the art of mayaart.ncc.edu/faculty/gorman_jason/courses/art138/... · Welcome to The Art of Maya - Personal Learning Edition. This virtual book will help guide you through the fundamental

the art of maya PERSONAL LEARNING EDITION

An Alias|Wavefront™ Education Learning Tool

|the |art |of |maya

Copyright © 2000, Alias|Wavefront, a division of Silicon Graphics Limited.

All rights reserved. No part of this book or CD may be disclosed to third parties, translated,copied, or duplicated in any form, in whole or in part, or by any means electronic, mechanical,photocopying, recording or otherwise without the express prior written permission ofAlias|Wavefront.

This document contains proprietary information of Alias|Wavefront, a division of SiliconGraphics Limited, and is protected by Federal Copyright law.

ISBN: 0-9685725-1-0

DisclaimerEvery reasonable effort has been made to obtain permissions for all articles and data used in thisbook, and to make it as complete and accurate as possible. This book should be considered “as is”and neither Alias|Wavefront nor its employees, officers or directors shall be responsible or incidentalfor consequential damages resulting from the use of this material or liable for technical or editorialomissions made herein.

International Standard Book Number (ISBN): 0-9685725-1-0

First printing: October 2000

2003 2002 2001 2000 7 6 5 4 3 2 1


Welcome to The Art of Maya - Personal Learning Edition. Thisvirtual book will help guide you through the fundamentalconcepts of 3D space, and animation in the context of Maya.This tool will help you understand the hows and whys of computer graphics. It takes many examples and samples fromour retail book, The Art of Maya. The Art of Maya - Personal Learning Edition will help you understand many ofthe theories you'll explore through the on-line tutorialsincluded with Maya Personal Learning Edition. For deeper discussions, additional images, and more advanced concepts, purchase The Art of Maya from our online store atwww.aliaswavefront.com.

Three-dimensional computer animation isvisible all around us. From new and excit-ing worlds created for movies to interac-

tive video games with rich textured environ-ments, the impact of 3D artwork is impossibleto ignore. Because the computer is involved,there has always been an emphasis on the technical aspects of creating thisimagery. However, the people using this soft-ware, more often than not, come from a cre-ative background in one of the visual arts.They recognize the benefits of learning thisnew media and are willing to acquire a deepknowledge of computers and 3D animationsoftware to master their craft. The quality ofthe artwork they produce is incredible and allof us have enjoyed watching 3D computer ani-mation’s popularity grow.

MayaTM is a 3D computer software packagethat pushes the boundaries of what can beaccomplished in the 3D animation field. It isan integrated package that mixes modeling,animating, texturing, dynamics, lighting, andrendering tools in one consistent UserInterface. Of course, the depth offered byMaya’s tool set can be daunting to new usersand even to 3D artists who have, over theyears, specialized in only one of the many disciplines involved in the animation process.With Maya, the possibilities seem almost endless.

This book is your guide to these possibili-ties. It is designed to provide a visual look atthe various concepts that go into the produc-tion of animations and interactive 3D media.While not all the possible tools and/or work-flows are explored, the book will give you anin-depth look at what Maya can do. You willlearn which tools will help you achieve yourgoals and why these tools work the way theydo. In some cases, Maya’s approach to calcu-lating an effect, such as lighting, is com-pared to a real-world approach with whichmany artists have previous experience. Bylearning how these two approaches are similarand how they differ, you will be able to trans-fer your skills to using Maya.

This book’s main focus is on understanding.You can choose to read this book before youstart working on the computer or you can getyour feet wet first, then come back to getthe big picture. Either way, this book is meantto be your companion as you explore the world ofMaya and its use as a creative tool. In time,you will find your focus shifts from Maya’stechnical issues to your artwork. Understanding how Maya works willfree your creativity and let you focus on pro-ducing impactful artwork and of course, cooleffects.

Animation is an art form created and cultivated over

the last century. While drawing, painting, sculpting,

and photography allow artists to represent shape

and form at a single point in time, animation lets

artists explore a world in motion.

Through animation, new worlds can be imagined.

This modern art form evokes emotion through the

movement of a sequence of drawings, paintings,

photographs or rendered images.

The introduction of 3D computer graphics over

the last couple of decades has had a big impact

on the world of animation. Digital characters and

sets can now be built and animated, then pre-

sented in different media formats such as film,

video, and interactive games. Characters and visual

effects can even be seamlessly integrated into

live-action footage.

Maya is a 3D animation system that lets artists

play the roles of director, actor, set designer,

and cinematographer.

3d computer graphics

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3D Computer Animation

The world of 3D computer graphics hasgrown from experimental short films tofull integration into the creative

process for many types of media. From flyinglogos to digital actors, the field of 3D com-puter graphics has evolved rapidly over thelast two decades. The use of 3D graphictools is now an important part of many tele-vision, film, and multimedia projects.

What makes 3D such a useful tool is theway it simulates real objects. The wayobjects appear in perspective, the way asurface bends and twists, or the way a lightilluminates a space – all of these complex 3Deffects can now be recreated on the com-puter. The resulting digital images can thenbe integrated into other media types usingfamiliar compositing and editing techniques.

Maya is a 3D animation system thataddresses the needs of a wide variety of dig-ital content creators. Maya’s tools and tech-niques have been developed with the artistin mind, while command-based scriptingoffers ways to build customized tools thatsuit more integrated production workflows.

BroadcastThere is a good chance that anyone involved inthe early years of 3D computer graphics has hadto animate a flying logo. This use of 3D offereda new and dynamic way of getting the messageacross – always important in the world of adver-tising. Since then, the use of 3D in broadcasthas evolved and more sophisticated artwork isbeing produced.

Flying logos are now integrated into morecomplete 3D environments where a product isadvertised or a corporate message introduced.Character animation is also used more to bringobjects to life and help sell the message.

Maya hashelped open thedoor to a morecomplex use of 3Din the broadcastworld. With inte-grated modeling,animation, charac-ters, visualeffects and ren-dering, a smaller video production house cannow easily add 3D into their existing 2D workflow.

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Feature FilmsThe last few years have seen a sharp rise in the use of 3Din feature films. While many films have integrated 3D intoexisting live action scenes, Pixar’s Toy Story® became thefirst feature-length animation that used 3D exclusively forcharacters and sets. Recently Sony Pictures Imageworks’Stuart Little® took this one step further and made a digitalmouse the star of a live-action movie. Digital creatures,characters and sets continue to show up in the movies and

even traditional filmmakers are starting toconsider 3D a standard part of the produc-tion process.

