Glossary of 3D Terms

1-sided
When a polygon is created, unless otherwise set up, it will have only one side.
If you were to look at a playing card, it has a front and a back. A 1-sided
polygon only has a front, and therefore only one surface normal.

2D Map
Two-dimensional map consisting of either a bitmap or a procedural map. An
object using a 2D map needs texture coordinates. See UV for further details.

2-sided
Like a playing card. A polygon that has a front, and a back, is 2 sided. A 2sided polygon will have two surface normals, facing opposite directions.

3D
A three-dimensional medium, display, or performance, especially a cinematic
or graphic medium in three dimensions.

3D Accelerator Card
A graphics card specifically designed for 3D graphics. LightWave uses a
system of 3D graphics called OpenGL and your graphics card must support
this.

3D map
Three-dimensional map either built up from multiple layers of bitmaps or, more
often, generated in three dimensions with a procedural texture. These are
algorithms that can generate 3D maps resembling marble or wood, and when
applied to an object, the grains of the marble, and the fibers of the wood, will
be correctly mapped to the surface in all three dimensions. If you split a 3Dmapped cube in two halves, the cross section surface will match the
neighboring faces. A 3D map does not require texture coordinates.

3D Object
Anything with a position and a representation in 3D space. Some objects have
a special role, for instance a camera or a light, while others serve as controls
for other objects, for instance splines or manipulators. The most common 3D
objects are geometric objects, which can be classified according to whether
they are polygon meshes, surfaces, curves, implicit objects, or nulls.

3D Shutter Glasses
3D glasses made with electronic liquid crystal shutters. They are powered by
the computer they are attached to and use this power to turn on and off the
liquid crystal in each of the lenses creating a 3D effect, instead of the usual 2D
display a computer monitor can offer.
3DS
Aged file format used by Autodesk 3D Studio and discreet 3d Studio max for
three-dimensional scenes. It contains geometry, textures, lights and cameras
as well as animation data.

Absolute Coordinates
The location of a point in terms of distances and/or angles from a fixed origin.
See Relative coordinates.

Adaptive Supersampling
A way of antialiasing the surface of an object by decreasing the oversampling
rate for those pixels that do not require the oversampling. The results of
adaptive supersampling are slightly more localized, and the computing time is
often shorter than other sampling methods.

Additive Mixing of Colored Light

There are two sorts of mixing of colors. One is called additive, or sometimes
transmissive and refers to the fact that the more red, green and blue you add
together the nearer to white your final color. This is the normal light scene for

LightWave or other graphics packages with output mainly through the medium
of a screen. Subtractive mixing indicates that the fewer colors you mix the
nearer to white you are and is used for reflective color, such as printed
material.

Additive opacity
Type of opacity that adds the background color to the material's color of the
transparent object.

Aggregate Object
An object that is made up of a number of other objects. A normal aggregate
object will be made up of primitives. A more complex aggregate object may be
made up of primitives, other aggregate objects, or both.

Algorithm
A problem-solving method that involves using a multi-step process.
A set of well-defined instructions given to the computer for accomplishing
some specific task.

Aliasing
When referring to pictures, aliasing is the effect that occurs when a line looks
jagged instead of smooth because of a contrast in colors. Usually, you can tell
when this happens because the line between the colors looks very jagged, as
if it were a flight of stairs, in fact it is often referred to as a "stairstepping"
effect. For contrast, see antialiasing.
Artifact or distortion, often referred to as 'jaggies', that occurs in a digital image
when not enough samples are taken to accurately represent straight lines and
smooth transition between highly contrasted edges. In a 3D rendered image,
the most common example is the stair-stepping effect seen along the edges of
objects.

Undesirable rendering artifacts in the form of jagged lines, edges, or surfaces

in computer images.

Alpha Channel
One of the four channels (or components) of information that make up every
pixel in an image. There are three channels for red, green, and blue (RGB)
and one alpha channel. The alpha channel is really a mask - it specifies the
transparency of each pixel, which allows portions of the foreground image to
reveal the background when two images are overlaid.
A channel of data in bitmapped images which stores the transparency of the
image, generally used for compositing. A 32-bit image has 24 bits of color
information and 8 bits of alpha. This allows 256 levels of transparency, from
totally transparent to absolutely opaque.

Alpha Matte/Image
Alpha matte/image generally refers to an image where the brightness of each
pixel is used to cut or partially dissolve out another image. These are generally
grayscale or black-and-white images, but the brightness values can also be
extracted from a color image.

Ambient Component
Part of the reflection-illumination model. A common surface shader parameter
that adds consistency to the color of an object's surface to simulate an
ambient light that reaches all points in a scene. An ambient value is
determined for individual surfaces. Scene ambience is multiplied with an
object's ambient color. If the scene ambience is set to black, nothing alters the
ambient color of an object except, of course, a light. The careful balance of
ambient and direct light sources is the key to convincing lighting. Global
illumination is an alternative to ambient light that is more accurate but takes
longer to render.

Ambient Color

The color of a surface where it is not directly illuminated. It is influenced by the

brightness and color of ambient light.

Ambient Map
Allows manipulation of the ambient component of an objects reflectionillumination model. Usually the ambient component is given a value near that
of the diffuse component.
Ambient Light
All-directional light illuminating every object uniformly from all sides.
General lighting that illuminates the scene, often without respect to direction. It
attempts to emulate the effect of light bouncing off of all objects to illuminate
all other objects, but is not a true simulation such as radiosity. A high ambient
light setting results in a washed-out scene, since no shadow can be darker
than the ambient light.

Ambient Occlusion
Ambient Occlusion is a shading method that is often used as a replacement to
Global Illumination because it can be much faster to render and easier to
control, but its not that accurate. It adds extra soft self-shadowing, which
gives the image more realism. A common technique is to render the scene in
normal way and then render out a separate Ambient Occlusion pass to make a
final composite.
Anaglyph
Moving or still pictures in contrasting colors that appear three-dimensional
when superimposed. Anaglyph works well for printed matter or computer
display, but color problems inherent in television displays (both PAL and
NTSC) result in poor 3D broadcasts.

Anamorphic Distort
An option referring to the width of a lens flare. When selected, the larger the
distort factor, the wider the lens flare will become.

Angle of Incidence
The relative angle between a lit surface and the light source. The more the
surface is turned away from the light source, the less light it receives and the
darker it becomes. When the angle of incidence is 90 degrees, the light shines
directly on the surface and it is illuminated with maximum intensity

Animate, Animation
The movement of elements through time and space. Also, the process of
creating and recording images that change over time. Everything in a scene is
represented by numeric values and, as such, animation is also the process of
changing these values - position, color, or any other property - over time. A
method of creating the illusion of life or movement in inanimate objects or
drawings. Through animation the artists drawing comes to life. The most well
known works are cartoon comedies, like Ren & Stimpy or The Simpsons, for
example.

Animatics
Preliminary animated versions of a final video or film presentation.

Animation Channel
Animation Channel refers to the different position, rotation, and scaling
settings an item can have in Layout. It can also refer to other envelope
elements like light intensity. See also motion channel.

Annotation
The process of inserting text or a special note, explanation or to provide
relevant detail to a surface, a rig or a point in your scene in LightWave.

Anti-aliasing
A method for blending harsh contours and preventing staircasing or
stairstepping. It is achieved by taking the surrounding areas into account when
assigning a color value to pixels lying on an object's contour.
Techniques to remove aliasing artifacts. Some examples are
oversampling/supersampling and filtering.
An algorithm which attempts to correct jagged, aliased computer images.
Blurring the image is one such method. A more advanced method is called
supersampling.

Antisymmetry Surface Restraint

The restraint of a surface tangent to the surface. This implies that the structure
is symmetrical about this plane, and the load on the implied symmetrical part
is equal to, but in a direction opposite to, the modeled part.

Aperture
The opening size of a camera lens. The greater the aperture, the smaller the
depth of field and the greater the amount of light entering the lens.

API
abbreviation for application programming interface.

Arc
Regularly curved open element that has a constant radius around a single
center point. A section of a circle.

Area light
A special kind of point or spotlight. The rays emanate from a geometric area
instead of a single point (entire surface uniformly emits light). This is useful for
creating soft shadows with both an umbra (the full shadow) and a penumbra
(the partial shadow).
Array
A set of elements put together into a single entity. A pixel array is an ordered
set of colored elements used for display purposes. In a 3D program, the array
tool is usually used to create ordered copies of an object within 3D space. This
tool is so named because it creates arrays of objects (creates an ordered set
consisting of multiple copies of the same object).

Aspect Ratio
A description of the proportion of an image by comparing its width to its height.
35 mm slides have the aspect ratio of 4:3 (1.33:1). Images become distorted if
forced into a different aspect ratio during enlargement, reduction, or transfers.
It should not be confused with the pixel aspect ratio, explained further on.
The proportion of screen width to screen height. NTSC video has an aspect
ratio of 4:3, or 1.33 to 1. Other common aspect ratios are 16:9 (1.78 to 1) for
high definition video, and 1.85 to 1 for widescreen theatrical 35mm film. The

number of pixels in an image is independent of the aspect ratio, and need not
even be whole number multiples of the aspect ratio. See pixel ratio.

Atmosphere
In LightWave, a volumetric effect that simulates reduced visibility in air over
distances.

Attenuation
When light travels through air its strength diminishes with the distance. The
further the light travels, the dimmer the light. In real life, the light attenuates by
the inverse square of the distance. This means that if attenuation is turned on
for a light only the geometry in its proximity will be lit. Not only is this more
realistic for your renderings, it also helps speed up rendering time since only
the geometry close enough to be affected by the light needs calculation time.
See also Decay.

Attribute
A property of a 3D object that can be adjusted. Attributes are sometimes called
parameters, and they are usually animatable. Attributes are found within
nodes. Examples of attributes include the radius of a Sphere and its position in
X, Y, and Z axes.

AVI
A popular file format that combines video and audio. It stands for Audio Video
Interleave.

Axis of Motion
In 3D space, the line that an object follows during movement.

Axis of Rotation
In 3D space, the line that an object rotates around.

Axis, Axes
The reference for describing the origin and position of an object in space,
displayed by intersecting straight lines. By using two axes, a plane is
determined; for example, the XY plane is defined by placing the X and Y axes
so that they intersect at the global center (point of origin). Three dimensions
are determined by using three axes: X, Y, and Z.

B rep
Slang for boundary representation

Backface Culling
A process included in most 3D graphics pipelines, backface culling eliminates
triangles facing away from the camera. This is most efficiently performed by
checking the orientation of the triangle normal in relation to the camera. The
technique ignores geometry seen from behind so that only the fronts of objects
that are facing the camera are rendered. Both faces of an object are rendered
by default; that is, the ones whose normals are facing the camera as well as
those that are not. You can choose which faces of the object you want to
render as part of the rendering options: front, back, or both faces. Back culling
(rendering only the front) can improve performance because less geometry
needs to be rendered.

Backface Elimination
See backface culling.

Background Color
The color that occupies all space not occupied by text, images, or any other
objects. By default LightWave's background color is black.

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Ball
Another name for a sphere. Basically, a ball is a 3D circle or oval created by
user-defined dimensions and settings.

Bandwidth
How much information a network can carry. Think of the network as a highway,
and each message as a car. The more lanes in the highway, and the higher
the speed limit, the more traffic it can carry. So the wider the bandwidth of a
network, and the faster its speed, the more information it can carry.

Banking
This is when an object following a path rotates about the path when it changes
direction.

Bank Shot
A shot in billiards in which the player causes the cue ball or an object ball to
rebound off a cushion. A shot in basketball in which the ball glances off the
backboard before reaching the basket. Also a shot fired during a heist.

Barn Doors
The flaps on the front of a movie light to assist in limiting the beam of light.

Baud
Bits per second. Hence kilobaud or Kbaud, thousands of bits per second. The
technical meaning is `level transitions per second'; this coincides with bps only
for two-level modulation with no framing or stop bits. Most hackers are aware
of these nuances but blithely ignore them.

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Bend
To deviate from a straight line or position: The lane bends to the right at the
bridge. To assume a curved, crooked, or angular form or direction: The
saplings bent in the wind.

Bevel
A method of eliminating sharp edges from objects by extending an objects
faces.

Bzier Curve
A technique for creating curves that was attributed to and named after a
French engineer, Pierre Bzier, who used them for the body design of
Renault's cars in the 1970s.
A type of spline or patch that uses adjustable tangent handles to control the
curvature near each control vertex. Named after Pierre Bzier, an engineer at
the Renault auto company in the 1960s. Bezier patented the technique based
on earlier work by Paul de Casteljau.

Bilinear Filtering
Blurring the pixels in a bitmap when it is zoomed in so that it seems smoother
than it really is

Bilinear Intensity Calculation

A high-speed algorithm for generating shaded faces. Used in Gouraud
shading and Phong shading
Binary Space Partition
Also known as BSP, this is a technique used in real-time rendering for
resolving in which order polygons should be drawn. The technique requires
that a so-called BSP tree is built before the scene may be rendered. As this
build process is very costly in terms of execution speed, BSP trees cannot
usually be calculated in real-time and thus essentially only support highly

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Bit
The building blocks of computer data. Has either the value of 1 or 0 (current or
no current). Bits can be grouped together to carry larger values.

