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Three D Glossary - Animation

A

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

Aimpoint - The point of focus in both the 2D and the Perspective View mode.

Algorithm - An algorithm is a step-by-step method of solving a problem. Typically, this is a mathematical or computer problem.

Ambient Light - An artificial illumination level representing infinite diffuse reflections from all surfaces within a 3D scene, ensuring that even surfaces without direct illumination become visible to the user.

Animation - A medium that creates the illusion of movement through the projection of a series of still images or ‘frames’. The term is also used to refer to the techniques used in the production of an animated film - in 3D animation, primarily those controlling the motion of the objects and cameras within a scene.

Animation Channel – Refers to the different position, rotation, and scaling settings an item can have in Layout.

Animatic - A rough animation that is used by animators to give some idea about the timing of a sequence, used as a kind of animated storyboard.

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. Also known as "jaggies.”

Alpha Channel - When an image is created with 32-bit quality, 8 bits of that 32 are used for compositing. The alpha channel is what is used to make sure the composite is seamless so that it appears real.

Alpha Matte (Alpha Image) - This generally refers to an image where the brightness of each pixel is used to cause an effect on another image. These images are generally grayscale or black and white, but color images can also be used.

Ambient Light - Light that affects the entire scene and has no specific source. This light is the reason that no shadows in a scene are completely black. This is caused by the scattering of light from other objects. Ambient light fills in the shadows in the scene.

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.

Animate - To give motion to an object or a group of objects over a period of time.

Animation - A method of creating the illusion of life or movement in inanimate objects or drawings. Through animation the artist's drawing comes to life. The best-known works are cartoon comedies. The animator can freely distort both time and space and defy the forces of gravity through the process of animation. In an animation, a series of images (frames) create an illusion of movement when rapidly displayed in sequence. NTSC runs at 30 frames per second.

Animation Channel - The channel that holds the information for the different position, rotation, and scaling settings an item can have in Layout.

Anti-aliasing – The process of softening the unnaturally precise or stepped edges (sometimes known as ‘the jaggies’) created when a computer-generated object is placed against a contrasting background. Anti-aliasing usually involves the use of an imago- editing program to smooth the transition between dark and light colors. Whatever method you use, the purpose of doing this is to make the jagged lines less distinct by tricking the eye.

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 - The ratio of the width of an image to its height. Common aspect ratios for broadcast images include 4:3 and 16:9 (widescreen).

Axis – Refers to the XYZ coordinates used as the basis for positioning things in Lightwave’s 3D space. It is somewhat like the concept of up/down, left/right, and near/far.

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

Axis of Rotation - In 3-D space, Axis of Rotation is a line that an object rotates around.

B

Background Color - The color, which occupies all space that is not occupied by text, images, or any other objects. In text mode (DOS), this color is almost always black with text that contrasts to it (white, green, etc.). In Windows, Macintosh, and other operating systems, this color can be changed. Within word processing and most other applications, the background color is white with black text.

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

Bevel – A method of eliminating sharp edges from objects by extending an object’s faces.

Bitmap - An image format, which is made up of specifically colored pixels. A bitmapped image can also be referred to as a raster image. Both terms mean that the image is made up of many tiny dots. These dots are referred to as pixels. Bitmaps range from simple, black and white graphics to complex 24-bit color images that include all the colors of the spectrum.

Bone - What makes up 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 system developed by George Boole that expresses logical relationships between things. The results in a boolean operation can be either true or false. An object created by combining two objects using mathematical operators. The two objects may be subtracted from one other, merged, or intersected to form the new object.

Bounding Box - The smallest regular-shaped limiting box that encloses a 3D object, usually rectangular in shape that shows the largest possible area that an object may occupy.

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

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; it is an array of bumps.

Bump Map - A grayscale image used to give a surface the illusion of ridges or bumps. This image represents a sort of topographic map of an objects surface. Bump mapping is used to make a surface appear to be bumpy instead of the normal smooth surface that it would have by default. Bump maps are 2-Dimensional images and are generally done in grayscale, lighter colors representing higher altitudes (like peaks) and dark colors representing lower altitudes (like valleys).