Feature films tend to use many comput-er programs to complete a project, includ-ing in-house software and off- the-shelfsoftware such as Maya. Maya is most oftenused for modeling, animation, characteranimation, and dynamics simulations suchas cloth. Maya’s open architecture makes

it easy for Computer Graphics (CG) supervisors to build cus-tom tools to help streamline production.

Interactive Video GamesOver the years, video games have devel-oped from black and white pixels to real-time virtual environments built with 3Dcharacters and sets. The graphics used inthese games have always conformed to the capabilities ofthe game console on which they are delivered. Tomorrow’snext-generation game systems use the same kind of comput-ing power as the workstations that you use today to runMaya. This is breaking down limitations of the past.

Game artwork is becoming more sophisticated with com-plex 3D models, texture maps, lighting, and even dynamics.Maya is an ideal tool for generating this kind of 3D artworkand includes tools to address the special needs required tobuild content for real time.

Visual EffectsWhile CG actors star in movies of their own, 3D computergraphics is changing how visual effects are used for bothfilm and television. Smaller productions can now afford tointegrate 3D graphics into their work while large film produc-tions can now achieve effects only dreamed of in the past.

Film sets can be partially built and then extended withdetailed 3D digital sets. Also, animated stunt people can bethrown off buildings in ways not recommended for real peo-ple. And, smoke, fire, and exploding objects can now be sim-ulated within the safety of a computer screen.

Maya’s tools, especially Maya’s Dynamics, are ideal forgenerating visual effects that can be fully integrated intolive-action shots. The best effects make it impossible to findthe line between reality and where computer graphics is used.

Visualization and WebDigital content creation tools are used in a number of fieldsincluding fine arts, architecture, design, education, and sci-entific research.

Some of these fields require 3D computer graphics to pro-duce highly realistic images for the evaluation of projects orprototypes. With advances in the web’s ability to presentgraphic and 3D information, visualization on the internet isemerging as an important tool for many companies.

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Technical Creativity

As an artist working in a new medium, you must firstunderstand the technical aspects of your new toolsbefore you can reach your full creative potential. Just

as a painter must learn how a particular paint mixes and drieson canvas, and a photographer must learn what film speedworks best with a particular lens, a 3D artist must learn the basics of setting keyframes, working with 3D geometry, andsetting up materials and lights for photorealistic rendering.

To fully master computer animation, you must have a bal-ance of artistic and technical skills. Not only must you learnhow to work with shape, form, motion, color, and texture,but also you must learn how the computer interprets all ofthese elements. While Maya will allow you to go far withoutunderstanding all the technical details, you will havegreater creative freedom with more knowledge.

Getting to Know Your ComputerIf you are sitting down at the computer for the first time,you may be intimidated by the many computer-based tasksyou must learn such as opening applications, moving andsaving files, and even how to work over a network. If youwork in a larger production house, you probably have tech-nical assistance on-site to help you get through this part ofthe learning process. In a smaller production house, youlikely have less assistance and must learn more on your own.Luckily, these skills come quickly with experience. The bestway to learn is to dive in and start working.

Getting Started with MayaThere are several steps to gettingstarted with Maya. This book isdesigned to give you a conceptualunderstanding of how Maya works,while the Learning Maya tutorialbook gives you project-based experi-ence. You can also use the referencemanuals and Web tutorials offeredat the Alias|Wavefront Web site.

While these academic tools areimportant, they can’t replace trueproduction hands-on experience.One good way to begin using thesoftware is to model, render, andanimate a real object -- an objectyou can study, document and accu-rately turn into a digital scene. Tryto build and animate your favoriteold toy, a household appliance oreven your own face.

By using a real object, you will beable to evaluate your successagainst the real object. By focusingon creating something you will beable to apply the knowledge youhave gained from this process.

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Transferring Traditional SkillsArtists with skills in traditional media will find the transition to 3D computer graphics easier oncethey get used to working on a computer. In fact, new 3Dartists should take the time to learn one or more of the following traditional art forms because they can helpenhance 3D skills:

Drawing and SketchingDrawing is a technique of representing the real world by means of lines andshapes. This skill requires the ability to observe and record the three-dimen-sional world. This skill can also be used to create storyboards and charactersketches, which are great tools for developing an idea before proceeding tocomputer graphics.

Cel AnimationCel animators create 2D art through motion. Cel animation includes traditionaltechniques such as squash and stretch, anticipation, overlapping action, andfollow through. Many of these 2D techniques translate very well into 3D envi-ronments.

PaintingPainters learn to work with color, light, shape, form, and composition. On thecomputer, these skills help create texturemaps, position lights, and compose scenes.

CinematographyKnowledge of traditional cinematography will help artists use real-world tech-niques when setting up CG lights and cameras. This skill is very important whenworking with 3D graphics that are integrated into live-action plates.

PhotographyStill photography requires an understanding of lighting and camera effectssuch as key lights, focal length, and depth of field. Photography also teachesgood composition techniques that are useful for framing scenes.

SculptureSculpturing with clay, stone, and metal requires an intimate understanding ofshape and form. Hands-on experience in shaping complex surfaces is a greatasset when working with digital surfaces in Maya.

ArchitectureArchitects often make good 3D artists because they are trained to think inplane, section, elevation, and perspective. Building models by hand is anotherskill they develop that makes it much easier to work in a digital environment.

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With 3D computer animation, artists work in a

digital world where space, color, texture, time,

shape, and form are tools for creating images

and sequences of images.

All of these physical realities must be translated

into a computer language based on numbers. In

fact, Maya scenes and images are really just data-

bases of numbers that are interpreted by Maya and

presented on the computer screen in a more visual

and artist-friendly manner.

While artists do not have to know how the num-

bers are interpreted by the computer, they do need

to understand some of the ways in which space,

color, and time are quantified and recorded.

Learning how the computer interprets digital infor-

mation such as 3D coordinates, frames per second,

or the RGB information stored in a bitmap image can

help artists understand how this information relates

to their own perception of time and space.

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Every day, you come into contact with three dimension-al objects and spaces. You have learned how to recog-nize and work with three dimensions in your daily

routine and have an intuitive feel for how it works. If youhave ever drawn a sketch, built a model or sculpted amodel, you also have a creative feel for how shape andform can be described in 3D.

Three-dimensional objects can be measured and quanti-fied. If you have ever measured the length, width, andheight of an object, you have analyzed its three dimen-sions. You can also determine an object’s position by measuring it in relation to another object or to a point inspace.