Bitmap
Two-dimensional monochrome raster image. A bitmap is a black and white
image marking boundaries. It is often used for clip maps in LightWave.
A still image produced by a fixed matrix of pixels. Examples of bitmap file
formats: .BMP (Microsoft Bitmap), .GIF (Compuserve Graphics Interchange
Format), .JPG (Joint Photographic Experts Group), .TIFF (Tagged Image File
Format), .TGA (Truevision Targa), .PNG (Portable Network Graphics).

Blade
A thin plane placed in front of a light to cast a shadow, taking light off of an
object. A device to create a shadow.

Blending
The mixing of two (or more) textures into one final texture that is displayed in
rendering, or the final step in making a margarita.

Blitting
The copying of a virtual frame buffer to the displaying screen.

Bone Hierarchy
Bones can be arranged to build a Bone Hierarchy, also called a Skeleton. The
hierarchy defines how the movement of one bone affects other bones (up and
down the hierarchy). If you then also add Constraints to the bone hierarchy,
you have a Rig.

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Bones
The basis of movement for a model. Bones define parts of a model and how
they move in relation to each other. Bones can be created in any object, even
those which would normally be considered to be inanimate, to give life to that
object and make it move smoothly.

Boolean
A mathematical system developed by George Boole that expresses logical
relationships between things. The results in a Boolean operation can be either
true or false. Boolean is used in 3D to add, subtract, and other operations that
involve Boolean calculations.

Boolean Object
In computer graphics, a Boolean is a compound object which combines two
objects, called operands. It is used in modeling to join objects seamlessly and
to cut holes. There are three operations: union, intersection, and subtraction.
Union merges the two objects into one, continuous surface. Intersection
creates an object from the overlapping volumes of the two operands.
Subtraction, or difference, is the most common operation: one operand is a
tool to cut a hole in the other operand. The term Boolean is from George
Boole, the English mathemetician who developed symbolic logic.

Boolean Operations
A modeling technique that uses two objects that are overlapping to create a
new object. There are three kinds of boolean operations: subtraction, union
and intersection. By taking the first shape and subtracting/unifying/intersecting
it to the second - a new shape is created.

Boom Shot
A camera move. Usually describes a shot in which the camera is mounted on
a crane. The camera can move in all axes of movement.

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Boundary Representation
A polygonal mesh representation. A polygonal mesh is, most commonly, a
simplification of a shape using facets to describe curvatures. Its surface, or
boundary, is built up from several faces that describe the shape. If it is a
polyhedron the polygon model can be identical to the shape, whereas an
organic shape is represented by a more or less simplified version that mimic
the curvature using facets with variable density.

Bounding Box
A cubic shape that exactly circumscribes a (more complex) 3D model and is
used to optimize three-space calculations like ray tracing. By representing a
more complex shape with a box, possible ray intersections can be investigated
much more swiftly. Also used to represent complex objects for proxy animation
and setup to speed up operations.

Bounding Volume
A way of speeding up ray tracing operations involving intersection calculations,
by inscribing a complex mesh in a considerably less complex shape like a box
or sphere. Often used when rendering must be done in a short amount of time.
Instead of having to check the intersection of a more complex mesh, like a
space ship or a teapot, the bounding box works as a stand-in, with the same
maximum height, width and length as the mesh it substitutes for. Therefore a
possible ray intersection can be either ruled out (if the ray doesn't pass
through the bounding box, it doesn't pass through the mesh either), or let a
more time-consuming algorithm take over working with the complex mesh
instead.

Box
Another term for a cube. This is a six-sided 3D object that can be thought of
as a 3D square or rectangle. Boxes are created based on user-defined input
as to the dimensions and locations desired.

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BSP
abbreviation for Binary Space Partition.

B-Spline
A free-form curve that is defined with parameters in which each separate
vertex on the curve has an influence over a portion of the curve. In 3D, Bsplines allow a user to control a curved line on two axes at once.
Basis spline; a very smooth curve controlled by three or more control vertices
(CVs). The B-Spline always intersects the first and last CV, but is usually only
influenced by the others.

Bump Array
See also: array. The purpose of a bump array is to create an ordered series of
bumps in a surface. This tool means exactly what its name implies - an array
of bumps.

Bump Map
Creates the illusion of three-dimensionality of a surface (protrusions and
cavities) by recalculating the normals of the object, without changing the mesh
itself. It is very common in 3D renderings and suitable for creating effects like
wrinkles, creases, crumples, cracks, seams etc. The silhouette of a bump
mapped object is a give-away since, in these areas, it is obvious that the mesh
is left unaffected (if trying to create an orange by using a perfect sphere with
an orange peel texture applied to it for bumpmapping will still have a
impeccably round silhouette). In LightWave areas in a bump map that are
black are unaffected and areas that are white are raised.

Bump mapping
A technique where at each pixel, a perturbation to the surface normal of the
object being rendered is looked up in a heightmap and applied before the
illumination calculation is done. The result is a richer, more detailed surface
representation.

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Byte
8 bits. Multiples of bytes make up the terms kilobyte (1024 bytes), megabytes
(1024 kilobytes) and gigabyte (1024 megabytes).

CAD
Computer Aided Drafting (or Design); A system that lets a designer use a
computer screen instead of a drafting table to make plans and blueprints.
Designers can use CAD for anything from the largest building to the tiniest
screw.

CAM
Computer Aided Manufacturing; the process of using a computer to create a
physical product from a computer-created design. CAM is usually used to
control robots that perform tasks that would be tedious or dangerous to human
workers. See also Rapid Prototyping.

Camera
An apparatus for taking photographs, generally consisting of a lightproof
enclosure having an aperture with a shuttered lens through which the image of
an object is focused and recorded on a photosensitive film or plate.
Nowadays, young technobods also use digital cameras, which use CCDs to
focus light and create a digital picture that can be seen and transferred to a
computer immediately. In LightWave terms, the camera is the conduit through
which your objects and scenes are turned into still images or animations.

Capping
Surface closing the upper and/or bottom side of an object such as a cylinder.

Cartesian Coordinate
A mathematical representation of Euclidean space. Every point can be
described by three coordinates (X, Y, Z) representing the position along the

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orthogonal X, Y, and Z axes. The point (0, 0, 0) is called the origin, which is the
global center of the 3D world.
A method of locating points in 2D or 3D space by measuring distances parallel
to intersecting straight-line axes. These coordinate axes are perpendicular to
one another, defining a 2D grid or 3D cubic lattice. First published by French
philosopher and mathematician Rene Descartes in the 17 th century.

Cartesian Space
A space in which positions are denoted by a three-coordinate system (x, y,
and z coordinates) relating to a central origin (0,0,0).

Catacorner
slanted across a polygon on a diagonal line; "set off in a catty-corner direction
across the vacant lot". syn: cata-cornered, catercorner, cater-cornered, cattycorner, catty-cornered, kitty-corner, kitty-cornered

Catawampus
All outtawhack.

Caustics
Light pattern created by specular reflection or refraction of light, such as the
patterns of light on the bottom of a swimming pool, or light through a glass of
wine.
The light patterns generated on a surface by reflected or refracted light rays.
Photon mapping is one implementation of this.

CD
Abbreviation for Cadmium. A soft, bluish-white metallic element occurring
primarily in zinc, copper, and lead ores, that is easily cut with a knife and is

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used in low-friction, fatigue-resistant alloys, solders, dental amalgams, nickelcadmium storage batteries, nuclear reactor shields, and in rustproof
electroplating. Atomic number 48; atomic weight 112.41; melting point
320.9C; boiling point 765C; specific gravity 8.65; valence 2. Also used to
designate compact disc storage media.

Center of Projection
The point in perspective projection where all projectors intersect.

Center of the World

Is the absolute center of a 3D space, represented by X, Y, and Z points (0, 0,
0). Also referred to as the Origin.

Center Point
A point that represents the center of an object. This point is used in some
programs for a point of reference for rotation and position. The center point of
a polygon is where the line representing the normal comes out from.

CGI
Computer-Generated Imagery. Its the application of the field of 3D computer
graphics to special effects. CGI is used in films, television programs and
commercials, and in printed media. Video games most often use real-time
computer graphics (rarely referred to as CGI), but may also include prerendered "cut scenes" and intro movies that would be typical CGI applications.
These are referred to as FMV (full motion video).

Chamfer
To cut off the edges of the geometry with a planar cut, creating a more blunt
shape, typically at a 45 degree angle; A beveled edge or corner between two
intersecting lines or surfaces.

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Child
An object whose movements are influenced by another object, called the
parent.
Chord Length Parameterization
See non-uniform parameterization

Clean Modeling
Refers to the practice of removing geometry from a model that is not wanted
or needed. Also refers to the use of proper geometry construction techniques,
such as creating continuous surfaces, minimizing narrow faces, and avoiding
small corner angles, that facilitates downstream processes.

Clipping
More often than not, much of the graphics drawn for a specific scene does not
fit into the viewport of the camera. Accordingly, those which fall outside of the
viewport must be clipped so as they are not drawn. Depending on the nature
of the application, there are two kinds of clipping: 2D and 3D. The earlier
simply compares each pixel against the extents of the rendering viewport,
while the latter technique uses the six sides of the view frustum to determine
whether a 3D vertex is inside the viewport or not.

Clone
This tool creates copies of an object based on user-defined parameters for
offset, motions, morphing, shadows, etc. This tool can be used to make
ordered sets of objects, but is different from the array command because not
all of the new objects will be exactly the same as the original.

Cloud of Points, or Point Cloud

A set of x-y-z coordinates obtained from a 3D scanner or digitizer. The data
can then be turned into a continuous surface and used as a 3D model.

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CODEC
Short for compressor/decompressor. This is the term used to reference the
way that software programs handle different movie files, such as Quick Time,
AVI, etc. The CODEC can control image quality, and can assign the amount of
space given to the movie file. First, a multimedia publisher uses a codec to
squeeze more sound and video into less file space. These compressed files
are easier to fit on a CD-ROM and transfer to your computer. Then, your
computer uses a codec to expand these files back to their original size and
replay them on your screen.
Coincidence
Refers to geometry that occupies the same spatial location. For example,
coincident vertices are points that occupy the same x, y, and z coordinates.
Coincident lines can have differing lengths while one occupies the same
location as the other.

Color Bleeding
When the color from one surface reflects onto another surface.

Color Depth
The number of bits used to represent a color. For example an 8-bit image uses
2^8=256 colors. The bits build up the three primary colors red, green and blue.
The bits are divided into red, green and blue (optionally an alpha channel as
well). For example a 16-bit color could look like this R: 4-bit (16), G: 4-bit (16),
B: 4-bit (16), Alpha: 4-bit (16) - together they add up to 16-bits. The number of
bits can also be unevenly divided (R:5, G:5, B:5 Alpha:1).
This is why a GIF (max 8-bit=256 colors) only sports 128 colors if it is
transparent (1 bit is used to represent transparency in the alpha channel, 7bits = 7^2=128).
The following table indicates the number of colors an image can have.
8-bit = 2^8 = 256
16-bit = 2^16 = 65536

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24-bit = 2^24 = 16 million

32-bit = 2^32 = 4.3 billion
You should also be aware of FP, or HDR images.

Color Model
A system used to specify colors. In LightWave, you can set color according to
the following color models: RGB (red, green, blue), HLS (hue, lightness,
saturation), HSV (hue, saturation, value) or integer values.

Color Keying
An old technique of combining two images by replacing one color of the
destination image by the corresponding pixels of the source image.

Column Interleaved Format

The 3D image format used by the VR-4200 projector. Left and right view
image data are encoded on alternate columns of the display.

Compiled Vertex Array

Array of geometry data on a vertex level that is optimized (compiled) for faster
access by the graphics card. (Note that this is an OpenGL term, and is known
by other names in other APIs.
Compositing
A layering technique that places one image on top of another, properly taking
transparent pixels, apparent depth, shadowing and other elements that make
up an image into account.
The combination of two or more images to create a new image. A simple
example would be a foreground character superimposed over an
environmental background.

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Concentric
Having a common center or origin point with varying radii.

Cone angle
The angle at the peak of a cone.

Conic
Element having the form of a cone.

Conic Section
Curve formed by the intersection of a plane with a cone.

Constraints
Values in a geometric model that define relationships, i.e. a line is tangent to a
circle. Constraints are often used to drive parametric or variational geometrybased systems; the algorithms used to work with constraints are known as
constraint management.
Limitations applied, particularly to the movement of an object.

Continuous LOD
Short for continuous Level-Of-Detail, this method is based on the observation
that 3D objects located far off in the distance may be approximated by simpler
versions without loss of visual quality, thus increasing the rendering
performance. The "continuous" refers to having the algorithm constantly
recompute the detail level of the 3D object depending on the distance to the
camera instead of having a pre-computed set of objects to choose from.
Computationally expensive, this method is most often used in height field
rendering applications. LightWave can approximate continuous LOD by using
an Object list.

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Convex Hull
The skin created by enclosing all the extreme points of a 3D object.

Convex Volume
A convex volume can be defined as a volume whose every corner can be
visible from all other corners in the same volume. Another way of defining the
convexity is that all faces in the volume will be lit by a point light located
anywhere within the volume.