C

Camera - In a 3D scene, the camera represents the viewer’s eye. As in real life, a camera records events. When the scene is rendered at final quality, it is the camera view that is used, rather than the one seen in the software’s workspace. . It can be moved, rotated, and animated like any other object. It is from this view that an animation or image is rendered. This enables the artist to move around the workspace without disturbing the camera view.

Center of the World - The absolute center of a 3-D space, represented by X, Y, and Z points (0,0,0).

Centerpoint - A point which represents the center of an object. This point is used in some programs for a point of reference for rotation and position.

Character Animation - A sub-area of animation that deals with the simulation of the varied movements of living creatures. Usually, before a character model can be animated, it must be set up with an underlying skeleton, constraints and controllers: this process is known as rigging.

Child - An object that is linked to another object as the child in a parent-child relationship. The motion of a child is influenced by that of the parent.

Clone - This tool makes 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.

CODEC - Short for "compressor/decompressor"; This is the term used to reference the way that software programs handle different movie files, such as QuickTime, AVI, etc. The CODEC can control image quality as well as how much spaces the movie file takes up.

Computer-Generated Imagery - An image or images created or manipulated with the aid of a computer. The term is often used to refer specifically to 3D computer animation, although it is really more widely applicable.

Compositing - The process of combining multiple images into a single image. This is often performed in films to make a live actor appear on a computer generated background, or vice versa. It can also be used following multi-pass rendering to combine the various render passes in different ways to control the look of a scene.

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.

Curve - A form in 3D that is created by interpolating between three or more points using a mathematical formula. There are many different methods of defining curves, two of which are Bezier curve and B-spline.

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

D

Depth of Field - A term used to describe the specific objects in a frame, which are in focus. Generally, in a 3-D program, all objects are in perfect focus. The depth of field is the range that encloses all of the objects in focus.

Diffuse - Light that is evenly reflected from an object's surface regardless of the angle from which it is viewed.

Dimension - Dimension is the expression of an objects length, width, and height.

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 - A recent advance on Bump Mapping. Like a Bump Map, a Displacement Map is a black-and-white image that a 3D software package projects over the surface of a model to generate surface detail. Unlike a bump map, however, a Displacement Map modifies the actual underlying geometry and is not merely a rendering effect.

Distant Light - A Distant light is a light which projects from an infinite distance away, creating parallel light rays.

Dither - A process that enables a system to create the illusion of displaying more colors than it can actually generate, dithering is accomplished by placing pixels of different colors to give the illusion of having more colors. This can be used when taking a 32-bit bitmap down to 8 bits.

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.

DXF- The most common 3D file format.

E

Edge - A line that joins two vertices. This line represents a single side of a polygon which, when combined with other polygons, makes up an object. Polygons that are adjacent (next to each other) share edges.

Envelope - A method of setting a particular value that usually changes over time through the use of a graphical input mode.

Extrude - A modeling technique in which a two-dimensional outline or profile is duplicated outwards to create a continuous three-dimensional surface. One example is to take a circle and it will extrude to make a cylinder. One of the most common uses of this tool is to create 3D text.

F

Face - A small triangular surface formed by the collection of 3 or more vertices. Most 3D programs use 3-sided faces, but some support 4-sided ones too. A collection of faces is referred to as a mesh. Each face also has a special entity tied to it called a normal. The normal defines which side of the face is considered to be the inside of an object, and which is the outside. Faces are clearly visible in wireframe and flat shading rendering modes.

Faceted - One of the options used with the Subdivide tools. This feature subdivides polygons leaving the newly created polygons in the same plane as the original.

Field of View - A term that refers to how much of a scene you can view at one time. The field of view is typically a pyramid shape. The measurement used to describe field of view is the angle that is created by the top of the pyramid.

Field Rendering - An option that causes the program to render two significant fields of information. This is opposed to rendering only one and makes moving objects appear to move more smoothly.