In Maya, you can explore three dimensional objects andrecreate them on screen as rendered images complete withlights and shadows.

XYZ Coordinate SpaceIn Maya, 3D space is measured using three axes that aredefined as the X-axis, the Y-axis, and the Z-axis. If youimagine looking into a movie screen, the width would bethe X-axis, the height would be the Y-axis, and the depthwould be the Z-axis. In Maya, these axes are presentedwith X and Z on the ground and Y as the height.

You can find any point in this 3D world by defining acoordinate for each of the axes. To help you visualizethese coordinates, a grid with axis indicators shows youtheir orientation.

3D Space

Two DimensionsWhen you measure the width and height of an object,you are analyzing two of its dimensions. The X and Yaxes can be used to find points on an object, suchas the center of the wheel or the position of theheadlight in this two-dimensional space.

Three DimensionsWhen you measure the length, width, and height ofan object, you must consider a third dimension asdefined by the Z-axis when defining points in space.

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TransformationsWhen an object is moved, rotat-ed, or scaled, the XYZ axes areused for reference. An object ismoved along, rotated around,or scaled along the chosen axisline. Values for these transfor-mations are stored for each ofthe three axes.

The Ground GridTo create a ground surface toreference your work in XYZ,Maya includes a grid that mapsout an area 24 x 24 units. TheX and Z axes are on the groundand form the lines of the grid.The Y-axis is the height.

OriginPoints in a 3D coordinate systemare measured against an originpoint. This point is assigned avalue of 0, 0, 0.

Axis indicatorTo help you visualize the threeaxes, each is given a correspon-ding RGB color.

X – red Y – green Z – blue

Y-up and Z-up WorldsBy default, Maya is Y-up where the Y-axis represents the height. Some3D packages, especially CAD applica-tions, might use Z as the height. Ifyou import a model from one ofthese packages, you have to eitherre-orient the model or set up Mayaas a Z-up world.

The axes indicatorspoint in the positivedirection for X, Y, and Z.

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Time

In the world of 3D animation, time is the fourth dimen-sion. An object will appear animated if it eithermoves, rotates, or changes shape from one

point in time to another. Therefore, learning howtime works is crucial to the animation process.

Both live action and animation use either film orvideo to capture motion. Both media formats use aseries of still images that appear animated whenplayed back as a sequence.

Film and video images are often referred to asFrames and most animation is measured using framesas the main unit of time. The relationship betweenthese frames and real time differs depending on whetheryou are working with video, film or other digital media.

Frames per SecondFrames can be played back at different speeds that are measured inframes per second (fps). This is known as the Frame rate and it is usedto set the timing of an animation. The frame rate is required to outputanimation to film or video, and to synchronize that animation withsound and live-action footage.

In Maya, you can set your Frame rate in the Preferences window. Bydefault, Maya’s frame rate is 24 fps. If you have a background in ani-mation, confirm your time units to ensure you set keys properly.

Because seconds are the base unit of time, it is possible to set keysat 24 fps, then change your frame rate to 30 fps. This will scale thetiming of your animation to match the timing as measured in seconds.

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How Objects Are Animated UsingKeyframesKeyframe animation is created by capturingvalues for attributes such as translation orrotation at key points in time. An animationcurve is then drawn between the keys thatdefines or interpolates where the objectattribute would be at all the in-betweenframes.

Animation curves can be viewed as a graphwhere time is mapped to one axis and the ani-mated attribute is mapped to the other. InMaya, virtually every attribute can be animat-ed in this manner. The way in which you setkeys and control the in-between motiondetermines the quality of an animation. Asscenes become more complex, you will learn tocreate control attributes that can drive themotion of different parts of your scene tohelp simplify the process of setting keys.

Mapping against TimeTwo keyframes are mappedagainst time, then an ani-mation curve interpolatesthe motion between thekeys. The shape of thecurve determines the quali-ty of the motion.

Pivot PointsYou animate objects in Maya based on asingle point called the pivot point. Thepivot for the whole scooter would lie onthe ground, while the pivot for a wheelwould be at its center. The position ofthe pivot sets the center of the axes forrotating or scaling objects in your scene.

Setting KeysWhen you know that your object orcharacter needs to be at a certainplace at a certain time, you set a key.With characters, you can create posesout of a number of keys set for differ-ent parts of the character.

In-BetweenThe position of objectsinbetween the two key-frames is determined bythe shape of the anima-tion curve.

Time in Frames

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Abitmap is a representation of an image, consisting of rows andcolumns of pixels, that is stored color information. Each pixel(picture element) contains a color value for a number of chan-

nels – red, green and blue. When you view these channels together,at a high enough resolution, all of the different colors form a com-plete image. These images can then be output to video, film, orprinted on paper.

Bitmap images play a number of roles in an animation system suchas Maya. When Maya renders a scene, the geometry, lights, andmaterials are calculated from the camera’s point of view and abitmap image or a series of images results. Further manipulation ofthe image in two dimensions is then possible using compositing orpaint packages. Bitmap images are also used as texture maps tohelp add color and detail to the surfaces in scenes.

Bitmap Space

A bitmap image can be made up ofmany channels, each carryinginformation about the image. Fora typical image, the channelswould be red, green, blue, andalpha (RGBA). The alpha can beused to mask the other channels.

PixelsUp close, you canclearly see the gridof pixels that makeup the bitmapimage.

Full ResolutionAs pixels are presented at ahigher resolution, the grid is no longer visible and youget a clearer view of thefinal image.

Bitmap ChannelsEach pixel is made up of atleast three color values –red, green, and blue. These channels combine to create the visible color.

Bitmap SourcesBitmap images are common incomputer graphics and can becreated and manipulated inpaint, compositing, and 3Drendering packages.

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Image and DisplayResolutionMaya uses the term Image resolutionto refer to the total pixel size of thebitmap image. Display resolutionrefers to how many pixels you willfind in 1 inch on the screen. This res-olution is measured in pixels per inch(ppi) or dots per inch (dpi). Monitorshave a display resolution of about 72 dpi, although your graphics cardmay offer several settings which willalter this value.

As an animator, you will focus onproducing images with a particularImage resolution such as 640 x 480pixels for video or one of a variety ofresolutions for film. The defaultDisplay resolution for these images is72 dpi. If you are taking an image toprint, you will need to consider aDisplay resolution of around 300 dpi.This value may be higher or lowerdepending on your printing needs.Below, you can see how differentresolutions look when printed. Youcan see how the 300 dpi image pro-vides a higher quality image on theprinted page.