Cookaloris
A device put in front of a light, to break the light up. Common cookalorises look
like leaves on trees, or blinds on windows.

Cookie
A small, usually flat and crisp cake made from sweetened dough. Also, slang
for a cookaloris.

Coons Patch
A free-form surface that is determined by the four curves that define its edges.

Coplanar
Refers to two or more entities that lie on the same plane. Two planar surfaces,
for example, that lie on the same 3-dimensional plane are considered
coplanar. If these coplanar surfaces share a common edge, it is recommended
that they be joined into a single surface.

Cross Product
Using two vectors to calculate a normal of those two.

24

Cross-Section
A view of the interior of an object as it is sliced along a plane.

Cubic Image Map

One of the many methods of applying a texture to a surface. This method
applies the texture to an object as it would apply the texture to a cube. There
are many other methods of texturing objects, such as Planar and Cylindrical
image mapping.

Curvature Continuity
A curvature continuity with smooth transition of the edges of two meeting
surfaces (the highlights of the two surfaces blend together seamlessly, forming
the illusion of a single shape). If a curve (or surface) has tangent continuity
and both the 2D curves (or 3D surfaces) have the same radius a very smooth
transition is created with curvature continuity. Curvature is defined as 1/radius.
Hence, small radius equals high curvature

Curve
In computer graphics, there are different ways of representing a curve, for
example using NURBS and Bezier curve, so see those terms, okay?
Curve Parameterization
See parameterization

CVA
Abbreviation for compiled vertex array.

Cylindrical Image Map

One of the many methods of applying a texture to a surface. This method

25

applies the texture to an object as it would apply the texture to a cylinder.

There are many other methods of texturing objects, such as Cubic and Planar
image mapping.

Decay
Phenomenon where the light intensity decreases with the distance. The further
away from the light source, the less intense are its rays. In the real world the
decay is proportional to the inversed square of the distance (quadric decay),
but there is also directional (one-dimensional) decay (slower than in real life)
as well as cubic decay (faster than in real life). See also attenuation.

Decompression
Process of returning a compressed file to its full size (or a diver to the surface
if he has been on a particularly deep dive).

Default Unit
The Default unit is the unit of measure (ex. meter, feet, etc.) that is assumed,
usually when no unit of measure is entered with the numeric data. In Layout, it
is determined by the setting on the General Options tab of the Preferences
panel. In Modeler, the setting is on the Display Options panel.

Depth buffer
Same as a Z-Buffer.

Depth Cueing
The process of reducing the apparent sharpness of an object the farther away
it is from the viewer or camera. This often enhances the perception of depth.

26

Depth of Field
The total distance, on either side of the point of focus, which, when viewed
from an appropriate distance, APPEARS sharp in the final print.

Depth Sorting
Sorting all triangles in the world depending on diminishing depth (lower and
lower z-value) so that when they are rendered, the triangle closest to the
viewer is obscures those behind it.
Deskew
Process used to remove skew or distortion through a small angle rotation.

Diffuse color
The color of a rough or matte finish surface.

Diffuse Component
Part of the reflection-illumination model. The diffuse is concerned with the
amount of light that is reflected back.

Diffuse Light
A component of the reflective model that is the result of direct illumination.

Diffuse Map
Replaces the diffuse component of the reflection-illumination model, basically
giving the illusion of being painted onto the surface. To create a material
resembling wood or marble, this map is used. Generally, when you talk about
the "texture map" in an application, this is the map actually referred to.

27

Dimension
A measure of spatial extent, especially width, height, or length.

Directional Light
Another name for a distant light.

Director of Photography
The person on a movie set that determines how to photograph the movie.

Disc
A shape that is referred to in mathematics as a cylinder. This shape is
composed of two circular or oval-shaped bases and the space contained
between those bases. In other words, a disc is like a stack of circles with set
parameters defined by the user.

Displacement Map
Can be used to modify the actual mesh (as opposed to the bump map) to
create wrinkles, creases, crumples etc. The displacement map will need a
more complex mesh to create the same effect as bump mapping, but has the
advantage of allowing more thorough close-ups, since the surface is actually
deformed and not just simulated as being so.

Displacement Mapping
An alternative technique in contrast to bump mapping, normal mapping, and
parallax mapping, that uses a heightmap to cause an effect where the actual
geometric position of points over the textured surface are displaced along the
surface normal according to the values stored into the texture.

28

Display Types
Ways of displaying objects in a viewport. Display types are available only for
geometry views. The available display types are Bounding Box, Vertices,
Wireframe, Front Face Wireframe, Shaded Solid, Textured Shaded Solid and
Textured Shaded Solid Wireframe. Display types do not determine the quality
of the final render.

Distant Light
A light with color, intensity and direction. All rays emitted from a distant light
are parallel, and therefore it has no obvious source.
Distant lights can be used to simulate point lights from a great distance
(whose rays can be approximated to be parallel) like for example the sun. The
intensity from a distant light does not decay.

Dithering
Creating the impression of having more color on the screen than there actually
are by plotting pixels (with a limited amount) of different colors next to each
other.

DOF
Abbreviation for depth of field.

Dolly
To move the camera along its line of sight (in a straight line following the
imaginary path between the actual camera and its target point).

Dongle
A hardware lock used to prevent the piracy of LightWave. A common question
from people who have pirated LightWave is "what's a dongle?"

29

Dopesheet, Dopetrack
Two animation tools in LightWave that allow the user to better organize his
keyframes.

Dots per Inch, dpi

In a bitmapped image, the number of dots that exist within each inch of the
image. This number remains constant, so when you make an image larger, the
quality decreases, but when you make the image smaller, it appears to
increase.

Double Buffering
This is the process of using two frame buffers for smooth animation. While the
image of the first buffer is being displayed, the graphics controller can use the
second buffer to build or render the next image. Once the second image is
completed, the buffers are switched. Thus, the result is the appearance of
smooth animation because only complete images are displayed, and the
process of drawing is not shown. You can often now see Triple buffering in
graphics cards to allow an extra buffer for the next image in case there is a
problem.

DP
Abbreviation for Director of Photography.

DVD
A high-density compact disc for storing large amounts of data, especially highresolution audio-visual material. Abbreviation for digital video disc or digital
versatile disc. A DVD used solely for a computer is commonly referred to as a
DVD-ROM.

30

DWG
AutoCAD native file format. It can contain 3D data, but is hard to convert to a
LightWave-native format because of its construction. A DWG file is parametric,
that is to say it does not contain the objects themselves, but rather instructions
on how to build the objects. This makes it hard to translate if you do not
possess a license of AutoCAD. The solution is to either get one or get your
client to supply you the object in a different format, preferably OBJ.

Dynamics
The branch of mechanics dealing with the way masses move under the
influence of forces and torques. Increasingly used to drive animations by the
application of physical laws.
Automated or semi-automated procedural animation that simulates how
objects move in the real world, typically employing the laws of Newtonian
physics. Rigid body dynamics describe how objects respond to forces such as
gravity and collisions. Soft body dynamics additionally simulate how objects
deform when in motion.

Easing
The reduction in the acceleration or deceleration of motion to present a
smoother, more continuous movement. The shape of a function curve can
reflect this when using a spline interpolation.

Edge
A straight line connecting two points on a polygon. LightWave does not allow
you to select edges as discrete elements of a 3D object, but selecting the
aforementioned two points does the job.
The boundary between two faces of a mesh model. An edge is a straight line
connecting two vertices, and bounded by a face on either side.

Edge Loop
A particular method of modeling organic shapes with the edges of polygons

31

creating a loop or a flow around circular features around the eyes and the
mouth for example.

Effects Animation Broadly speaking, any animation which involves

special visual effects rather than character animation or simple transform
animation. Examples include particle systems and dynamics.

Environment Map
Map often used to simulate (faking) reflection of the surrounding world without
using ray tracing.

Euler Angles
Euler angles are one of the simplest methods of representing 3D rotations,
and generally also the easiest to visualize. An object's rotation can be
specified in terms of its yaw, pitch and roll, or rotation around the Y, X and Z
axis, respectively. Euler angles suffer from singularities in the form of so-called
Gimbal lock, however, and are also difficult to smoothly interpolate for
keyframe animation

Expression
Mathematical expressions that allow you to change the animation of an object.
You can also create constraints between objects using expressions or create
conditional animation. Expressions are very powerful for creating precise
animation and to create automated animation of things such as wheels.
A relatively simple statement in mathematical or computer programming
language, used to generate or manipulate data for animation. For example,
particle systems tend to rely on expressions to control the generation and
behavior of the system. An expression usually takes the form of an equation to
set the value of a parameter or attribute.

32

External Attributes
The position of the camera and the direction it's pointing.

Extrude
Creating a three-dimensional object from a two-dimensional shape by adding
a third dimension to it. You can also do this along a motion path or spline.
A simple process of converting 2D shapes into 3D. A copy of the 2D shape is
moved perpendicular to the original, then connected to the original to create a
closed surface. For example, extrusion can be used to create renderable 3D
logos from 2D text shapes.

Face
The shape made up by the bounding point making a polygon. Faces can have
as many vertices as wanted, but only polygons having a shape of three or four
vertices can be made into sub division surfaces.
A renderable 2D plane. The narrowest definition of a face is a triangle, the
simplest possible 2D shape. A face can also be a synonym for polygon.

Face Normal
Also just known as the normal, this is a line perpendicular to the face that also
describes which way the face is pointing in a one-sided polygon.
Also known as polygon normal or surface normal. A visual indication of which
side of a face is renderable. Displayed as a line pointing out perpendicular to
the surface of a face. For a one-sided surface, if a normal is pointed away
from the camera, that face will not render.

Falloff
The volume starting at the outer rim of a spotlight's hotspot, decaying from full
intensity at the start to zero intensity at the outermost rim of the spotlight. The
less the difference (in angles) between the hotspot/falloff, the crisper the

33

shadows. If the falloff angle is much larger than the hotspot angle, the
boundaries of the area lit up by the spotlight will be fuzzy. NOTE: in real-life,
you are unlikely to find lightsources with a hotspot angle close to the falloff
angle. Normally, the edges of shadows are not too crisp, but smooth, so a
word of caution might be in place to prevent overusage of sharp edged
shadows.

Field of View
(FOV) The angle of the view frustum. The wider the FOV, the more you see of
the scene. Human eyes have a FOV of about 50 degrees, and normally virtual
reality application use similar values to resemble real life.

Field Rendering
An option that causes the program to render two interlaced fields of
information. This is in contrast to rendering only one (full frame) and makes
moving objects appear to move more smoothly. Used for projects that will play
back on television monitors that display 50 or 60 interlaced frames per
second. Fielded animation is not useful for animations designed to be display
on computer monitors. See Fields.

Field Sequential 3D Video

The most common format for 3D video. Left and right image data are encoded
on alternate field of the standard video signal.

Fields
Interlaced images (video) consist of two fields that are combined into one
frame. Each field contains half the scan lines (either even or odd) and is a
separate pass. This is more common to render to for TV broadcast. Horizontal
movement of items will strobe without rendering to fields.
Interlaced sub-frames in a video frame. There are two fields in each video
frame; field 1 is composed of all odd numbered scanlines (rows of pixels).
Field 2 is composed of all even numbered scanlines. Rendering fields

34

improves the smoothness of fast-moving objects when viewed on interlaced

video formats.

Fill Light
Additional light sources assisting the key light in a scene. Usually they are less
intense than the key light and created using point light or spotlight.

Fillet
To round off the edges of an object with a round shape. Think "router", use
"Rounder" in Modeler to achieve it.

Fill-rate
The amount of pixels from a texturemap (texels) that is rendered per time unit.
Measured in texels/second.

Filter Opacity
Type of opacity that uses a color to simulate object opacity.

Finger
A small strip placed in front of a light to cast a discrete shadow.

FK
Abbreviation for forward kinematics.

Flag
A device placed in front of a light to create a shadow. A flag is large, to remove
light from a large area.

35

Flat Shading
Shading technique where all individual faces in a mesh are assigned a single
color value based on the orientation of their face normals.
A rendering method which does not smooth any edges among faces, resulting
in a faceted look. Also known as constant shading.

Flatness
Flatness is used as a threshold in determining if a polygon is non-planar. A
flatness of 0 percent means the polygon is absolutely flat. Flatness is
computed as percentage deviation from a triangle (the ideal plane) formed
from the first two and last vertices of a polygon. All of the other points are
measured relative to this plane. The largest deviation is divided by the total
size of the polygon to get a percentage that is the flatness value. For example,
if a polygon is 1 meter wide, 5% flatness means that no point will be outside
the ideal plane of the polygon by more than 5 millimeters. (1 x .005)

Floating Point (FP) images

Refers to images that do not use standard color depth models to represent the
colors contained in them, but rather an expression of the floating point value of
a color changing from 0 for black up to 1 for the brightest point in the image. A
mid-gray in such an image would be represented by R: 0.5, G: 0.5, B: 0.5.

Focal Length
The distance between the lens and the light-sensitive surface on the
backplane (the film in real-world cameras). The lower the focal length, the
more of the scene is visible. Focal lengths less than 50 mm is called wide
angle, while lengths greater than 50 mm is referred to as telephoto lenses.
The longer the lens, the narrower the field of view. Distant details becomes
more visible. The shorter the lens, the wider the FOV. More of the environment
is visible in the rendered image. To simulate the human eye, you can use
values of about 50 mm.