Flat shading - The flat shading algorithm calculates one color for each polygon in the model, based on the texture used and its position relative to light sources. The result gives a better indication of how the light source will affect the final render. The flat shading rendering is one of the fastest rendering algorithms.

Forward Kinematics - Often abbreviated to FK, Forward Kinematics is a character animation technique for controlling the motion of the bones in a chain – for example, a limb – in which rotations propagate from bone to bone towards the free end of the chain (in the case of a limb, towards the hand or foot).

Frame - A still two-dimensional image, one image out of many that define an animation. In computer animation, the term ‘frames per second’ (fps) is a measurement of the number of still frames displayed in one second to give the impression of a moving image. There are approximately 30 frames per second in NTSC video, 25 frames per second in PAL video, and 24 frames per second in film.

Frame Rate - The number of frames per second (fps) in an animation.

Freeze - When a MetaNURB object has been completed, the user should use the Freeze tool to create a polygonal shape out of the object.

Frequency - Measurement of the number of times certain textural characteristics repeat themselves within a fixed area.

G

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

Geometry - This refers to the positional layout of points and polygons for an object. In other words, this is a definition of each part of an object.

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.

Glow - A surface property that creates the illusion of light emanating from an object.

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.

H

Hierarchy - The relationship of the sub-objects within a model or a scene to one another. Sub-objects may exist as parents, children or independents. A parent object controls the motion of all child objects linked to it, although the motion of a child object does not affect that of the parent.

Hierarchical Linking - Connecting parts of a model so that they move in relation to each other. In a character model, the arms are linked to the body. The movement of the child object (the arms) depends, in part, on movement of the parent (the body).

Hierarchical Model - A model in which objects are linked in object trees. The movement of the child object depends on the movement of the parent.

Hub - A module in Lightwave that allows the Layout and Modeler modules to synchronize.

I

Image Map - An image that is applied to an object and is wrapped around the object's surface.

Image Mapping - A two-dimensional image applied to the surface of an object. Image mapping is useful for placing pictures or text onto objects, for example, a label on a model of a soda can.

In-betweening - The generation of intermediate transition positions between two keyframes. The term is drawn from traditional cel-animation, where a lead artist generates the beginning and end keyframes of a sequence (typically one second apart), breakdown artist does the breakdowns (typically four frames apart), and ‘in-betweens’ completes the rest.

Interpolation - The mathematical procedure by which a 3D software package calculates the in-between positions between two keyframes

Inverse Kinematics - Often abbreviated to IK, Inverse Kinematics is a character animation technique in which the end bone of a chain - for example, a limb – is assigned a goal object. When the goal object moves, the bone moves with it, dragging the rest of the chain behind it. The movement propagates from the free end of the chain towards the fixed point: the reverse of Forward Kinematics. For example, with IK, moving a character's hand will make the arm follow the hand in a natural manner.

Item – An item in Layout refers to an object, bone, light, or camera.

J

Jitter - This tool moves the selected points randomly within a specified range. This makes an object rough in appearance.

Jump - This tool causes the currently selected point to move to the current cursor position. The keyboard command for this command is the j key. If more than one point is selected, the last point selected will move to the cursor and the rest of the points will follow, but maintain the same space from each other in the move.

K

Keyframe - A frame that defines the beginning or ending of a motion or sequence. Keyframing allows the user to use a method of "tweening" between frames. Two keyframes are created, one for the original state of the object, and the second for the final state of the object. The 3-D program will interpret the changes between these frames and make appropriate changes in between them.

L

Lathing - Lathing creates a new object from a 2D profile by rotating it around an axis. Lathing is particularly useful for creating objects with rotational axes of symmetry, such as plates, glasses, vases or wheels.

Layer - A level of an image that can be edited independently of the rest of the image.

Lens Flare - A lens flare is what occurs when a camera points toward or near a bright light source. The effect is generally a star-shaped center with dots following in a line outward from it. The lens flare effect can be created as a light attribute to create the illusion of a bright light entering the camera's lens.