Other ChannelsIn a typical bitmap, the first three channelscontain color information. You can also createother channels that offer useful informationabout the image. Maya is able to renderimages with mask and depth channels for usein compositing packages. These channels canbe used when you want to layer several imagestogether seamlessly, including live-actionplates created outside Maya.

Mask ChannelA mask (or alpha) channel,defines where an image needsto be solid or transparent. Thischannel can be used to layerimages for compositing or totexture map attributes such astransparency or bump.

Depth ChannelA depth channel can provideactual 3D information aboutan image. Images are veryuseful in a compositing pack-age where you can combinelayers or add effects such asfog or depth of field.

2” x 2” @ 72 dpi (144 x 144 pixels)

2” x 2” @ 150 dpi (300 x 300 pixels)

2” x 2” @ 300 dpi (600 x 600 pixels)

Before exploring modeling and animation concepts, it

is a good idea to become familiar with the way

Maya’s user interface works. The user interface is

where 3D artists display and organize scenes, save

and open files, and transform and animate objects.

While developing these skills 3D artists learn just

how they can make Maya do what they want it to.

Maya has a very clean user interface where many

of the elements share generic editor windows. At

first, this may make it difficult to distinguish differ-

ent parts of a scene, but with experience 3D artists

learn the power of this paradigm. The generic way in

which Maya presents information makes it very easy

to transfer skills from one area of Maya to another.

This lets 3D artists focus on learning Maya’s underly-

ing concepts instead of always re-learning how the

user interface works.

Maya’s Dependency Graph concept links virtually

all objects in a scene to each other. As 3D artists

learn more, they discover this underlying structure

plays a key role in how they work and animate in Maya.

exploring maya

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The Workspace

Creating an animation in Maya involves the manipulation ofmany graphic elements such as curves, surfaces, colors, andtextures. Information about these elements is stored in Maya

as numeric values that can be viewed in a number of different ways.In Maya’s workspace, you can choose how you want to view a sceneand access different tools to alter its 3D information. Maya offersseveral ways of accessing and altering your scene, giving you theflexibility to build workflows that best suit the way you work.

The HotboxThe Hotbox gives you accessto all of Maya’s menuitems and tools right atyour cursor position. Whenyou press and hold downthe Space bar on yourkeyboard, after a shortdelay the Hotbox appears.The Hotbox is fully customiz-able and lets you focus on thetools you feel are most importantto your workflow. The HotboxControls let you turn off the mainmenus and the panel menus in theworkspace. When the menus andpanels are off, you can focusentirely on using the Hotbox.

User InterfaceElementsWhen you first launchMaya, the workspace ispresented to you with anumber of user interface(UI) elements. Each isdesigned to help youwork with your models,access tools, and editobject attributes.Initially, you shouldlearn the locations ofthe UI elements so youcan easily find themwhile you work.

Many UI panels can be set up asfloating windows in case you needthem just temporarily. Menus canalso be broken off from the MainMenu bar in case you need to focuson the menu’s contents.

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Time SliderThe Time Slider shows youthe time range as definedby the range slider, thecurrent time and the keyson selected objects orcharacters. You can alsouse it to “scrub” throughan animation.

Quick Layout ButtonsThe Quick Layout Buttonsprovide predifined conigurations of the Mayaworkspace. The RightMouse Button over thesebuttons will also giveaccess to more options.

Help LineThe Help Line gives a short description of toolsand menu items as you scroll over them in theUI. This bar also prompts you with the stepsrequired to complete a certain tool workflow.

Command LineThis bar has an area to the left forinputting simple MEL commands and an areato the right for feedback. You will usethese areas if you choose to become famil-iar with Maya’s MEL scripting language.

Channel BoxThe Channel Box lets you edit andkey values for selected objects.

PanelsThe workspace can bedivided into multiple panels that offer differentways of creating and evaluating your scenes.

Range SliderThis bar lets you set up the start andend time of the scene’s animation anda playback range if you want to focuson a smaller portion of the timeline.

PlaybackThe Playback controls let you movearound time and preview your animationsas defined by the Time Slider range.

CharactersThe Character Menu lets you defineone or more characters, then pre-pare them for being animated.

Menu SetsWhile Maya’s first sixmenus are always available, the remainingmenus change dependingon which Menu Set youchoose. This helps focusyour work on related tools.

MenusMenus contain tools and actions for creat-ing and editing objects and setting upscenes. There is a main menu at the top ofthe Maya window and individual menus forthe panels and option windows.

Status BarThe Status Bar contains shortcuts for anumber of menu items as well as tools forsetting up object selection and snapping.A Quick Selection field is also availablethat can be set up for numeric input.

ShelfThe Shelf is available for you to set upcustomized tool sets that can be quicklyaccessed with a single click. You can setup shelves to support different work-flows. Press Shift+Ctrl+Alt when select-ing a menu item to add it to the Shelf.

LayersMaya has two types of layers. DisplayLayers are used to manage a scene,while Render Layers are used to setup render passes for compositing. Ineach case, there is a default layerwhere objects are initially placedupon creation.

QWERTY ToolsThe “qwerty” hotkeys canbe used to Select (q), Move(w), Rotate (e), Scale (r),and Show Manipulators (t)as well as access the lasttool used (y) in the scene.

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Viewing 3D Scenes

When building a scene in Maya, you work in three-dimensional space.Orthographic and perspective view cameras offer ways of looking atthe objects in your scene as you work. There are also different

display options that change the way objects in your scene are shaded.

Default ViewsIn Maya, the default views are set as Perspective, Top, Front, and Side. ThePerspective view is a representation of your object in 3D space allowing you tomove along the X, Y, and Z axis. The Top, Front, and Side views are referred toas orthographic views and allow you to move in two dimensions at a time.

Default Top View Default Perspective View New Back View

Default Front View Default Side View New Perspective View

TumblePress the Alt key plus theleft mouse button to rotatethe camera around a 3D perspective view.

DollyPress the Alt key plus the left+ middle mouse button todolly in and out of your scene.

TrackPress the Alt key plus themiddle mouse button to panfrom left to right, and up,and down.

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Bounding BoxBounding Box displaysobjects as boxes. This isuseful when working withcomplex scenes.

Wireframe Wireframe shading is thedefault shading qualityin Maya.

Flat ShadeFlat shade displaysobjects with lower reso-lution faceted display.

Smooth ShadeSmooth Shade displaysobjects as smooth sur-faces with surface colorand shading properties.

Hardware TexturingHardware Texturing dis-plays smooth-shaded sur-faces with textures.

