bead.


Short for Non-Uniform Rational B-Spline, a mathematical representation of a 3-dimensional object. Most applications support NURBS, which can be used to represent analytic shapes, such as cones, as well as free-form shapes, such as car bodies.




Defined as a screen pixel being drawn more than once. Overdraw is usually caused by multiple
triangles being drawn over each other, for example with particle effects or tree foliage.




A parent is any Node in a Hierarchy that has another node linked to it. Usually when a parent is
adjusted, all its children nodes get the same transform.

Physically-based Rendering (PBR)

An approach for materials and rendering that creates more accurate and predictable results than previous game rendering techniques, and works very well with dynamic lighting conditions (like time-of-day).


Any of the perceptually distinct units of sound in a specified language that distinguish one word
from another, for example p, b, d, and t in the English words pad, pat, bad, and bat.


A method of lighting a 3D world, the Phong lighting model applies three different types of lighting
to the vertex of every polygon. Phong lighting works by performing operations based on the normal of the polygon, the “normal” being an imaginary line drawn orthogonal (straight up from) the face of the polygon.


This term comes from aviation. Most game engines count from +90 to -90 degrees, starting out
pointed straight up, turning downwards and ending pointed straight down. Straight forward is 0 degrees.


Short for picture element. There are two common meanings: the pixels that Textures or Bitmaps are made of, and the pixels that are rendered onto your computer screen by the game engine.

Photoshop Document (PSD)

A bitmap file type used in game development. It is the main image format for Photoshop.


Developed as a patent-free alternative to GIF, Portable Network Graphics (PNG) format is used for
lossless compression and for display of images on the web. Unlike GIF, PNG supports 24‑bit images and produces background transparency without jagged edges.


Most game engines use polygons to make the surfaces of their objects. A polygon can be made
up of 1 or more triangles, like a quad is made of two triangles, a pentagon is made of three triangles, etc. Some engines support multiple polygon types, but triangles are the most common.

Power of Two

This means the numbers 2, 4, 8, 16, 32, 64, 128, 256, 512, etc. Usually this is used to describe the Texture sizes that a game engine requires in order to make good use of video Memory. An example pow2 texture size would be 32x64.




In systems that support multi-sided faces, polygons and faces are equivalent. However, most rendering hardware supports only 3- or 4-sided faces, so polygons are represented as multiple faces. When referenced as a quad it means this is a 4-sided face.



Random Access Memory (RAM)

A form of computer storage which stores frequently used program instructions to increase the general speed of a system. A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory.


The task of taking an image described in a vector format (shapes) and converting it into a raster image (pixels or dots) for storage in a bitmap file format. It refers to both rasterisation of models and 2D rendering primitives.

Ray Cast

The use of ray–surface intersection tests to solve a variety of problems in computer graphics and computational geometry. Typically a mouse cursor or crosshair will ray cast from a camera and provide the Entity ID needed to transform the object in 3D space.

Ray Tracing

A technique for generating an image by tracing the path of light through pixels in an image plane and simulating the effects of its encounters with virtual objects. The technique is capable of producing a very high degree of visual realism, usually higher than that of typical scanline rendering methods, but at a greater cost.

Real Time

A sub-field of computer graphics focused on producing and analyzing images in real-time. The term is most often used in reference to interactive 3D computer graphics, typically using a GPU, with video games the most noticeable users. The term can also refer to anything from rendering an application's GUI to real-time image processing and image analysis.

Render to Texture





Refers to the act of weighting a polygon mesh to a skeleton for the purposes of animation. The
“mesh” is the skin, and it is stuck to the “bones” of the animation rig, which form a skeleton that can then be manipulated by an animator to pose and animate the model.


An additive color model in which red, green, and blue light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additive primary colors, red, green and blue.


The roll axis (or longitudinal axis) has its origin at the center of gravity and is directed forward, parallel to the fuselage reference line.

Rotational Axis





The use of software that offers tools to push, pull, smooth, grab, pinch or otherwise manipulate a digital object as if it were made of a real-life substance such as clay.




The term skinning usually refers to assigning bone weights to the vertices of the model.

Smoothing Groups

A group of polygons in a mesh which should appear to form a smooth surface. Polygons in a mesh that should appear to be smoothly connected, smoothing groups allow 3D modeling software to estimate the surface normal at any point on the mesh, by averaging the surface normals or vertex normals in the mesh data that describes the mesh.



Splat Maps








Scalable Vector Graphics (SVG)

An XML-based vector image format for two-dimensional graphics with support for interactivity and animation.




A texel is each pixel of a texture during the time the texture is being processed by the game engine After the engine performs calculations to project the texture onto polygons, the texture pixels are transformed into texels. Then the engine renders the scene, and at that point it transforms those texels into screen pixels.

Texture Atlas

An atlas describes the method of packing many separate textures together into a single texture. Other common names for this are “decal sheet”, “packed texture.”

Texture Baking

Baking is the process of transferring details from one model to another. The baking starts a certain distance out from the model (usually a low-resolution model for game use), and casts rays inwards towards another model (usually a high-resolution sculpt).

Texture Compression

Compression is a technique to use larger or more textures in the same amount of memory and graphics bus bandwidth.

Texture Coordinates

Coordinates, also called UVs, are pairs of numbers stored in the vertices of a mesh. These numbers are often used to stretch a 2D texture onto a 3D mesh, but they can be used for other things like coloring the mesh, controlling the flow across the surface, etc.

Texture Filtering

Filtering is used whenever a texture is altered by the game engine to eliminate jagged edges and shimmering pixels.

Texture Types



















A generic facial image that can be used to describe a particular sound. A viseme is the visual
equivalent of a phoneme or unit of sound in spoken language. Visemes and phonemes do not share a oneto-one correspondence. Often several phonemes correspond to a single viseme, as several phonemes look the same on the face when produced.


A value on a regular grid in 3D space. As with pixels in a bitmap, voxels themselves do not typically have their position explicitly encoded along with their values. Instead, rendering systems infer the position of a voxel based upon its position relative to other voxels.




Has its origin at the center of gravity and is directed towards the bottom of the aircraft, perpendicular to the wings and to the fuselage reference line. Motion about this axis is called yaw. A positive yawing motion moves the nose of the aircraft to the right. The rudder is the primary control of yaw.




Known as depth buffering, is the management of image depth coordinates in 3D graphics, usually done in hardware, sometimes in software It is one solution to the visibility problem, which is the problem of deciding which elements of a rendered scene are visible, and which are hidden. The painter's algorithm is another common solution which, though less efficient, can also handle non-opaque scene elements.


A phenomenon in 3D rendering that occurs when two or more primitives have similar or identical values in the z-buffer. It is particularly prevalent with coplanar polygons, where two faces occupy essentially the same space, with neither in front.

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