Light – A light in Lightwave is generally used just like a light in real life. A light in a 3D program is generally used like a light in real-life. Types of light supported within 3D packages include Point lights, which emit light in all directions from a single point; Spot lights, which emit light in a cone; Distant or Directional lights, which emit light rays in parallel, illuminating all surfaces within a scene; and Area lights, which emit light from two-dimensional surfaces.

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

Lightwave – The program that allows you to create scenes with what you created in Modeler and allows you to animate them.

Lip Synching - The process of matching a character’s facial movements to a spoken soundtrack during facial animation.

Loop - Any time that a sequence of images or sounds is repeated, it is considered to be a loop. In animation, a loop is when a certain portion of the animation is repeated over and over again.

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.

Low-Poly Modeling - The process of creating simplified models with low polygon counts, usually for use in videogames, where scenes must be rendered in real time, by software with a limited ability to handle complex models.

M

Magnet - This tool allows the user to move points in an object as if he or she were using a magnet. That is, the magnet tool pushes or pulls points depending on the user's specifications.

Map - Projecting an image so that it covers the surface of an object or images that affect the way an object looks.

Mapping - Applying an image onto the surface of an object.

Mesh - The surface geometry of a 3D model, made up of a series of linked geometry elements such as faces, edges, and vertices. The faces are arranged in such a way that they form the outside surface of that object.

Metaball modeling - A technique in which models are created using spheres (or, more rarely, other primitive objects) that attract and cling to each other according to their proximity to one another and their field of influence. Metaball modeling is particularly useful for creating organic objects.

Metaform - One of the options used with the Subdivide tools. This feature does not divide the polygons, rather it forms the edges of the polygons into curved, rounded shapes making the object seem less faceted and smoother.

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.

Model - Used as a verb, to model means to build a 3D object. Used as a noun, it means the 3D object created as the end product of the modeling process. A variety of different methods are used in 3D modeling, including polygonal, NURBS, Sub-D and metaball techniques.

Modeler – The program that allows you to create images

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Morph - To transform from one state to another. Morphing is commonly used in lip-synching, in order to transform the head model of a character between a variety of preset states (or ‘morph targets’), corresponding to common facial expressions, in order to create the illusion of speech.

Motion Blur - An artifact of real-world cinematography in which the camera’s target object is moving too quickly for the camera to record accurately, and therefore appears blurred. Many 3D software packages simulate motion blur as a rendering effect, in order to increase the realism of 3D images or animation.

Motion capture - Often abbreviated to mo-cap, motion capture is the process of recording the movements of a live actor, and converting them to a 3D data format which can then be applied to a virtual character.

Motion Path - A curved line or many linked lines drawn on screen, which represents the motion path of an object.

MPEG - (Moving Pictures Experts Group) A standard for compressing full-motion video, it enables far more video to be stored in a given amount of space than when uncompressed. Like JPEG, MPEG is "lossy" and MPEG compressed video is of lower quality than standard VHS video.

Multi-pass rendering - To render out the lighting or surface attributes of a scene as separate images, with a view to compositing them together later. Multi-pass rendering can be used simply to speed up the rendering process, or in order to develop the look of a scene by compositing the different passes together in various versions.

N

Noise - A mathematically defined pattern that uses variable degrees of randomness to generate its color pattern.

Non-planar - Refers generally to a polygon where all points do not reside in the same plane and can only occur with polygons using more than three points. Non-planar polygons can cause erratic rendering errors.

Normal - The imaginary line projecting out perpendicular to a polygonal face. They are represented as dashed lines on selected polygons in Modeler. 3D programs see polygons or faces of an object only from the surface normal side. A single sided polygon (like a piece of paper) with its normal facing away from the camera will be invisible to the camera from that viewpoint.

Null - An object that is not rendered in an image. These objects are used as points of reference when in a 3-D program. A null object can also be used for many other purposes, such as creating reference points for IK.

NURBS - Non-Uniform Rational B-Spline. Uses the basis of the b-spline, but has extra points added along the curve to create better precision in creating the curve. This process makes curves much more accurate and conforming to the user's specifications. Often used to model organic curved-surface objects.