Hardware Lighting Hardware Lighting dis-plays smooth-shaded sur-faces with textures and lighting.

PointsPoints shading displaysobjects as a group ofpoints that representthe shape of the object.

Smooth andFlat Shading When choosing toview your objectsas Smooth Shadedor Flat Shaded,Maya offers theoption to shadeonly selecteditems in a view orall items in a view.

ShadingMaya’s Shading menu offers sev-eral options for displayingobjects in a scene. Shading canbe different for each view panel,allowing geometry to be shown atdifferent levels of complexity.

The more detailed a scenebecomes, the greater the needto simplify the objects in it.Although Maya is very good atprocessing complex levels ofgeometry, it is a good idea toview your objects in a less com-plex shading mode until you areready to render or make adjust-ments to those objects.

There are several shading dis-play options to choose from. Thedefault shading in Maya isWireframe. Other display optionsinclude: Bounding Box, Points,Flat Shade, Smooth Shade,Hardware Lighting, Wireframe onShaded, and X-Ray.

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Objects and Components

You can transform objects in Maya by selecting objects and theircomponents. Selection masks allow you the flexibility to select onlythe items you want in a scene. These masks are grouped into three

categories: Hierarchy, Object type, and Component type selections.

SurfacesSelecting by Surfacesallows you to select the sur-face geometry of an object.

Skeleton JointsSkeleton joints are usedto help control characters.

DeformationsDeformers such as clus-ter flexors and lattices modi-fy the shape of an object.

CurvesTurning off the Curveselection means you can not select the curves in the scene.

DynamicsDynamic objects such asparticles can be separatelyselected by toggling theDynamics button on.

RenderingScene objects such aslights, cameras, and textures are rendering object types.

HandlesIK handles are appliedto joint chains for animationcontrol.

Object TypesScene objects are items suchas Cameras, Curves,Surfaces, Dynamics, Joints,Handles, and Deformers.Objects created in Maya aremade up of two parts: aTransform node and a Shapenode. The Transform nodecontains information aboutan object’s position and ori-entation in space. The Shapenode defines what theobject looks like.

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HullsHulls are guidesthat connect CVs. Theycan be used to selectand transform rows ofCVs at once.

Param PointsParam points arepoints that lie directlyon a curve or surface.

Pivot PointsPivot pointsdetermine the locationaround which transforma-tions occur.

LinesLines such as isoparms and trim edgesdefine the shape of anobject.

FacesFaces are patchescreated by inter-secting lines.

PointsPoints such as CVs andpolygonal vertices areused to modify the shapeof an object.

Component TypesIn order to change the shape of an object in Maya,you need to modify component-type information.

There are a variety of component types such aspoints,isoparms, faces, hulls, pivot points and han-dles. These components can be used to interactivelymodify and reshape the appearance of an object.

�Selection Masks

Selection masks allow you to select thespecific items you want to work on. Thereare three main groups of selection masks:Hierarchy, Object, and Component.

Hierarchy mode allows you to selectnodes at different levels. In this mode youcan select the Root, Leaf, and Templatenodes.

Object mode allows you to select sceneelements at the Transform node level.These include objects such as surfaces,curves, and joints.

Component-type selections are selec-tions made to objects at the Shape nodelevel, such as isoparms and CVs.

hierarchy

Selecting by Hierarchy allows you to select objects at either the Root, Leaf or Template node level.

Unlike Object and Component selection masks, you are not able to turn on more than one mask at a time.

Object

Object selection masks allow you to make selections based on the object types you specify. Left-clicking

on the arrow to the left of the pick masks displays a menu allowing you to turn all objects on or off.

Component

Component selection masks offer a variety of pick masks to choose from. Right-clicking on a mask

displays more selection options.

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Dependency Graph

Everything in Maya is represented by a node with attributes thatcan be connected to other node attributes. This node-basedarchitecture allows connections to be made between virtually

everything in Maya. Node attributes determine such things as theshape, position, construction history and shading of an object. Withthis architecture, you can create inter-object dependencies, shadinggroup dependencies, and make your own node connections.

Nodes with Attributes that are connectedThe Dependency Graph is a collection of nodes which are connectedtogether. These connections allow information to move from one nodeto another and can be viewed in a diagrammatic fashion through theHypergraph and Hypershade windows.

Right Mouse ButtonClicking the right mouse buttonover a selected object will giveyou access to an object’s inputand output connections.

Animation CurveWhen an animation is produced in Maya, node dependenciesare created between the animation curves and the objectbeing animated.

Node DependenciesIn the diagram below you can see the nodes thatare dependent on each other to make up a chesspiece. Each node plays a part in creating thefinal rendered object. Here you see that theMaterial node is dependent on the Shape node torender the material, the Shape node is depend-ent on the revolve node for the chess piece sur-face, and the Revolve node is dependent on theCurve node to make the revolve.

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Attribute EditorIn the Attribute Editor,you can adust the attrib-utes on the input andoutput connections of aselected node.

Channel BoxIn the Channel Box, you can editany keyable attributes on theselected node.

HypergraphIn the Hypergraph window,you can see the input andoutput connections of aselected node.

Viewing DependenciesDependencies are relationships createdbetween nodes that are connected. There aremany ways to view and edit dependencies inMaya including the Hypergraph, AttributeEditor, and Channel Box.

By selecting a node and clicking the Up andDownstream Connections button in theHypergraph window, you can view nodedependencies on a selected node. This windowvisually displays the connection betweennodes with arrows showing the direction oftheir dependency to one another.

The Attribute Editor is made up of severaltabs allowing you to view related nodes of adependency group. In the Attribute editor,you can edit the attributes that affect thesenodes.

In the Channel Box, the selected node isshown with a listing of any keyable attributesthat belong to it. Depending on the nodeselected, it will also show input, output, orshape nodes. If you select more than onenode with the same keyable attributes, youcan modify them at the same time using thechannel box.

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Transformations

Move ToolThe Move Tool has a handlefor each X, Y, and Z axisand a center handle to moverelative to the view.

Rotate ToolThe Rotate Tool has a ringfor the X, Y, and Z axes. Onering moves relative to theview, and a virtual sphererotates in all directions.

Scale ToolWith the Scale Tool, you canscale non-proportionally inX, Y, or Z. You can also scaleproportionally by selectingthe center handle.

Transformations are changes made to an object’s position,orientation, and scale in space. The Transform node holdsall of this information and the Transform manipulators such

as the Move, Scale and Rotate Tools are used to transform anobject along the X, Y, and Z axes.