36

Fog
Simple yet effective graphical effect most often used in real-time graphics to
obscure the far plane, thus bounding the viewing distance of the application.
There are essentially three types of fog: table-based, vertex-based, and
volumetric. Fog values may also follow linear or exponential curves. It can also
be found in graveyards during a full moon on Halloween.

Foreground Image
The image closest to the camera.

Foreshortening
The apparent effect of viewing an object on its long axis that makes it seem
shorter. For instance, an arm pointing directly at the camera seems to lose its
length as does a road going directly away toward the horizon.
Formula-defined Shapes
Refers to shapes that are defined by using one or more equations. This
includes complex shapes such as aesthetic bottles or simple shapes such
hyperbolic paraboloids, oblate spheroids, prolate spheroids, or ellipsoids.

Forward Kinematics Animation

Figure positioning by joint angle specification. Like posing a toy action figure.
Animation method where the position of a child object in an articulated chain
are determined by the position and orientation of its parent object. For
example, in a hierarchical linkage of a human figure, when the torso (the
parent) bends over, the head (the child) moves along with it, but the head can
be turned without affecting the torso.
FOV
Abbreviation for Field of View.
FPS
FPS stands for Frames per Second. This is the main a unit of measure that is
used to describe graphics and video performance.

37

Fractal
A mathematical object that exists between dimensions. The most famous
fractal, the Mandelbrot set, can be represented as a flat image. However, its
boundary has infinite detail, so it is possible to zoom infinitely deep into the
image. For this reason it is considered a 2.5-D object.
Fractal algorithms are widely used in computer graphics to simulate complex
patterns such as those found in natural phenomena. For example, realistic
mountains can be generated using fractal values mapped to elevation.
Simulated clouds and other volumetric effects are commonly generated with
fractal algorithms. These algorithms are iterative, meaning they can be
calculated repeatedly to achieve higher levels of detail.

Frame
A single complete picture of an animation. A frame is a static image which,
when followed by other static images sequentially, gives the illusion of motion.
You can render to frames or to fields. One film frame is 1/24th of a film
second. One video frame is either 1/30th for NTSC or 1/25th for PAL.

Frame-Buffer
The memory a computer uses to hold one or more frames for later use.
The portion of a computer or peripherals memory that stores an image so it
can be displayed or recorded onto another medium, such as analog film.

Frame-Rate
The speed at which a frame of animation is shown, usually expressed in
frames per second. US TV is typically 29.97 frames, European is at 25 frames
per second and movies are projected at 24 frames.

38

Freeze
To convert from vector or interpolated geometry (splines, NURBS, subdivision
surfaces) to pure polygons. Even if the renderer supports NURBS or
subdivision surfaces, this freezing happens at render time, and is usually
definable to the level of polygon creation by the user.

Frustum
The part of a solid, such as a cone or pyramid, between two parallel planes
cutting the solid, especially the section between the base and a plane parallel
to the base. See view frustum.

Fudge
Slang, to fake it, or to stretch the normal rules.

Function Curve A two-dimensional graphic representation of animation

data. The value of a single parameter or attribute is displayed in the vertical
dimension of the graph, and time is displayed in the horizontal dimension. The
slope of the graph indicates the rate of change in the parameter. Steep curves
indicate fast changes or motion, shallow curves indicate slow change, and flat
horizontal lines indicate no change. Sometimes abbreviated to fcurve.

FX
Shorthand term for effects.

Gamma
The contrast curve of a recorded image. Increasing the gamma of an image
makes it appear brighter (more washed out); decreasing the gamma makes

39

the image darker (muddier). Gamma correction is applied at many stages of

the image creation process.

GCore (Geometry Core)

The engine in LightWave that handles all animation and modeling tools.

Generic Primitive
Simple 3D objects that most 3D programs can create easily. These objects
typically consist of spheres, cylinders, cubes and cones.

Geometry
The points of an object. These points are usually seen with objects that can be
rendered. For example, a cube's geometry is composed of eight points. By this
definition, a curve has geometry since it is also composed of one or more
points, whereas nulls have no geometry. Geometry refers to the positional
layout of points and polygons for an object. The mathematics of the properties,
measurement, and relationships of points, lines, angles, surfaces, and solids.

Gimbal-Lock
What happens when two axes of rotation line up, thereby making 3dimensional rotation impossible. Here's an easy illustration, take any object
with neutral rotation (0 degrees on heading, pitch and bank) and rotate in the
pitch 90 degrees. Now, try to rotate in the bank. This is gimbal-lock.

Gizmo
See null object.

Global Illumination
Unlike the local illumination, this method of generating images supports effects

40

not only linked directly to the light sources themselves. In real life, the intensity
of a surface not only depends on direct illumination from the light source itself,
but also from indirect illumination from surfaces being lit. First there is ray
tracing that can cast shadows from one object onto a surface, allow objects to
be reflected in shiny surfaces or refracted in transparent materials.
Then there is radiosity, the effect of reflected light. If you have spotlights
projected at the ceiling in a white room, the light would bounce back and light
up the entire room. However, this can only happen if the renderer supports
radiosity or other similar techniques, which ours does. Hurrah!
Family of algorithms wich, when determining the light falling on a surface, take
into account not only the light which has taken a path directly from a light
source (direct illumination), but also light which has undergone reflection from
other surfaces in the world (indirect illumination).
A rendering algorithm that attempts to simulate the transfer of light among
surfaces in a simulated environment. Compare to local illumination, in which
there is no calculation of bounced light, reflections, or refractions.

Glossiness
This option affects how spread out across a surface a highlight caused from a
light is. Low glossiness makes a spread out highlight while high glossiness
creates a more central, pinpointed highlight.

Glossiness Map
An image to control the glossiness of a surface. Bright values in the image
indicate more glossiness, dark values less.

Glow
Optical light effect that looks like a fuzzy disc around the center of a light
source.

41

Goal
An object used in IK to create a point where an object will always reach for.
This is used to make objects appear to have realistic motion. Also to score a
point in most sporting events.

Gouraud Shading
Developed by Henri Gouraud in 1971, this is a fast incremental shading
technique using bilinear intensity calculation to create smooth transitions
between the vertices in a triangle. It is most often used for lighting purposes by
computing the vertex normals in the polygon, calculating the light values for
each vertex, and then Gouraud shading the polygon. Even though it has
obvious advantages over flat shading, the facets in the mesh can still be
discerned. The placement of the highlight depends on the underlying
polygons.

Graphical User Interface

The graphical interpreter between man and computer allows a more intuitive
interaction with the computer. The window maker in UNIX, and Windows for
the PC are both GUIs. This way you don't have to be computer literate to the
same extent as if you should have to type all commands you wanted the
computer to perform.

Greeblies
English slang. This describes the non-such little details on objects, usually
mechanical objects. Those details such can be found on spaceships, in engine
rooms, etc. You can also use the words "didges", "nurnies" and "doohickies".

GUI
Abbreviation for Graphical User Interface.

42

Halo
Optical light effect that forms concentric circles around the center of a
lightsource. Often clearly visible around street lights after a rainy day.

HDRI
High dynamic range imaging. Its a set of techniques that allow a far greater
dynamic range of exposures than normal digital imaging techniques. The
intention of HDRI is to accurately represent the wide range of intensity levels
found in real scenes ranging from direct sunlight to the deepest shadows.
Acronym for High Dynamic Range Imaging. HDRI provides a more realistic
simulation of lighting than previous techniques. It stores a much wider range of
values to describe the brightness of pixels. Standard bitmap images can
typically reproduce a contrast ratio of about 1000 to 1. HDR images can
reproduce the full range of real-world light intensities, for contrast ratios in the
range of 100,000 to 1.

HDR Rendering or HDRR / HDR Lighting

HDR is abbreviation for High Dynamic Range. Its the rendering of 3D
computer graphics scenes by using lighting calculations done in a high
dynamic range. Specifically it refers to the new lighting model used to
illuminate 3D worlds. Video games and computer generated movies greatly
benefit from this as it creates far more realistic scenes than with conventional
lighting models.

Heightmap
A grayscale digital image used to store three-dimensional data. Its usually
used in bump mapping, displacement mapping and for terrain mesh
generation. In a heightmap, the intensity of a pixel's color represents the
height displacement of the mesh's corresponding coordinate. A white pixel
represents the highest point in the map while a black pixel marks the lowest
point in the map.

43

Hidden
Any element that is not shown in the current rendering of the scene but still
exists.

Hidden Surface Removal

Algorithm for removing obscured polygons in a three-dimensional view space.
As opposed to the faster algorithm backface culling, the hidden surface
removal algorithm is able to sort out those polygons that are obscured by
another object. Another way of finding an obscured polygon is the z-buffer.

Hierarchy
A way of defining objects in relationship to each other (using a parent-child or
tree analogy). This relationship means that transformations, deformations, and
any other property of the parent object affect all child objects. This allows
separately modeled objects to be used in a scene as a single functional unit.
The movement of a parent affects the movement of the child, but you can
move the child without affecting the parent.
A structure of linkages among objects, necessary for animation of systems
with moving parts, such as characters and vehicles. Also known as parenting,
linking, and forward kinematics. In a standard animation hierarchy, child
objects inherit transform information from their parent. An object may have
many children, but can have only one parent. See also: inverse kinematics.

High Dynamic Range Image

HDRI is an image with a wide intensity range between the brightest and
darkest pixels. In typical 8/24-bit images, the maximum possible intensity
range is 255 times brighter than the darkest gray pixel (with a value of 1).
Natural scenes and images rendered with radiosity can have dynamic ranges
from 10 to 10,000 times greater than this. Recording this information requires
use of an image format with higher precision.

44

Highlight
Reflection of a light source on an object's surface. The size of the highlight
(the area that shows the light source reflection) depends on the angle.
Consequently, multiple light sources results in multiple highlights. This is also
the specularity.

HLS Color Model

Hue, Lightness and Saturation: the three components of the HLS color model.
Hue refers to the position of the color in the spectrum, such as red, yellow, or
green. Lightness is the amount of white mixed in a color, such as the
difference between a pure red and pink. Saturation is the purity of the color,
such as the difference between a pure red and a dusty rose - low saturation
means that there is grayer in the color.

Hotspot
The inner intense cone of light emanating from a spotlight.

HSV Color Model

Hue, Saturation, Value: the three components of the HSV color model. This
color model defines the hue and saturation similar to the HLS model. Value is
similar to lightness, as in HLS; however, a value of 1 represents a pure color
when saturation is 1, while a lightness of 1 yields white no matter what the
saturation. In both systems, 0 is black.

Hub, The
The Hub is a module in LightWave that allows the Layout and Modeler
modules use to synchronize information. It uses the TCP/IP protocol to
transfer information between modules.

Hue
The position of the color in the spectrum that describes the tone or tint of a
color, such as red, yellow, or blue.

45

HyperVoxel
Voxels are volumetric rendering effects. HyperVoxels are voxels that are
applied to nulls, points, or objects.

IK
Abbreviation for Inverse Kinematics.

Image instance
A copy or instance of a source image. Each time you use a source image, an
instance of it is created. You can have as many instances of the same source
as you need. You can then edit, crop, or even blur the instance without
affecting the original source image.

Image Map
An image that is applied to an object's surface.

Incandescence
The emission of visible light by a hot object. In LightWave, this is the
luminosity channel.

Incremental Shading
See interpolative shading.

Indirect Iillumination
Light that bounces of one surface and illuminates another surface. This can
only happen if the renderer supports radiosity. Does the LightWave renderer
support radiosity? Yes, of course!

46

Intelligentities
Intelligentities refer to LightWave's object format. The object format can
contain morphs, multiple layers, and independent pivot points on a per layer
basis.

Intensity
The strength at which the light source illuminate objects in the scene.

Interference Checking
The process of identifying if and where two or more pieces of geometry
(usually solids) intersect. When moving parts are involved, a kinematics
analysis is used to detect interferences.

Interlaced Scan
A video display mode which uses alternating fields to create the image. For
each video frame, odd numbered scanlines are drawn, followed by even
numbered scanlines. NTSC video is interlaced; most computer monitors are
not. See progressive scan.

Internal Attributes
The properties of the camera such as depth of field and line-of-sight.

Interpolation
The process used to estimate an unknown value between two or more known
values. In animation, interpolation is the process used to calculate values at
frames between two keyframes in a sequence.
Calculation of values between known values. For example, a smooth curve
can be described using just a few control vertices.

47

Interreflection
When a reflective object reflects another reflective object. For example, if you
place two mirrors in front of each other, the first one will display the second
one, who, in turn, shows the first one. In real-life, there is virtually no upper
limit of how many interreflections that may occur, whereas in 3D rendering,
one must set an upper limit to be able to render the scene. The default value
for LightWave is 16, but it can be lowered to 0, if desired, or up to 24 at a cost
in increased rendering time.