O

Object - A generic term describing any item that can be inserted into and manipulated within a 3D scene. Models, lights, particle emitters and cameras are all objects.

Object Tree - A group of linked objects. An object tree can contain any number of parent and child objects. A model containing object trees is called a hierarchical model.

Opacity - A definition of how much light is allowed to pass through an object. When an object is 100% opaque, no light passes through it, when an object is 0% opaque, all light passes through it and it becomes invisible.

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.

Origin - The absolute center of the 3D universe. This point is defined by the XYZ coordinates 0,0,0.

Orthographic View - A view in which an object's distance from the viewer has no effect on the size at which it is drawn.

P

Pan - In a 3-D program, pan is a tool that allows the user to move the view with the mouse cursor, as if they were sliding the camera around.

Panel - In a 3-D 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.

Parent - An object that is linked to another object as the parent in a parent-child relationship. A parent object's coordinates become the center of the world for any of its child objects.

Particle System - An animation system consisting of a large number of very small points whose behavior is determined mathematically. A particle system typically consists of an emitter (which may be a point, surface or volume, and may emit particles directionally or in all directions) and a series of fields that determine the motion of those particles. Individual particles have a finite lifespan, and may possess attributes (such as color, radius, and opacity) that vary over the course of that lifespan. Objects and particles can usually emit other particles. A PS is particularly good for simulating and animating different phenomena, such as rain, fire, smoke, flocks of birds, crowd scenes or explosions. For example, instead of exploding an object into ten large pieces and creating an individual motion path for each piece, a particle system makes it simple to blow it up into hundreds of smaller pieces, without having to define an individual motion path for each piece. Every piece can then emit other particles(s) as smoke trails. Pixel – A pixel is the smallest unit of measurement in an image and is used to describe the image’s width and height. A single pixel in a Lightwave generated image can contain any one of the 16.7 million colors

Particles - 2-dimensional objects, typically used in large quantities that are used in natural movements.

Patch - A patch is a closed figure (area) made of 3 or 4 splines (3 or 4 connected points) that contain a patch entity. A surface can be a collection of patches.

Perspective View - In the perspective view, the farther an object is from the viewer; the smaller the object appears.

Perspective-Correct Texture Mapping - Texture maps that continually change to match the perspective of the viewer.

Phong Shading - A method of shading that applies the phong lighting model not to every polygon, but to every pixel of every polygon. Some phong shading algorithms can make 3D models look indistinguishable from the real thing. It's often bad at transparency and most phong-based algorithms can't produce shadows. This method of shading was developed by Bui-Tong Phong.

Pitch - The amount that the camera in the scene is tilted up or down.

Pixel - A pixel is the smallest element, a dot that makes up the image. A pixel can only show one color value, depending upon how much storage space is allocated for it. For example, a 24-bit image with the aspect ratio of 640*480 (640 pixels wide times 480 pixels high) consists of in total 307,200 pixels. Every pixel fills 24 bit in memory so the entire image needs 307,200 times 24 = 7,372,800 bits = 921,600 bytes of memory. Pixel is short for "picture element".

Plane - A two-dimensional surface in co-ordinate space. Essentially a flat sheet extending infinitely in all directions, a plane may be used to aid object manipulation, positioning and construction, and is not usually made visible in a final render.

Plug-in - A small piece of third-party software that is loaded into a 3D application in order to extend its functionality, for example, texture generation, and physics or fluid simulation. Plug-ins are available for object replacements, object displacements, surfaces/shaders, motions, final image filtering, and more.

Point - A one-dimensional point in coordinate space. Points can be linked up to form polygons, used as control vertices for NURBS curves, or employed as nulls to control lights or cameras, amongst other functions.

Polygon - A three or more sided 2D shape from which 3D environments are created, and which can then be represented on a 2D screen. Used to define the surface of a model.

Post Processing - The manipulation of a rendered image, either to improve the quality of that image, or to create effects that cannot easily be achieved directly within the 3D software itself.

POV - Point of view.

Preset - A pre-generated list of settings for a particular 3D software package.