ManipulatorsManipulators are used to move, scale, and rotate objects inorthographic and 3D space. Each of the manipulators uses red,green, and blue color handles matching the colors of the X, Y, Zlocator at the bottom left corner of the view, making it easierto distinguish the direction of the transformation. These han-dles are designed to constrain the transformation to one, two, orthree axes at a time, allowing for complete control.

Move/Rotate/Scale ToolThis Tool incorporates the Move, Rotate,and Scale manipulators into one tool.Select Modify > Transformation Tools >Move/Rotate/Scale Tool to use this Tool.

Transformation ToolsTo work quickly and efficiently inMaya, the QWERTY Hotkeys offera fast way to access the trans-formation tools. These tools arelocated at the top left corner ofthe Maya workspace. Select,Move, Rotate, Scale, and theShow Manipulators Tools plus anextra space for the last tool youused, are all a part of the QWER-TY tool set.

q w e r t yUse the QWERTY shortcut keys on your key-board to select and transform the objectsin your scene.

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Setting Pivot Points for TransformationsObjects are transformed around their pivot point location. This is important to beaware of because the position of your pivot point affects the outcome of yourtransformation. To change the location of your pivot point, select a TransformManipulator and press the Insert key on the keyboard. Move your pivot point to thedesired location and press the Insert key again to set the pivot point.

Reset TransformationsOnce you have manipulated anobject, you may not be satisfiedwith its new transformation. Toreset your object to its originalposition, selectModify > Reset Transformations.

Freeze TransformationsSelect Modify > FreezeTransformations to keep yourcurrent position as thedefault position. This meansthat your modified positionwill have values of 0 for Moveand Rotate in the X, Y, and Z axes and a value of 1 for Scale.

Pivot point is in the wrong location.

Object is rotating around a properly positioned pivot point.

2D TransformationsWhen transforming an objectusing the Move Tool in theTop, Front and Side views, youare constrained to move onlyin two dimensions.

When using the Rotate andScale tools in an orthographicview, you can transform anobject in both two and threedimensions.

When 3D artists animate, they paint with motion

instead of color. As an object moves, rotates,

or changes shape over time, it is being animated.

This motion can be at a constant speed or it can

accelerate or decelerate. At times, this motion will

attempt to mimic real-world events such as an object

falling off a table, while at other times,it will take

the form of an actor telling an audience a story.

Models that are animated must be set up with

mechanical properties that define how they work.

To have a door open and close or a drawer slide in

and out, 3D artists must understand the mechanics

of their models so they can animate them.

There are a number of tools for creating motion

in Maya. In some cases 3D artists will animate all the

parts of an object separately. In others cases, they

use higher level controls to help streamline their

workflow. Situations can even be set up where the

animation of one object controls that of another.

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Animation Techniques

When you animate, you bring to life otherwise static and motion-less objects. You take aspects of the object such as its position,size, shape, and color and change these over time. If these

changes are set up properly, you create motion that instills characterand life in the object.

In Maya, there are a number of ways to animate an object. Using abouncing ball as a common example, it is possible to explore the differentanimation techniques available in Maya. In a real project, you will mostoften combine several of these techniques to achieve the best results.

Setting KeysSetting keys, or keyframing, is the most fundamental technique for ani-mating in 3D on a computer. This technique involves recording attribute val-ues as keys for one or more objects at particular points in time. As you setmultiple keys, you can play back the scene to see your object animated.

Setting keys gives you a great deal of control over timing. When youanimate using keys, you generate animation curves that plot the keyvalues against time. These curves are great tools for analyzing and edit-ing the motion of an object. Other animation techniques are usually com-bined with some keyframing. Most animation you do in Maya will involvesome form of setting keys.

Animation CurvesBy setting keys, you map the attribute’svalue to time. The keyframes are thenconnected by an animation curve thathelps define the attribute in between thekeys. Maya’s Graph Editor shows you thespeed of the motion and lets you reshapethe curve.

Keying AttributesBy setting keys on attributes at differenttimes, you define the motion of anobject. For example, Translate X is keyedat the beginning and end of the bounce.Translate Y is keyed with an up and downmotion that is fast near the ground andslow near the peak of the bounce.

Path Pivot

Translate Pivot

Scale Pivot

Rotate Pivot

Hierarchical AnimationYou set many of your keys on theTransform nodes of your object. Bygrouping an object to itself, you canset up different nodes with their ownpivot points and orientation, then keythem on their own.

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Path AnimationPath animation involves attaching the objectto a curve where points on the path are usedto determine where the object will be at par-ticular points in time. It is easy to under-stand the way an object moves around in 3Dspace through a path, since its curve clearlydepicts where the object is going.

A curve is used to represent the path of the bouncing ball. Thismethod lets you describethe path of the bounceby shaping the curve, buttiming the bouncerequires the setting ofseveral motion path keysto lock down the motion.

Path Pivot

Set Driven KeySet Driven Key allows you to control, or "drive",the value of one attribute with another attrib-ute. The relationship between the two attributesis defined by an animation curve. The drivingattribute can be used to drive multiple attrib-utes. For example, the rotation of an elbow jointcould drive a bulging bicep muscle and the wrin-kling of a sleeve.

Custom attributes can be added to a controlnode, then connected to other attributes inthe scene using Set Driven Key. This createscentralized controls.

Drivers Set Driven Key lets you use oneattribute to drive other attrib-utes. Here the Translate X ofthe ball drives the Translate Yand roll of the ball. As the ballmoves forward, the bouncingaction takes place.

ExpressionsAnother way of animating object attributes isthrough expressions. Expressions can be mathe-matical equations, conditional statements, orMEL commands that define the value of a givenattribute. Expressions are evaluated on everyframe. You can animate using an expressionwhen you have a mathematical relationship that you want to achieve. In the case below,the absolute value of a sine wave creates thebounce of the ball.

Dynamic SimulationTo animate a ball that is bouncing off a series of objects or against anon-flat terrain, a dynamics simulation is required for the most realisticresults. The ball can be turned into a rigid-body that is propelled for-ward using dynamic attributes. Forces such asgravity or wind can then be applied to theball to bring it to the ground.

Objects in the scene can also beturned into rigid-bodies so the ball willcollide with them. If they are passive,they will not be affected by the colli-sion, and if they are active rigid-bodies,they will move as the ball hits them. In theend, the simulation can be baked to turn themotion into keys.

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Setting Keys

For an object to be animated, it must change over time. For example, acar might move forward or a light might blink on and off. To animatethese changes in Maya, you need to set keys for the car’s Translate X

attribute or for the light’s intensity. Keys are used to mark attribute valuesat specific times. Then, animation curves are used to determine the value in-between the keys.