Inverse Kinematics Animation

Animation method that consist on positioning the ending limb of an articulated
chain to obtain an automatic pose or articulation of the whole chain.
Inverse kinematics is based on the following principles: 1. Joints are
constrained with specific positional and rotational properties.
2. Position and orientation of parent objects is determined by the position and
orientation of child objects.
Inverse kinematics is often easier to use than forward kinematics and user can
quickly create complex motions. However, it sacrifices some of users control
to the automation of the IK functions.
The process of determining the motion of joints in a hierarchical 3D object
given the desired start and end points, all the while obeying the laws of
kinematics. Think of it like the strings on a marionette puppet.
An intuitive alternative to standard hierarchical animation. The position and
orientation of parent objects are calculated from the position of the last child,
or end effector. The final position of the hierarchy is called the IK solution.

IR Transmitter
A device that sends synchronization signals to wireless shutter glasses.

Isometric View
Standard view in a 3D design where the top, front, and right side faces of a
cube are equally inclined to the screen surface.

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Item
An item in Layout refers to an object, bone, light, or camera.
JPEG (Joint Photographic Experts Group)
A widely accepted, international standard for compression of color images.

JPS
Stereoscopic JPEG file. JPS refers to a stereoscopic image file format that is
based on JPEG compression. Used by DepthCharge & other stereoscopic
imaging applications.

Junkyard
A special directory used by some studios to hold mechanical and non-organic
pre-modeled parts.

Key, Keyframe
A marker on the animation timeline that shows that a node's (e.g. an object, a
material or a light) attribute (e.g. position, color or intensity) in the scene graph
has been assigned a new value. Most animation programs interpolate the
node attribute values from one key to the next, creating smooth transitions - so
the user does not have to key every single frame. See also tween.
A frame from an animated sequence, at which a significant animation event or
change takes place. In computer animation, the animator defines the
keyframes and the computer generates the intermediate frames (process
called tweening).
In computer animation, a user-defined value for a parameter at a certain point
in time. The animator sets keyframes at significant moments, and the
computer software fills in all of the in-between values using interpolation.

49

Key-light
Dominate light source in a scene, normally created with a spotlight.

Kinematics
The properties of each 3D object that control its transformations. These
transformation properties are used to modify the selected object's scaling
(size), rotation (orientation), and translation (position) in X, Y, and Z in either
local and global space. Although related, kinematics are not to be confused
with inverse and forward kinematics for animation.

Kit-bashing
An expression taken from model making. The practice of using model kits to
give detailing to a larger project. This is still in use. It refers to the taking of
models that you have already made, to use in the creation of another, perhaps
even basically unrelated.

Lasso
One way to perform a selection of point(s), face(s), or polygon(s). This method
involves drawing a loop that encircles all of the objects that need to be
selected.

Latent Surfaces
Surfaces that are no longer visible after a Boolean or intersection operation
because they lie inside or outside the solid.

Lathe
Creating a three-dimensional object from a two-dimensional shape by rotating
it around an axis.

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Lattice
Either a way of deforming object using a lattice or a way of creating outlined
geometry.

Layer
A portion of a scene. Each layer consists of an object or multiple objects that
can be edited separately from the rest of the objects in a scene. A layer is
basically a building block for a scene and each layer contains separate blocks
for a final model.

Left-handed Coordinate System

Coordinate system where the positive part of the Z-axis goes away from the
observer (from the screen).

Lens
Part of the camera determining the optical characteristics of the image, such
as wide angle, fish eye and depth of field.

Lens Flare
Optical light effect made up from a number of bright discs. If the rays from a
light source reflects off the surface of a compound lens in a camera, it can
generate star-like patterns on the image. Lens flares tend to be a clich of bad
CG imagery, probably because of their short rendering time and flashy
appearance.

Level-of-Detail
This is a term that is talking about varying the amount of detail in an object
depending on the distance from the object to the camera. Example: A car for a
close-up would need to have every little detail modeled into it. Chrome,
bumpers, body seams, door handles, etc. But that same car, as seen from a
helicopter flying over a highway, might be able to be a simple cube with an
image map applied to it.

51

Level-of-Detail Control
The ability to vary the amount of details displayed in a graphics image to
improve performance. For instance, at a distance, models can appear as
simple 3D figures, but as users zoom in, a more detailed representation is
presented.

Light
In 3D graphics different types of lights are distinguished: ambient light, diffuse
light, point light, spotlight. There are also different terms used to simulate
material properties is illuminated: ambient component, diffuse component,
specular component. Incident light at a surface = reflected + scattered +
absorbed + transmitted. Light has a major impact of a rendered scene, but can
be hard to recreate.

Light Source
There are several different sorts of light sources used in 3D graphics to
simulate light: ambient, distant, linear, area, and spotlight. Special light effects
can be recreated such as volumetric light and glow. With radiosity, an object
with a high luminosity value can cast light as well.

Lighting a Scene
One of the ingredients of a nice rendering is realistic lighting. It is often good to
use one single light source (the key light) doing most of the work, helped out
by some additional, less intense lights (fill lights) that illuminates the
background of the rendered object to create a smoother look. Try to avoid
shadows with edges that are too crisp, since this is unusual in real life due to
radiosity.

Lighting Model
This is a model that uses a mathematical formula to decide what will happen
when light strikes an objects surface.

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Light-map
Luminance map generated (normally rendered) individually for each polygon
and then blended with the texture map to give the impression of light and
shadows falling onto the polygon without having to draw the effect on the
texture itself. The advantage of separating the light-map from texture map is
that if you should want to create a new "mood" for a scene you can set up new
lighting conditions for the scene, re-render the light-maps and apply them to
the mesh again, without having to redraw all texture maps.

Linear Patterning
The repetitive placement of the active pattern cell along a line, line string,
shape, arc, circle, ellipse, or curve element.

Line-of-Sight
LOS has become quite important in modern real-time interactive simulators,
especially for military purposes. To cut down on the polygon count and
increase rendering performance, programmers are often forced to employ
schemes to simplify terrain at large distances. This, however, has the
unfortunate drawback of warping the terrain, something that may make a
difference for long distance targeting purposes. Because of this, modern
terrain rendering algorithms such as ROAM tend to not simplify along the
primary LOS.

Local Coordinate System

As opposed to the world coordinate system the Local Coordinate System is
tied to a specific object. LCS are used, among other reasons, to simplify the
representation of complex objects by using several, different LCSes as
reference points for the object's vertices. It is also easier to transform the
object if you for instance can rotate it around its own "center of gravity" instead
of the origin of the World Coordinate System.

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Local Coordinates
Every object has its own origin, which is subordinate to the world coordinate
system (or other objects that are higher in the hierarchy). Local coordinates
are useful for determining positions of subordinate objects.

Local Illumination
A mathematical model capable of creating imagery where only direct
illumination is considered. Depending on the distance from the lightsource,
etc, each surface in the model can be given a color and intensity. This does
not include shadows, reflections and radiosity.

LOD
Abbreviation for level of detail.

Skin
Creating three-dimensional object from two or more two-dimensional shapes
and then extruding them along a path.

Loop
A continuous playback of an animation sequence.

LOS
Abbreviation for line of sight.

Low-poly modeling
To model using boundary representation using as few polygons as possible to
speed up rendering and processing time. Common style for games, but as
game processor engines get better, and computers faster, this is losing ground
as an art form.

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LScript
This is LightWave's built-in scripting language. LScripts can be installed and
used just like plug-ins.

Lumel
This is short for LUMinance ELement, the lumel is a pixel in a lightmap which
constitutes the color level in a specific area of the texturemap it is
superimposed upon.

Luminance
The black and white information (brightness, sharpness, and contrast)
encoded in a color. The amount of luminance contained in a color is directly
proportional to the amount of light intensity.

Luminance Map
A map that controls the luminosity channel of a surface.

Luminosity
Much like glow, luminosity is a measure of how much light a surface gives off
before any light strikes it. This effect can be used to create an object that gives
off its own light.

Magnet
This tool allows the user to move points in an object as if he or she was using
a magnet. It has an area of falloff where the strength of the magnet decreases
gradually to 0 giving a soft selection effect.

55

Map
An attribute that can be added to an object's surface to give it a certain look.
Projecting an image so that it covers the surface of an object or images that
affect the way an object looks. There are a variety of different maps used for to
create specific effects: diffuse maps, bump maps, opacity maps, etc. Maps
can be divided into bitmap-dependent texture maps and procedural maps. The
latter categories can, in turn be divided into 2D maps and 3D maps.
In 3D graphics, a map is an image used within a material. The purpose of a
map is to vary some material attribute across a surface. For example, a
texture map alters the color of an object, and a bump map simulates
roughness. 2D maps, including all bitmaps, require mapping coordinates,
which tell the renderer how to project the map onto the 3D object. 3D
procedural textures do not require mapping coordinates, because they are
volumetric.

Mapping
The process of making one image conform to the size, shape, and/or texture
of another image.

Material
There is an underlying material in any given surfacing, even though it might be
hidden underneath another texture map. By modifying the properties of a
material it can be made to look like wood, plastic, glass, metal etc, (hence the
name). The material is applied to the whole object. Also can be referred to just
as surface.
The surface properties of an object, such as color, reflectivity, and opacity.
Sometimes known as a shader.

Material Properties
The different properties of a material such as the ambient component, diffuse
component and specular component in the reflection-illumination model.

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Matrix
What is the Matrix? Much more than a mere programming term, or a movie
with Keanu Reeves. Matrices form the core of linear algebra and are important
tools in most engineering disciplines. In essence a two-dimensional array of
numbers, matrices are often used in transforms of different properties, such as
rotation, scaling, translation, deformation, and much more.

Memory swapping
The transferring of data back and forth between active RAM memory and disk.
When this happens, it can considerably slow down computing tasks such as
rendering.

Mesh
A really hip way of referring to your objects. Object made up from a number of
triangular faces.
A 3D object composed of triangular faces. A mesh object has no true
curvature. The appearance of curvature is achieved by increasing the number
of faces (level of detail), and by edge smoothing during render time.

Mesh Complexity
Term for describing the amount of information (amount of vertices, normals,
triangles etc) used to create an object. A higher mesh complexity needs more
memory and is slower to process

Metaform
One of the options used with the Subdivide tools. This feature does not divide
the polygons, rather it renders the edges of the polygons to be smooth,
making the object seem less faceted and cleaner.

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MIP-Mapping
Using a pyramid structure of a predefined fixed amount of differently sized
bitmaps (original size, original size/2, original size/4, etc) to speed up
rendering time by using less detailed textures for distant objects (represented
by only a few pixels on the screen), and the full-sized version of the bitmap
when the objects is closer to the observer. This way, moir-pattern can be
avoided.

Mirror
The mirror tool creates an exact mirror image of the selected object. This tool
is very useful for any symmetrical object, including faces, cars, and airplanes.
This tool literally cuts the modeling time of these objects in half. Can be used
to detect vampires.

Modeling
The process of creating a 3D scene consisting of objects and the applying of
mapping to those objects or of posing before a camera, sometimes with no
clothes on!
Construction of geometric objects in 3D scenes. Models describe the forms of
objects, but not their material properties or how they move.

Moir pattern
Optical pattern created due to aliasing. Usually appears as a swirling pattern
along a distant edge.

Morgue
A special directory, used by some studios, to hold already modeled organic
body parts. If you have modeled a good head, hands, ears, feet, etc. there is
no reason to model them again. These models are placed in a "morgue" for
other modelers to draw from.
Motion blur
The blurring of objects that move while the camera shutter is open, creating

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the illusion of movement. Motion blur also prevents strobing caused by toorapid of movement.

Motion Capture
A method used to input live movements into a computer with an external
source.

Motion Channel
Motion Channel is generally the same as Animation Channel, but refers only to
position, rotation, and scale (i.e., not light intensity.).

Motion Path
The line an object follows while in motion.

Movements
There are four basic camera movements: dolly, pan, orbit and truck.

Multiplex
The process of taking a right and left image and combining them with a
multiplexing software tool or with a multiplexer to make one stereo 3D image.
It's also where you go to see movies, usually has more than six screens.

Multi-Texturing
Applying two (or more) textures on the same face. For example, a polygon can
have a texture map resembling a brick wall and then be multi-textured with a
light-map to give the illusion of being lit.

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Natural Light
Light that exists in nature, such as sunlight or moonlight, depends on the time
of day, season and location on the Earth. The sunlight a clear day have an
RGB value of about R:250 G:255 B:175. For simulating overcast it might be a
good idea to add the blue component, whereas a sunset could be a little more
orange. As opposed to artificial light, the natural light has only one source (the
sun) and can most effectively be recreated using a distant light.

Node
The basic graph element used to represent distinct items (vertices, faces,
etc.). A signal coordinate in a grid, or finite element grid point used to describe
the structure. A node will lie on each vertex of a finite element, and additional
nodes may lie along element edges to define curved element topology.
In computer science, a node is an abstract container of information. Nodes
generally have attributes that store data. In a 3D graphics program, nodes are
connected together to form a network called a scene graph. For example, in
Maya, a primitive object such as a Sphere is made of three nodes, each
storing a different type of data: a primitive node, a shape node, and a
transform node.

Non-planar
Non-planar refers generally to a polygon where all points do not reside in the
same plane and can occur only with polygons using more than three points.
Non-planar polygons can cause erratic rendering errors. As an example, a
square piece of cardboard sitting upon a tabletop will become non-planar on
all vertices when lifted by a corner. Inherent in manipulation and deformation
of a model, non-planar "holes" can appear in the surface consistency of
models. Solutions include "tripling" (actually halving the quads diagonally) or
tessellating the polygons into triangles. As an example, a triangular piece of
cardboard sitting upon a tabletop will remain planar on one vertex when lifted
by any corner. Thus, when joined on their vertices, a group of triangles are
more robust when deformed.