Presets are usually used to control and customize properties such as rendering or lighting styles. Like plugins, they may either be commercial products, or freely downloadable from the Internet.

Preview - A timesaving method of checking the progress of a project by rendering it at a lower quality, resolution or frame rate than will be used for the final project.

Primitive - A simple three-dimensional form used as the basis for constructive solid geometry modeling techniques. Typical primitives include the plane, the cube, the sphere, the cone and the torus.

Procedural Texture - A texture map that is generated by a mathematical function, rather than a real-world bitmap image projected over the surface of an object.

Projection - The process by which a two-dimensional texture map is applied over the surface of a three-dimensional object, as if it were an image projected from a slide projector. There are several common projection types, including Planar, Cubic, Spherical and Cylindrical. Which one is most appropriate depends on the type of map being projected, and the shape of the object it is being projected upon.

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

Q

Quad view - A method of displaying 3D scenes adopted by many high-end software applications, in which a scene is shown simultaneously in Top, Side, Front and Perspective views.

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

R

Radiosity - A technique for rendering 3D scenes through calculating more accurately the ambient light by checking the reflections between surfaces. Radiosity simulates the way in which light bounces from surface to surface within a scene, and is more accurate, but also more processor-intensive, than raytracing.

Rail Clone - This tool creates many 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 setline or combination of lines. This allows the user to create a shape other than that created from a normal, static extrude.

Raster image - (see Bitmap)

Raytracing - A way of rendering a 3D image that follows the path of every ray of light. The light beam may be absorbed, reflected, or otherwise affected to some degree by every object it strikes. This produces the best image quality of all rendering algorithms.

Reflection Map - An environment map used to simulate real-world reflection effects on the surface of a 3D object. Reflection maps render more quickly than methods that generate true surface reflections, such as raytracing.

Reflectivity - The degree to which an object bounces light back from its surfaces.

Refraction - As a light wave passes from air through another medium such as water or thick glass, it seems to bend or turn to a certain degree. This phenomenon is known as refraction.

Rendering - 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 make an image appear realistic. In a normal 3-D program, you can see the wireframe of the image you are creating. When you render the image, the wireframe is covered with specified colors and properties.

Resolution - The size of the final image in pixels by measuring two numbers, which represent the number of pixels available across and down the screen. Higher resolution renders contain more detail, but take longer to complete.

Roll - The amount that a camera is tilted to the left or right.

Rotoscoping - A way of creating animation by tracing the movements of human actors from film or video. Previous to the advent of motion capture, this was the best way of getting smooth, human-like animation.

Rigging - The process of preparing a character model for animation, including setting up an underlying skeleton, complete with constraints, controllers and kinematic systems, and linking it to the mesh of the character model.

S

Scene – The 2D screen projection of your 3D environment, including the models themselves and the lights and camera that will be used when rendering them out.

Scene Editor – This button opens a panel that allows you to see all the elements in your scene. Objects may be displayed in a variety of formats from this panel.

Shading - The mathematical process of calculating how a model’s surfaces react to light.

Skeleton - An underlying network of bones used to define and control the motion of a model during character animation. Moving a bone causes the mesh of the model to move and deform.

Soft-Body Dynamics - The simulation of the behavior of soft bodies that deform on collision with other objects, such as cloth or fluid flows.

Solid Drill - Acts just as a drill would, using a 3-D object as the drill bit. This tool can be used to take sections out of objects or perform other functions that a drill could be used for.

Smooth - One of the different ways of subdividing an object. Smooth makes an object appear to have rounder edges. This results in a smoother looking object.

Specular - The "highlight" of any object with a shiny surface; light that reflects non-uniformly in specific directions dependent on the surface roughness.

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

Spline - An editable curve used to define the shape of a model. Also called curve or spline patch.

Spotlight - A light that sends a single cone of light off into a specific direction. The farther from the light an object is, the wider the effect of the spotlight is on that object.

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.

Stretch Tool - Allows the user to change the dimensioning of an object along a particular axis. Basically, this tool does exactly what its namesake says, it stretches an object.