As a 3D artist, setting keys is one of your most important techniques. Thisanimation technique can be easily applied to your objects and the results canbe easily edited. Once you are familiar with this technique, you will soon findthat you spend less time setting keys and more time editing the motion.

Keying AttributesWhen you set keys, you key values for one or more of an object’s attributesat specific frames in time. These keyframes set the values, while tangentsset at each key determine the interpolation in between the keys. This inter-polation results in an animation curve that can be edited in the Graph Editor.This editing feature helps you control the quality of your motion.

Step 1: keyframesKeys are set for at least two points intime. You can set keys for one or moreattributes at the same time. The keys arethen stored as animation curves.

Step 2: Animation Curve ShapeIn the Graph Editor, you can view and editthe animation curves. At each key, thereare tangents set that define the shape ofthe curve.

Step 3: PlaybackWhen you play back an animation, the objectuses the keys and the values defined by theanimation curve to create the resulting motion.

Keying AttributesIn Maya, virtually every attribute iskeyable. As you learn more aboutthe different nodes available inMaya, you will begin to discoverunique possibilities for animatingyour models. For example, if youkeep an object’s ConstructionHistory, you can set keys on theInput node’s history. You can alsoset keys on attributes belonging tolights, materials, cameras, andother node types.

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How To Set KeysThere are a number of ways to setkeys in Maya. Each one offers a dif-ferent way of recording time andvalue information. In some cases, youmay want to set keys for a number ofobjects, and in others, you may wantto set keys for a single attribute. Theresults are always the same as anima-tion curves are created for anyattribute for which you set akeyframe. The only difference lies inchoosing a workflow that meets yourneeds.

Channel boxThe Channel Box always displays the keyable attrib-utes of a selected object. The Channel Box also letsyou highlight one or more channels and then selectChannels > Key Selected to set keys for the highlight-ed attributes on all the selected objects.

Attribute EditorWhen viewing attributes in the Attribute Editor, you canclick the right mouse button over individual attributesand choose Set Key. Since this window shows bothkeyable and non-keyable attributes, you can use thismethod if you need to key an attribute that does notappear in the channel box.

Auto KeyAuto Key lets you key automatically as you editobjects in your 3D views. Auto Key will set keys when-ever the value of an animated attribute is changed.Make sure to turn this option off when you have fin-ished using it.

Set KeyThe Animate > Set Key tool is designed to createkeys for as many keyable attributes that existon selected objects or characters. If a characteris selected from the character pop-up then it iskeyed. Otherwise the selected object is keyed.

Prompt One of the Set Key options is to use a prompt window tolet you set the keys for multiple points in time. Forexample, you could set a key for frames 5, 10, and 15all at once using this window. The same attribute valuewould be keyed for each of these times.

Selected Keys

Selected Character

Autokey Off AutoKey On

Hot KeysA fast and easy method for setting keys is throughHot Keys. Hitting the s key will set a keyframe for allkeyable attributes on the selected object or charac-ter set. Shift w, Shift e, Shift r, will set keys forjust the translation, rotation, or scale of an object.

Modeling is the process of creating shape and form

on screen. Models in Maya can be hard objects with

sharp edges or organic objects with a softer look.

Using one of several geometry types, 3D artists

can build surfaces, then push and pull points to

change their shape.

Modeling on the computer can be a challenge at

first because the goal is to mimic three dimensional

objects on a two dimensional screen. In this chapter,

3D artists will learn how to use manipulators and dif-

ferent view panels to navigate this virtual world so

they can focus on sculpting and building their models.

While building good looking models is important, 3D

artists must also be aware of how the model will be

used down the line. Models might need to bend or twist

or simply move around your scene. Also, how surfaces

are texture mapped will depend on how they were built.

Therefore, 3D artists must make important choices at

the outset about what kind of geometry they need and

how it will support their animation pipeline.

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GeometryThe mathematics of geometry is used by the computer to determine

what you see on the screen. Maya’s user interface gives you toolsto edit geometry without having to understand the math behind it.

In order to build complex scenes, you need to understand how tomanipulate geometry and how the geometry will be animated and tex-ture-mapped down the line. A good-looking model is only complete whenit satisfies the needs of all aspects of the animation process.

Points, Curves, andSurfacesPoints, curves, and surfaces arethe basic geometric elementsthat you will use to create andmanipulate 3D objects on thecomputer.

The creation of surfaces frompoints and curves is the essenceof modeling in Maya. Sometimes,you start with an existing sur-face and manipulate its pointsto define shape and form. Othertimes you start with carefullyconstructed lines or curves thatare then used to build a sur-face. Either way, you will workto give a physical presence tothese basic geometric elements.

PointsPoints are defined in three dimen-sions using XYZ coordinates. InMaya, control points are used tohelp define the shape of objecttypes such as curves (CVs), sur-faces (vertices, edit points), andlattice deformers (lattice points).Points are also very useful as ref-erences for snapping.

CurvesWhen two or more points are connected, youhave a curve. Curves are useful for definingthe shape of an object. They can also be usedas paths for animating objects. Since curvesonly have one dimension, they cannot be ren-dered. Instead, they can play a key role indefining how surfaces work in 3D space.

SurfacesWhen a series of lines are connected in twodirections, you have a surface. Surfaces canbe textured and rendered to create 3Dimages. When you shine light onto a sur-face, you can see the shape of the surfaceas gradations of tone and highlight.

ObjectsOne surface is often not enough to fully define an object in3D. When a series of surfaces are positioned in relation toeach other, you begin to get more complex models. Thesemodels require grouping to bring together the parts into aselectable hierarchy that can work as a single object, whilenot denying you access to the individual parts.

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NURBSNURBS geometry is spline-based. The geometry isderived from curves andsurfaces approximatedfrom the surface’s controlvertices (points) locations.NURBS allow you to startwith curves that are thenused to generate surfaces.This workflow offers precise results that can beeasily controlled. All NURBSsurfaces are four-sidedpatches, although thisshape can be altered usingthe Trim tool.

SubdivisionSurfacesTo create objects withSubdivision surfaces, youneed some understandingof both NURBS and polyg-onal modeling.Subdivision surfaces aremostly built using a poly-gon mesh as a base andthen refined. The advan-tage of using this geom-etry type is that detail isadded only where need-ed, and it createssmooth surfaces likeNURBS but does not havethe limitations of beingfour-sided patches.