Normal (Surface Normal)

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A normal is a vector that is perpendicular to a mathematical entity, such as a

line or a plane. In 3D, the normal can be used to define the direction a polygon
is facing, and is used extensively for backface culling and light computation.
What is normal?? A three-dimensional vector which is perpendicular to a
surface. Central to many computer graphics calculations.

Normal Mapping
An application of the technique known as bump mapping. While bump
mapping perturbs the existing normal (the way the surface is facing) of a
model, normal mapping replaces the normal entirely. Like bump mapping, it is
used to add details to shading without using more polygons. But where a
bump map is usually calculated based on a single-channel (interpreted as
grayscale) image, the source for the normals in normal mapping is usually a
multichannel image (with red/green/blue channels) derived from a set of more
detailed versions of the objects.

NTSC
(National Television Standard Committee). The most common video standard
in the United States and Japan. It has a frame-rate of 30 fps. 60 times per
second every other scan line is changed, resulting in smoother transitions. Its
pixel resolution is 720x486 with a pixel aspect of .9

Null
Non-renderable help-object used in modeling programs to simplify the
manipulation of 3D-objects and texture mapping.
NURBS
Non-Uniform Rational Basis Spline. A particular type of spline curve with
weighted control points. Compare to Bezier spline.

Orthographic projection
A flat, 2D view of a 3D object or scene. Technical drawings, blueprints and
floor plans are examples of orthographic projections. In 3D programs,

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orthographic views such as Front, Top, and Side are common. Orthographic
views are always aligned with the axes of the world Cartesian coordinate
system. They are necessary because 3D perspective views always introduce
visual distortions of object size, placement and/or distance.
An ortho view is unlike a perspective view, because an ortho view shows no
indication of distance or depth. In a perspective view, an object is displayed
smaller as it moves away from the viewer. Parallel lines appear to converge at
a vanishing point. Simulated rays of light from the 3D scene, called lines of
projection, all converge at the virtual camera lens.
In an ortho view, the size of an object in the view does not depend on its
distance. Two objects of the same size are drawn the same size on the
screen, no matter how far away they are. Parallel lines remain parallel, and do
not converge. The lines of projection are at right angles to the screen.

Nurnies
American slang. See greeblies.

Object
A model or construction that when placed in a scene will render to represent a
thing it represents from the real world.

Object Oriented Graphics

Different from bitmap format, this image type consists of objects that have
definite mathematical formulas behind them. These images always print at the
maximum quality specified by the printer, unlike bitmapped images that always
print at the same quality level. They can also be referred to as vector
graphics

Omni-directional light
Same as a point light.

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Opacity
The opposite of transparency.

Opacity map (or transparency map)

Makes the surface more or less transparent depending on the pixel intensity
(color value) of the opacity map where normally black is transparent and white
is opaque.

OpenGL
A 3D graphics API that includes capabilities for 2D imaging. Basically, OpenGL
is a set of instructions that can be used by a program to interpret images and
display them on the screen. LightWave uses OpenGL for all its displays.

Optical Light Effect

If the observer (or camera) looks directly at a bright lightsource it may appear
to glow. If the light is refracted through a lens or even your own eyelashes (try
squinting towards a spotlight!), the light will appear to form star-like patterns.

Orbit
To travel around a target - more commonly circular, but a comet's orbit can be
elliptical.

Origin
The world Origin is the absolute center of the LightWave universe. A local
Origin is the center of an object. Both are defined by the XYZ coordinates of 0,
0, 0.

63

Orthogonal
A view that displays a parallel projection along one of the major axes. In an
orthogonal view, the camera is oriented so it is perpendicular (orthogonal) to
specific planes: the Top view faces the XZ plane, the Front view faces the XY
plane, and the Right view faces the YZ plane. An orthogonal view eliminates
the effect of distance from a viewpoint, which provides a useful means of
locating points and objects in 3D space and is particularly helpful when
modeling objects in wireframe mode. An orthogonal view is in contrast to a
perspective view.

Orthogonal direction
There six different orthogonal directions in a three-dimensional space: up,
down, back, forward, left and right

Orthographic projection
Viewing system where the projectors are parallel and therefore doesn't create
a perspective with foreshortening.

Oversampling
See supersampling.

PAL
(Phase Alternating Line). The most common video standard in Europe. It has a
framerate of 25 fps. It is interlaced, which means that 50 times per second
every other scan line is changed, resulting in smoother transitions. The
resolution is 720x576 pixels and the pixel aspect ratio is 1.0667.

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Pan
To rotate the camera horizontally. As opposed to the orbit movement, the pan
rotates the camera around a single axis, as if it where mounted on a tripod.

Panel
In a 3D program, a screen that serves many functions such as informing the
user of errors, asking for user input, or informing the user of the state a
program is currently in. Otherwise known as a window or requester.

Parabola
A plane curve formed by the intersection of a right circular cone and a plane
parallel to an element of the cone or by the locus of points equidistant from a
fixed line and a fixed point not on the line.

Parallax Mapping
Also Photonic Mapping, Offset Mapping or Virtual Displacement Mapping. Its
an enhancement of the bump mapping or normal mapping techniques applied
to textures in 3D rendering applications such as video games. To the end user,
this means that textures will have more apparent depth and realism with less
of an influence on the speed of the game. It works with a heightmap.

Parameterization
Technique for assigning values to the edit points as they are spaced along the
length of a curve. Can be either uniform parameterization or non-uniform
parameterization (chord length). The first edit point on the curve had the value
0.0 (regardless of whether it is uniform or non-uniform) and the following edit
points are assigned greater values the closer they lie to the other end.

Parameters
Also known generally as properties, parameters are the "atomic" elements of a
property set whose values determine the behavior of something. A parameter
is one degree of freedom. You can set parameters in property editors.

65

Parent
An object that influences the motion of another object in a hierarchy, called the
child.
Parenting
The process of creating a hierarchical organization of objects in a scene. In
parenting, an object (called the parent object) is "parented" to another object
(called the child object). Parenting relationships can be nested to any degree,
so that one or more objects are the children of another object, which is in turn
the child of another.

Particles
2-dimensional objects typically used in large quantities to create effects like
rain and explosions.

Particle System
A type of procedural animation that reproduces the appearance of fuzzy
phenomena such as clouds or fire. Particle systems may also be employed to
animate many objects in a scene, such as a flock of birds.

Passive Polarized 3D glasses

3D glasses made with polarizing filters. Used in conjunction with a view screen
that preserves polarized light.

Patch
A deformable parametric surface, useful for creating curved objects. It can be
based on Bezier or NURBS mathematics. The curvature is controlled by the
position of control vertices.

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Penumbra
A partial shadow, as in an eclipse, between regions of complete shadow and
complete illumination, a fringe region of partial shadow around an umbra.

Perspective
A traditional art method of creating the illusion of three-dimensional form and
distance on a two-dimensional surface. Perspective provides a threedimensional view of the scene that indicates depth. In a perspective view,
objects appear to converge toward a central vanishing point, and objects
closer to the camera appear larger than those farther away. A perspective view
is in contrast to an orthogonal view.
Representation of a scene in which parallel lines are depicted as converging,
in order to give the illusion of depth and distance. Like an orthographic view, a
perspective view is a projection of a 3D scene onto a 2D screen. However, in
a perspective view, the lines of projection converge on a virtual camera, which
is the simulated point of view.

Perspective projection
Simulating three-dimensionality by using foreshortening that triggers the
human perception to interpret a two-dimensional image as if it was threedimensional. An object is drawn smaller and smaller the further it is from the
observer. This is achieved by using a center of projection to which all
projectors converge, as opposed to where the projectors are parallel.

Phong Shading
The most frequently used interpolative shading technique used today. It uses
a linear combination of three components - the ambient component, the
diffuse component and the specular component. The placement of the
highlight is less dependant on the underlying polygons as Gouraud shading
since Phong shading interpolates the normals on a per-pixel basis instead of
interpolating the light intensity based on the distance to the three vertices.

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Photon Mapping
A global illumination algorithm based on ray tracing used to realistically
simulate the interaction of light with different objects. Specifically, it is capable
of simulating the refraction of light through a transparent substance, such as
glass or water, diffuse interreflections between illuminated objects, and some
of the effects caused by particulate matter such as smoke or water vapor. It
was developed by Henrik Wann Jensen.
Photorealism
The process of generating computer images that mimic photographs.

Pitch
The amount that the camera or an object in the scene is tilted up or down. If
you nod your head yes, you are rotating your head in the pitch axis.

Pivot Point
A single point, usually in the geo-center of an object that is used for many
functions. It is the point that is addressed to locate an objects position in 3D
space. It is also the point around which all rotational moves are made and is
the reference point for transformations and scaling.
The center of an objects transforms, and the center of its local coordinate
system. An object moves, rotates, and scales relative to the location and
orientation of its pivot point. Also known as "anchor point" in some computer
applications.

Pixel
Short for PIcture ELement, a pixel is the smallest element of computer or
video display.
Abbreviation of picture element: the smallest possible element of a picture. A
digital image is defined by a discrete number of pixels arranged in a 2D grid or
mosaic. Many very small pixels blend together in the human eye and brain to
give the illusion of a continuous, unbroken image.

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Pixel Shader
A real-time shader application. A graphics processing function that calculates
effects on a per-pixel basis. Pixel shaders are used to compute properties
which, most of the time, are recognized as pixel colors.

Pixel Ratio
The proportion of pixel width to pixel height. In most cases, pixels are square,
giving a pixel ratio of 1 to 1. However, some formats use non-square pixels,
such as DVDs, which have a pixel ratio of 0.9 to 1. This can cause headaches
when working with non-square pixel formats on hardware that only displays
square pixels. All desktop computers use square pixels to display their
graphical user interface.

Plane
Plane refers to a two-dimensional (i.e., flat and level) surface. Imagine a plane
as a piece of glass that is infinitely large, but has no depth.

Plug-In
A plug-in is a program that works with and extends the functionality of
LightWave.

Point
A fundamental building element of an object in 3D space with an XYZ location.
Point coordinates are the minimum information from which the geometry of an
object can be calculated.

Point light
Light source emitting light in all directions (omni-directionally) from a single
point in space. It takes six shadow (one in each orthogonal direction)
calculations to render shadows generated by a point light, which means that

69

inserting multiple point lights in a scene might slow down rendering time
considerably. Point light emanates in all directions, think "light bulb".

Polygon
Geometric shape in one or many planes. Polygonal modeling consists of using
many faces to create the shape. Since polygons in most cases are faceted
simplifications of a much smoother shape, they are more or inaccurate, as
opposed to the more organic NURBS. The more the tessellation, the higher
and the closer the accuracy compared to the desired shape.
A closed 2D plane figure bounded by straight line edges. Polygons can be
connected to one another in 3D space to create mesh objects. In some
computer graphics applications, faces and polygons are synonymous, but
sometimes the term face refers specifically to a triangle. A polygon is
composed of one or more triangles which all lie in the same plane. For
example, a square polygon is made up of two triangular faces.

Poly-Line
A geometric entity composed of one or more connected segments that are
treated as single entity.

POV
Abbreviation for Point of View.
Primary colors
There are three primary colors of light: red, green and blue (RGB). Light colors
are additive, which means that if these three colors are combined equally, the
result is a white light. Black is thus absence of light.

Primitive
Basic geometric shape used in modeling. Some primitives consist of a
combination of different primitives. Cone, box, sphere, tube, torus, and disc
are common primitives.

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Procedural
An algorithm which generates data within the 3D graphic application. For
example, procedural 3D textures are patterns which do not require mapping
coordinates. Procedural animation generates motion, and may not involve
keyframes at all. Procedural modeling employs simple rules to generate
complex structures such as plants. Maya's Paint Effects is a superb example
of a tool for procedural modeling and animation.

Procedural Map
A map (often three-dimensional) generated mathematically instead of using an
image. The procedural map does not need texture coordinates. A map that is
not based on an image but generates the map using a set of user-customized
variables.

Procedural Textures
Mathematically generated textures (2D and 3D). Their advantage is that they
are largely independent of the projection type.

Progressive Scan
A video display mode which draws each scanline (row of pixels) sequentially,
and does not use alternating fields.

Projected Shadow
A shadow that falls from an object and projects on a surface.

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Projection Map
A mapping procedure that allows the user to apply the map to multiple objects
as if they were one.

Quad
A polygon with four sides, short for quadrilateral.

Quantize
This tool causes points to snap to a specific (X, Y, Z) coordinate. This tool is
generally used when a lot of precision is required.