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

Subdivision Surface - Also known as Sub-Ds, subdivision surfaces are surfaces created using a technique midway between polygon and NURBS modeling. They consist of an underlying polygonal base mesh, which is automatically subdivided by the software to create a smoothed final form. Sub-Ds combine much of the power of NURBS surfaces with the intuitive characteristics and ease of use of polygonal modeling tools.

Surface – Essentially, this is the skin of an object. A single object can have multiple surface names; each with its own independent attributes (e.g. color) and multiple objects can share the same surface name.

Symmetry - A modeling option in which any changes made to the model are duplicated across an axis of reflectional symmetry. This makes it possible to create complex symmetrical objects, such as a human or animal head, without having to work directly on more than one half of the model.

T

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.

Tessellation - The procedure of creating an object that is curved by approximating with lines. What tessellation looks like is taking a curved object and wrapping chicken wire or a net around it.

Texture - 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 Map - A special kind of bit-map, texture-maps are laid over or wrapped around polygons in 3D. Values from the texture can determine or affect any surface characteristic, including color, reflectivity, transparency or bumpiness.

Texture Mapping - Technique used to change the appearance of an object at the time of rendering. This technique does not actually create a texture for the object; rather it places an image on top of the object. Bump mapping is used to create true textures on an object.

Three-dimensional (3D) - Descriptive of a region of space that has width, height,

and depth.

Three-Point Lighting - A system of CG lighting derived from real-world cinematography, in which a scene is illuminated by three light sources: a Key light, which acts as the primary source of illumination for the scene; a Fill light, which illuminates shadow areas; and a Rim light, which illuminates the edges of objects and helps them stand out from the background.

Tiling - The process of duplicating a texture across the surface of an object. Tiling textures must be created so that the edge of one aligns perfectly with that of its neighbor, otherwise the result is a series of ugly seams.

Timeline - A fundamental element of the graphical user interface of most modern 3D software packages, which shows the timing of the keyframes in a sequence of animation. Playback of the animation may be controlled either by a series of VCR-like controls, or by clicking and dragging with the mouse to ‘scrub’ a slider to and fro along the timeline.

Transform - A group of commands used to change the surface of an object. This group includes surface, triple, subdivide, and more commands which are used to change the appearance of an object's surface transparency.

Transparency - Transparency is the measure of an object's ability to transmit light through its surfaces.

U

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

V

Vertex - The point at which two edges meet. For example, triangles have three vertices (plural), while squares have 4. Each vertex is a specific point in 3D space.

Viewport - The region of the interface of a 3D software package in which the scene is displayed to the artist.

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

Volumetrics - Volumetric lights are lights whose illumination can be observed throughout a volume of space, rather than simply where the light strikes a surface. In similar fashion, volumetric textures are textures applied throughout a volume of space, rather than to a surface.

W

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.

Walk Cycle - A short sequence of animation containing the keyframes necessary to make a bipedal character take two consecutive steps. The sequence may then be repeated over and over again to animate the character walking forward. Walk cycles may be modified in many subtle ways to suggest information about a character’s age, gender, emotional state or personality.

Weighting - The process of determining which bone in a skeleton affects which part of a model’s surface mesh. In many cases, this is achieved by painting weight maps onto the surface of the model that delineate a particular bone’s area of influence.

Wireframe - A mesh representation of a 3D object. Displays only the splines or polygons that make up the model.

World axes - See: Co-ordinate systems.

X

X-Axis - The axis that represents the left and right, or horizontal aspect of the modeling world. On the left of the axis are the negative values; on the right are the positive values.

Y

Y-Axis - The axis that represents the top and bottom, or vertical aspect of the modeling world. On the bottom of the axis are the negative values; on the top are the positive values.

Z

Z-Axis - The axis that represents the front and back, or depth aspect of the modeling world. In the back of the scene are the negative values; in the front of the scene are the positive values.

Z-depth - The distance a particular point or surface lies inside a scene. Z-depth

information is used to calculate where a light casts shadows, and also to calculate which surfaces are visible to the camera during rendering, and which are obscured

by nearer geometry.