Quaternion
Magically delivered full-grown to W. R. Hamilton in 1843, quaternions are
mathematical objects consisting of a scalar and a vector which together form a
four-dimensional vector space. Although having interesting uses in
mathematics, their main use in computer graphics resides in their capability of
easily representing 3D rotations. Although impossible to visualize, they suffer
from no singularities like Euler angles, and are also easy to smoothly
interpolate for keyframe animation (using a mathematical operation called
SLERP for Spherical LinEar intERPolation

Radiosity
A more physically correct approach (developed in 1984 by Siegel and Howell)
to simulate propagation of light in a virtual environment. It takes into account
the fact that light bounces off a surface and creates diffused lighting on the
surrounding objects. The scene is divided into a certain amount of triangles
that are used to represent the original scene (which speeds up the timeconsuming process), and then radiation interaction is calculated using these
triangles. As far as visual quality is concerned, the more crucial the part of the
scene the denser the triangles must be. This technique creates much more
realistically lit environments, however it takes much longer to render due to the
massive amount of calculations.

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A global illumination algorithm. A technique to calculate indirect light to

illuminate a scene. It uses radiative transfer theory.
Rendering which accurately simulates the propagation of light energy
throughout an environment. Radiosity works by calculating the effects of light
bouncing off of objects to illuminate other objects. It is a global illumination
algorithm, meaning it accounts for the ways in which light is transferred among
surfaces in the scene.

Rail Clone
This tool creates multiple copies of an object that are evenly spaced along one
or more user-defined curves.

Rail Extrude
This tool is used to extrude polygons along a specified line or combination of
lines. This allows the user to create a shape other than that created from a
normal, static extrude.

Rapid Prototyping
The process by which a computer model of a 3D object is turned into a real
object. Rapid prototyping methods vary but often involve laying down strata of
base material which is then bonded together using a substance like
cyanoacrylate (superglue).

Raster Image
A 2D image which is composed of a series of horizontal scanlines arranged in
vertical rows. Digital raster images are comprised of a grid matrix of pixels. All
bitmap images are raster-based. Converting a vector-based image to a pixelbased image is called rasterization.

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Rasterization
The process of, on a per pixel basis, determining what value to assign to the
pixels on the screen from a vector based image.

Ray-Traced Shadow
Shadow created by tracing the light rays from a light source. The ray-traced
shadows are more accurate than those created by shadow map, but takes
longer time to render and always have crisp edges

Ray Tracing
An advanced rendering technique capable of calculating reflections,
refractions and shadows.
Raytraced renderings take more time to generate, but have a photorealistic
quality. To keep rendering time to the minimum, keep the to the smallest value
necessary.
A specific rendering algorithmic approach technique which follows rays from
the eyepoint outward, rather than originating at the light sources. It produces
results similar to ray casting or scanline rendering, but facilitates more
advanced optical effects, such as accurate simulations of reflections and
refraction.
A type of global illumination rendering algorithm that excels at reflections and
refractions. Ray tracing realistically depicts scenes by calculating rays of light
entering the virtual camera lens. It works by drawing a ray from each pixel of
the rendered image backwards into the scene until it intersects with a surface.
If the surface is reflective or refractive, additional rays are generated, bouncing
off of the surface until they intersect with other surfaces, possibly generating
additional rays. This method is also used to generate ray traced shadows. If a
secondary ray bouncing off of a surface has a clear line of sight to a light in
the scene, then that light contributes to the color of the surface at the point of
intersection.

Ray Tracing Depth (Ray Recursion Limit)

Number of times the light bounces off a surface when ray tracing. Used to

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create reflections and/or refractions. For example, ray tracing two mirrors
facing each other with the ray tracing depth set to 3 will allow the image of the
reflected mirror to show the first mirror in it.

Reflection
Light that bounces off a surface. A mirror is highly reflective, whereas the
reflection of a matte rubber surface is insignificant.

Reflection map
Simulates reflections in a surface using the reflection map instead of actually
ray tracing the reflected image. This speeds up rendering time, but can also
be a give-away if the scene is animated.
A simpler method of rendering reflective surfaces than the computationally
expensive ray tracing technique. An image is mapped onto a reflective
surface. As the object moves, the reflection map maintains its orientation to
the world coordinate system, giving the illusion of a scene reflected in the
object.

Reflection-illumination model
Model used when creating two-dimensional images from three-dimensional
meshes. To produce more realistic and convincing images, the reflection
model imitates attributes of real-life objects.

Refraction
When light passes through a transparent material and into a denser or less
dense medium the light rays are refracted and change direction. Each material
has its own and depending on de density of the material the refraction is more
or less evident. Refractions are calculated similarly to reflections using ray
tracing.
Bending of light rays passing from one medium (e.g. air) into another (e.g.
glass). Can be simulating using refraction mapping (similar to reflection
mapping), or through ray tracing.

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Refraction index
A value describing the amount of refraction that takes place in a specific
transparent material. For vacuum the refraction index is 1.0000, for air 1.0003,
for glass approximately 1.5 and for water 1.3333.

Refraction map
An image to control the level of refraction across a surface where dark values
indicate a low refractive index and bright ones a high refractive index.

Render
To cause to become, to make, to process. To mathematically generate
geometries, algorithms, reflections, etc. Our work would be meaningless
without the ability to render. Creating a final image of a model that shows all of
the surface properties that have been applied to an object. This process
involves adding all colors; bump maps; shading; and other elements that add
realism. In a normal 3D program, the user can view the wireframe of the
created image. When an image is rendered, the wireframe is covered with the
specified colors and properties.

Rendering
In computer graphics, the process of producing 2D images from a 3D scene.
During rendering, the computer "draws" the 3D objects to the screen and/or to
a file, usually a bitmap. Realtime rendering occurs when viewing objects in
interactive viewports, or in games or simulations. Non-realtime production
rendering draws a much higher quality image, at the expense of speed. A
production render may take anywhere from a few seconds per frame to an
indefinite period of time... sometimes hours or even days for a single frame.

Render Pass
A division of a scene according to different aspects (such as highlight, mattes,
or shadows) for the purposes of applying specific rendering options. Passes

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can then be composited during post-production. The default pass is the beauty
pass, which includes all objects in the scene. Preset passes include matte,
shadow, and highlight passes. You can also define your own passes to include
any object you want to be affected by specific rendering properties. Render
passes are further divided into partitions.

Rendering pipeline
Description given to the process of creating the rendered images. Some
studios have a process by which all the images go through. Some render in
passes, one for the base, then the shadows, then the reflections, etc. This
process is the pipeline.

Resolution
The number of picture elements in an image.

Revolution
A modeling term defining a surface made by rotating a curve around the axis
of another curve.

RGB color model

A color model that mixes the three primary colors to produce colors. To create
yellow, red and green are mixed without any blue component. The higher the
value of the red, green and blue, the clearer the color. Lower RGB values give
darker colors, higher gives lighter.

Rigging
The process of making an object ready for animation. This does not have to
be just characters; it is the same for all objects. Rigging involves creation and
implementation of bones, hierarchies, clamps, weight maps and sliders.

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The process of setting up interactive controls for 3D characters or complex

mechanisms. Rigging is a technical process. It is sometimes called character
setup. A good character rig makes it easy for an animator to focus on creative
expression (acting).

Right-handed coordinate system

A coordinate system (frequently used in 3D-graphics applications) whose
positive Z-axis emerges from the screen towards the user, just like the one
used in mathematics, as opposed to the left-handed coordinate system.

Roll
The amount that a camera is tilted to the left or right. Also known as the bank
angle.

Rotoscoping
A technique in which video or film images are placed in the background of a
scene, one frame at a time. You can use these reference images to create
your own animation by tracing objects from the images or matching your
objects with the images' motion. You can zoom and pan the scene while
maintaining perfect registration with the imported background.

Row Interleaved
A format to create 3D video or images in which each row or line of video
alternates between the left eye and the right eye (from top to bottom).

Rule-Based Design
The definition of relationships between objects in the design. Another name
used to describe knowledge-based design.

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Scalar
A quantity, such as mass, length, or speed, that is completely specified by its
magnitude and has no direction, a one dimensional value.

Scanline Rendering
Rendering technique, or family of algorithms, that renders a scene one row of
pixels (or scanline) at a time. It works on a row-by-row basis rather than a
polygon-by-polygon or pixel-by-pixel basis.

Scanner
Device for reading images (from books, photos etc.) into the computer. This is
useful for creating realistic textures. With a 3D scanner it is even possible to
capture three-dimensional objects and convert them into models. A person
whose mother took part in a project created by Dr. Paul Routh and was given
ephemerol injections. Some can control minds and cause heads to expolode.

Script
In computer graphics, a script is a program that is interpreted and run by the
host application. For example, Maya uses scripting languages called MEL and
Python, while 3ds Max uses MAXScript. Scripting takes the tedium out of
computer graphics by automating tasks. It can also add functionality to the
host application, similar to a plugin. Scripts are human-readable, and are not
pre-compiled to binary code like most computer programs.

Scrub
The process of manually dragging the frame advance control slider on the
timeline to see or hear its effect on video/audio.

S-Drill
Refers to Solid Drill. Acts just as a drill would, using a 3D object as the drill bit.

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This tool can be used to take sections out of objects or perform other functions
that a drill might.

Seamless
A seamless texture can be tiled without visible transitions where the bitmap
begins and ends. This means that the upper part of the bitmap can be placed
next to the lower part of the bitmap (the same goes for the left/right part)
forming a pattern that is apparently coherent. Seamless textures have no
apparent seams.
SECAM
Squential Couleur Memoire. The television broadcast standard for France,
the former USSR, and various eastern European countries. Like PAL, SECAM
is based on a 50 Hz power system, but it uses a different encoding process
and displays 819 lines interlaced at 50 fields per second. SECAM is not
compatible with NTSC or PAL, but conversion between the standards is
possible.

Secondary Animation
Once the main movements of animation have been applied, this refers to the
detail animation step. Hoses bouncing with a robot walking, flab wiggling with
a heavyset character, these refer to secondary animation.

Sector
Convex volume used to speed up rendering time.

Self-shadow
Apparent shadow due to lack of incoming light

Self-Illumination (or Luminosity)

Allows non-homogene self-illumination of the surface. Some parts can be self-

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illuminated, some partially self-illuminated, and some not at all) based on the
pixel intensity of the self-illumination map.(normally black=left unchanged
white=self-illuminated

Session
A session is a single use of an application. A session begins when you first
start the application and ends when you exit.

Shaded Mode
Shaded mode generally refers to a viewport that has its Rendering Style
(Display Options panel or viewport title bar) set to something other than
wireframe. These modes show polygon surfaces with some level of shading.

Shader
A computer program used to determine the final surface properties of an
object or image. This often includes arbitrarily complex descriptions of light
absorption, diffusion, texture mapping, reflection, refraction, shadowing,
surface displacement and post-processing effects. In real-time shading
languages there are two different applications of shaders: vertex shaders and
pixel shaders. See material.

Shading
Simulating that an object is lit by a light source.

Shading Algorithm
A high-level rendering algorithm to represent how a surface responds to light.
A piece of computer code that is part of a material definition. For example, the
Blinn shading algorithm generically describes how highlights appear on
surfaces.

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Shadow
An area that is not or is only partially lit because of the interception of light by
an opaque object between the area and the source of radiation.

Shadow Map
Bitmap generated by the rendering engine during a pre-render pass of the lit
scene. Generally a shadow map is less precise than a raytraced shadow, but
takes less time to render. As opposed to a ray-traced shadow, a shadow map
can create shadows with smooth edges. Furthermore, the shadow map is
unable to show the color cast by a transparent object. The quality of the
shadows in the rendered image depends on the size of the shadow map. The
bigger the map the nicer the shadows. Too small shadow map might result in
aliased or stairstepped edges. For example, a 256x256 shadow map (65k)is
normally sufficient for resolutions of 320x200 and less. If an object is far away
from the light source, the shadow map will have to be increased in order to
maintain visual quality. If the final rendering is in high-resolution, the shadow
map also needs to be hi-res.

Skew
Modifying an object by tilting it

Smoothing
Technique that, when rendering or shading, smoothes out the edges between
segments making objects appear smoother than their geometry really are.
A rendering algorithm to give the illusion of smoothness on polygon mesh
surfaces. Without smoothing, all polygonal objects would have a faceted
appearance. Also known as edge smoothing or face smoothing. Smoothing
can be accomplished through the rotation of vertex normals.

Soft shadow
A shadow that does not have hard edges.

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Space
A set of elements or points satisfying specified geometric postulates: nonEuclidean space. The infinite extension of the three-dimensional region in
which all matter exists.

Specular
This property determines how shiny (and sometimes wet) an object appears. It
represents the highlight that the light creates when shining on an object.
The color of the highlight on a shiny object. The color of a specular highlight is
often determined more by the color of the light than by the objects color. See
diffuse and ambient color.

Specular component
Part of the reflection-illumination model. Specular surfaces are capable of
reflecting light like a mirror.

Specular map
Replaces the specular component of the reflection-illumination model, thus
only visible in an object's surface's highlights.

Specular reflection
The brightest area on a surface, reflecting surrounding light sources, creating
highlights.

Spherical Image Map

One of the many methods of applying a texture to a surface. This method
applies the texture to an object as it would apply the texture to a sphere. There

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are many other methods of texturing objects, such as Cubic and Planar image
mapping.

Spinning Llight Trick

Trick to create soft shadows with ray tracing. It involves parenting multiple
lights to a null and spinning the null.

Spline (Curves)
LightWave uses splines or curved paths between keys while moving items
about. When modeling, splines refer to open or closed curves.
In computer graphics, a spline is a line whose curvature is determined by
control vertices. Originally, a thin wood or metal strip used in construction.

Spline Cage
A spline cage is usually a three-dimensional object made up of connected
spline curves.

Spline Patching
Spline patching is the process of adding polygons to fill in areas outlined by
splines.

Spot
A small opaque circle placed in front of a light, usually to remove the a
specular hot spot off of an object.

Spotlight
A lightsource emanating light in one direction only, in the shape of a cone.

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SSS
Sub-Surface Scattering. The effect of light penetrating a surface and
illuminating the inner layers. Very important to consider when simulating
realistic skin and most other organic materials.Staircasing (or stairstepping)
A graphical flaw caused by insufficient resolution. When rendering an object its
contours might stand out too crisply from the background and the pixels might
be obviously "zig-zagged", or look like stairs. To prevent this, pixels can be
blended into their neighbors' colors by anti-aliasing.

Stencil
When using the drill tool, the stencil option adds the details of the drilling
polygon to the polygon being drilled. This creates new geometry on a shape.

Stereoscopic 3D
Two separate photographs taken from slightly different angles that, when
compiled, appear three-dimensional.

Stretch Tool
Allows the user to change the dimensioning of an object along a particular
axis. Basically, it stretches stuff.

Subdivide
This tool divides any selected polygons with three or four sides into smaller
polygons. This makes an object appear smoother, but also makes the model
more complex.

Subdivision Surfaces
Subdivision surfaces are a technique to create a smooth curved surface from
a coarse polygon mesh. Several different subdivision schemes have been

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developed since Catmull & Clark first introduced the idea back in 1978. The
most well known schemes are the triangle based Loop scheme and Catmull &
Clark's original scheme, which is based on quad polygons. Subdivision
surfaces moved out to the public in Pixars movies, Toy Story 2 and Geris
Game.
Algorithm that adds density to polygon meshes. It can be used as a modeling
tool, or invoked during rendering. Low density mesh objects are smoothed
through tessellation and smoothing of angles among adjacent faces.

SubPatch
Refers to a modeling mode wherein polygons become a cage that controls an
underlying mesh of subdivision surfaces.

Subtractive opacity
Sort of opacity that subtract the background color from the material's color of
the transparent object

Super pixel
They are created in a supersampling image. Groups of the superpixels are
filtered into the one single pixel that is displayed on the output display.

Supersampling
Generating images at a resolution n times n larger than the display resolution
and then filtering the co-called superpixels into the smaller resolution image,
creating smooth images with anti-aliasing.
An antialiasing algorithm that internally renders at high resolution, then
averages pixel values for a lower resolution output. Significantly reduces
aliasing on some textures at the expense of longer render times. Also known
as oversampling.

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Surface
The outer part of an object. The surface attributes can be changed using the
Surface panel. Such attributes as name, color, and many other features affect
the appearance of an object.

Surface of Revolution
A modeling technique to create rotationally symmetrical 3D objects by
revolving a spline around an axis. Commonly employed to create objects such
as bottles and lathed furniture pieces.

Taper
Modifying an object by progressively narrowing it along an axis.

Target
In aiming the camera, the target is the object that is selected for the camera to
point toward. The target is in the center of the scene.

TD
Short for Technical Director. Although some TDs dont wear shorts.

Technical Director
A job in a studio that concerns mainly making rigs. Also to help out the other
departments where ever possible. They are the problem solvers.

Tessellation
Increasing the detail level of a polygonal 3D model by increasing its number of
polygons, usually triangles . The more triangles, the smoother the shape and
subsequently the larger the model. The tessellation can be performed by

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dividing one triangle into two (or more) smaller ones. By doing this the new,
more faceted model can be modified without losing too much of its
smoothness.
The division of a surface into smaller polygons, yielding a higher level of detail.

Texel
Texture element. A pixel that is part of a texture map.

Texture
Normally texture describes the attributes of a surface, for example if its
coarse, smooth, wrinkled or rough, but it also used with the meaning of texture
map. There are textures made up from bitmaps (texture map) and textures
generated mathematically (procedural map). The specification of how the
surface of an object will look. Textures can be anything from simple, solid
colors to complex images representing the surface of the object. The simplest
example of a texture is placing a picture on a flat plane. The picture is the
texture being applied to the plane.

Texture coordinates
Coordinates used to describe how to map a texturemap onto an object. There
are different kinds of techniques to apply the texture: planar, box, cylindrical,
spherical and shrink map. Their names indicate how the texture is projected
onto the object the mapping coordinates are applied to. The shrink map
projection differs from the spherical projection in the way it only has one pole
where all seams meets. The modeler can manipulate the texture coordinates
to or mirror the texture. The procedural maps do not need texture coordinates.

Texture map
Map wrapped over the surface of an object. The texture map needs to be
spaced correctly in U and V direction over the object.

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A bitmap or procedural map to vary some property, usually diffuse color,

across a surface. The term texture map, in the strictest sense, means the
diffuse color map.

Texture Mapping
The process of projecting a (usually) two-dimensional image onto a threedimensional face such as a triangle or a quad, texture mapping is a relatively
cheap way of adding tremendous detail to a scene without resorting to
extremely detailed meshes that take an inordinate amount of memory and
time to render.
The process of assigning (mapping) an image (texture) to a 3d surface. This
allows a complicated colouring of the surface without requiring additional
polygons to represent minute details.

Tiling
Repeatedly placing the same texture next to itself on the same surface,
creating a pattern from one image. This is achieved by increasing the texture
coordinates on a polygon to a value greater than 1. Normally, the entire bitmap
is tiled from 0.0 to 1.0 in u- (=x) and v (=y). Tiling textures means placing them
next to one and other.
Timeline
The slider under the Layout viewport representing time in animation.

Tone mapping
Its a technique used to approximate the appearance of high dynamic range
images in media with a more limited dynamic range. Print-outs, CRT or LCD
monitors, and projectors all have a very limited dynamic range.
Essentially, tone mapping addresses the problem of strong contrast reduction
from the scene values (radiance) to the displayable range while preserving the
image details and color appearance important to appreciate the original scene
content.
Transform

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The mathematical reassignment of points to new locations. It's the abbreviated

form of transformation. The three transforms are position (aka translation),
rotation, and scale. These transforms control the location and orientation of
objects in 3D space.

Transformation
The act or an instance of transforming. The state of being transformed. A
marked change, as in appearance or character, usually, HOPEFULLY for the
better.

Truck
To move the camera in the viewing plane.

Tween
Tweening is the internal process of calculating the animation channel values of
all frames between keys.
Twist
Twisting a mesh by rotating its vertices non-uniformly along an axis.

U-direction
Represents a grid line in one direction (normally that of the original curve) of a
UV texture map.

Umbra
A dark area, especially the blackest part of a shadow from which all light is cut
off. The completely dark portion of the shadow cast by the earth, moon, or
other body during an eclipse.

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Unify
This command creates single-sided polygons according to the properties of
their surface normals. Basically, this tool transforms polygons that share points
into a single polygon.

Union
One of the options in the Boolean tool. This option makes an object that is a
combination of the two objects. A combination so formed, especially an
alliance or confederation of people, parties, or political entities for mutual
interest or benefit.

UV-grid
A grid system for identifying points on a surface. The U-direction and Vdirection are for the surface, what the X-axis and Y-axis are for the coordinate
system.

V (Vertex) Maps
V Maps is an abbreviation for vertex maps. V Maps provide additional
information associated with object points (vertices), like weight, UV and morph
maps.

V-direction
Represents a grid line in one direction (normally "up/down") on the surface of
an object.

Vector
Entity with both magnitude and direction. A three-dimensional vector is written
as:
V=(v1, v2, v3) where each component is a scalar.

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1. In computer graphics, a vector is a curve or line in 2D or 3D space. See

vector graphics. 2. In mathematics, a vector is a straight line with a length and
an orientation. A vector may be defined by any two points in space. It is also
commonly defined by a single point, an angle (two angles required for 3D
vectors), and a distance. 3. In Maya's MEL scripting language, vector refers to
a group of three numbers, such as the X, Y, and Z positions of a point.

Vector Graphics
Method for calculating or displaying data based on lines and curves rather
than pixels or voxels. 3D models, 2D illustration paths, and digital typefaces
are all examples of vector graphics. 3D models are constructed in vector
space and usually projected into pixel space for display.

Vertex
(pl. vertices) three-dimensional point that is the smallest component in a 3Dmesh.
Plural: vertices. A fancy word for point. Points are merely markers in space;
they have no dimension whatsoever no length, no area, no volume. Vertices
serve many functions in 3D graphics, from defining the contours of objects to
anchoring parts of a hierarchy together.

Vertex count
The number of vertices in a scene. Remember, the higher the mesh
complexity the longer the rendering time.

Vertex normal
Even though it is a single point in three dimensional space, its normal can be
calculated based on the normal of the face they are describing. The three
vertex normals of a single triangle without any neighboring triangles are set to
be the same as the polygon's normal. For triangles surrounded by other
triangles, the vertex normals are the average of the surrounding face normals.

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Lines pointing out from each vertex of a surface, important for lighting and
edge smoothing. The orientation of vertex normals determines how much light
the surrounding surface can receive. A vertex generally has several normals,
one for each face shared by the vertex. If all normals on a vertex are aligned,
the renderer draws gradients across the connected edges. If normals on a
vertex are pointing in different directions, the renderer does not smooth the
edges, resulting in a faceted appearance.

Vertex Shader
A real-time shader application. A graphics processing function used to add
special effects to objects in a 3D environment by performing mathematical
operations on the objects' vertex data. Vertex shaders are applied for each
vertex and run on a programmable vertex processor.

View Frustum
Representing the field of view of the camera, the view frustum is a pyramid
volume with the top sheared off. The top of the pyramid represents the
viewport of the camera (usually the screen), and is often called the near (or
hither) plane, while the bottom is called the far (or yon) plane.

View Frustum Culling

Removing faces that lie outside the observer's view. Only the faces that is
within the view frustum is kept for rendering - speeding up rendering time and
helping to maintain a high framerate.

Viewport
Window area displaying orthogonal or perspective projection in a 3D
application. The screen can either contain one big viewport or several smaller,
tiled viewports. By simultaneously using several viewports displaying a threedimensional object from different sides (e.g. top, front, left, perspective),
modeling in a virtual 3D environment is made possible.

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VIPER
Versatile Interactive Preview Render window that provides the user with an
interactive previewing system.

Volume
When selecting, a volume of an object is a 3D representation of the area to be
edited. When editing, all of the parts of objects contained within this 3D
selection can be edited without changing what lies outside of the selection.

Volumetric Fog
Fog that, opposed to ordinary fog, is restricted to fit within a containing
volume.

Volumetric Light
Light simulating illumination of particles floating in mid-air, thereby making the
light cone itself visible.

Vortex
A tool that rotates an object more in the center than in the outer edge. This
tool can be easily related to a tornado, where the wind in the center moves
faster than the wind in the outer part of the cone.

Voxel
Short for VOlume ELement, this term refers to a specific rendering technique
common in medical visualization as well as some interactive media. In
essence, a voxel is a three-dimensional pixel, that is, a cube, with a specific
color.
From volume element. A cubic unit of 3D volume defined at a size
appropriate to the required resolution, sometimes described as the 3D
equivalent of a pixel.

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Contraction of volume element. Compare to pixel. A voxel is a cubic section of

a volume, used for calculating certain volumetric effects such as fluid
dynamics.

Weld
This command takes the selected points and combines them into one point, a
single point that is specified by the last point that is selected.

WIP
Short for Work In Progress.

Wireframe
A way of visualizing geometry by drawing lines between its vertices and not
shading the surfaces within.

World coordinate system

The coordinate system, normally in three dimensions, used to describe the
location in space of a specific point called vertex.

X-Axis
Usually is the axis that is left and right.

Yaw
To turn about the vertical axis, also known as heading.

Y-Axis
Usually is the axis that is up and down.

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Y-up
Coordinate system with the Y-axis pointing upwards.

Z-Axis
Usually is the axis that is in and out.

Z-buffer
Also called depth buffer, the z-buffer is a two-dimensional matrix of 16- or 32bit integers with the same dimensions as the screen (or viewport). Whenever a
polygon is drawn to the screen, the rasterizer checks the corresponding zbuffer value for each screen coordinate and skips drawing the current pixel if
the z value is marked as being closer. This allows for some nice effects such
as overlapping 3D models, and completely solves the rendering-order
problem.
However, this comes at the price of slower performance and greater memory
usage, two factors that have become more or less moot with the proliferation
of modern 3D accelerators that tend to support z-buffers in hardware.
An area of memory holding the depth (Z) values of each surface in a 3D scene
represented at each pixel location at the rendered image.
Z-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. Z-buffering is also known
as depth buffering.
An automated method for managing depth information in a 3D scene.
Optimizes rendering by selecting which surfaces to render, and in what order.
The z-buffer ensures that occluded (hidden) surfaces are not rendered, saving
time.
Z-buffer or depth buffer information can be stored within certain bitmap file
formats such as .RLA and .EXR. The z channel records the distance of each
pixel to the camera. This information is useful in compositing. Simulated lens

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effects, such as distance blur from depth of field, can be added and adjusted
after the 3D images have been rendered.

Z-up
Coordinate system with the Z-axis pointing upwards.

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