PolygonsPolygons are shapes defined by vertices that create three, four or n-sided shapes.Polygonal objects are made up of many poly-gons. Polygons can appear flat when ren-dered, or the Normals across adjacent facescan be interpolated to appear smooth.

Geometry TypesOne of the first decisions you have to make when you start aproject is how you are going to build your models. There arefour types of geometry– polygons, NURBS, Subdivision, andBezier surfaces.

You can use any geometry type to create either simple orcomplex models. You can use one geometry type as a startingpoint for another or you can build models that combine geom-etry types. In general if you are building organic shapes, youwill probably use NURBS or Subdivision surfaces. They will giveyou smooth surfaces and have the fewest control pointswhich make edits to the surface easier. Since NURBS are

limited to a four-sided patch, there are limitations to thetypes of organic shapes you can make from a single surface.This is where it is beneficial to use Subdivision Surfacesbecause they can represent many more types of shapes with asingle surface. If you are building non-organic shapes suchas a desk, or wall, it is easier to use polygons because theyeasily make shapes like corners or edges. If you are buildinga surface that combines hard edges with an organic shape,Subdivision Surfaces work well. In this chapter, you will learnmore about your options so you can decide on the geometrythat best suits the way you want to work.

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NURBS Curves

Curves are an important tool for working in 3D. They can pro-vide a simple shape for modeling a surface or controlling aninverse kinematics (IK) solution. You can use them to cut

holes in a surface or as a path for animating an object.

Anatomy of a curveA Non-Rational Uniform B-Spline (NURBS) curve is defined by control ver-tices (CVs) that control the shape of the curve. The resultant curveapproximates the path drawn through the CVs. NURBS curves also haveother types of control such as edit points and hulls that help you workwith and understand the shape of the curve.

Control Vertices (CV)These points define the shape ofthe curve. Depending on thecurve’s degree, the CVs will con-trol the curve differently.

Knots and Edit PointsKnots are points that exist only in thecurve’s parameter space that define theend points of curve spans. Edit pointsgive you selectable components that letyou move the positions of knots in XYZspace. Multiple knots at one point inparameter space may cause a break inthe curve’s continuity.

Curve directionThe start of a curve isdefined by a square boxand a small U defines thedirection of the curve.

HullsThe hull shows you straight linesconnecting adjacent CVs of acurve. When you select a hull, youare actually selecting all of itsassociated CVs.

When a curve is usedto build a surface,the curve’s numberof spans have adirect influence onthe topology of theresulting surface.

Curve PointYou can select a Curve point that represents ameasurement of U along thelength of the curve. The U value of this point isdependent on the parame-terization of the curve.

SpanA span is one section of the curve. Each span is like itsown little curve that has a continuous relationship withneighboring span.

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Circle and Square These primitive shapes cre-ate History nodes for edit-ing attributes such aslength and radius. You canedit these using the ShowManipulator tool or in theChannel Box.

Edit PointCurveDrawing a curvewith edit points, allows you toaccurately snap the points toother curves to make sure theyintersect. Drawing this type ofcurve is quite different than aCV curve.

CV CurveThis tool lets you create acurve with very fine con-trol over its shape. Sincethe CVs lie off the curve,except at end points, youdon’t have direct controlof the positioning of editpoints.

PencilThe pencil line draws acurve by capturing yourmouse stroke. This tool isgood for getting rougher-looking lines but may generate too many CVs.You may need to rebuildthe curve later.

2- and 3-Point ArcThese tools let you controlthe shape of the arc. Radiusinformation is available andlater you can edit the archistory using the ShowManipulator Tool.

TextThis tool creates NURBS curves that outlinetext using any of the fonts available on your system. You can also importoutlined text from a vectorbased application.

Curves-on-SurfaceWhile most curves are created in the XYZcoordinate world, some curves can bedrawn directly on a surface. These curves-on-surface live in the UV coordinate spaceof the surface. These curves are oftenused to to add a hole or a more complexedge to a NURBS surface by trimming thesurface. Curves-on-surface can also beused as motion paths so that objects ani-mate along the surface.

ProjectingYou can project acurve that lies in 3Dspace onto the sur-face. This creates acurve-on-Surfacethat lies within theUV of the surface.

You can also get a curve-on-Surface by intersecting two surfaces.

DrawingYou can use theMake Live button toallow you to draw acurve into the sur-face’s UV space. Youcan also edit controlpoints in UV.

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NURBS SurfacesThe foundation of a NURBS surface is the NURBS curve. To create NURBS surfaces efficiently,

you must be proficient in creating good curves. The same principles behind NURBS curves areapplied to NURBS surfaces since the two are related. There is an obvious difference: a NURBS

curve has only one direction, while the NURBS surface has two directions. The two directions on aNURBS surface have an origin and together they define the Normals of the surface which determinethe front and back of the surface. Being aware of these surface properties will help when usingcertain modeling and rendering operations such as Attaching surfaces or texture placement.

Anatomy of a NURBS SurfaceThe components of the NURBS surfaceare very similar to those of the NURBScurve, except the edit points are notmoveable. NURBS surfaces have CVs,hulls, and spans which define theshape of a four-sided surface. NURBSmodels, whether they are organic orindustrial in nature, generally aremade up of several adjoining foursided patches. As with the NURBScurve, it is desirable to define sur-faces with the fewest evenly spacedisoparms or CVs. As earlier stated, thequality and type of curve will affectthe characteristics of the surface.However, the surface parameteriza-tion can be modified after creation byduplicating the surface curves at thedesired locations and re-lofting.

Control VerticesThey do not exist on theactual surface but areused to manipulate theshape of the surface.

SpansA span or segment is the spacebetween isoparms at editpoints. When creating surfacesusing Revolve, Primitives, andLoft, or rebuilding them, youcan specify the amount ofsegments or spans.

IsoparmsIsoparms are lines that represent cross-sections in the U and V directions.Isoparms can be inserted, removed, usedto make curves, and snapped to. If youselect an isoparm that's not a span or section, it displays as yellow dots.If you select an isoparm thatis a span or section, itdisplays as a solid yellow line. This distinction isimportant forsome modelingactions.

Surface OriginTurning on this display optionhighlights the first U and Visoparms (red and green) andlabels them U and V. It also drawsa line indicating the surfaceNormal direction (blue).

HullsThe hull comprisesstraight lines thatconnect CVs. Whenyou select a hull,you are actuallyselecting all of itsassociated CVs. thehull offers a bettervisual cue for thedistribution of CVs ina crowded area.

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Building SurfacesThe majority of the surfacing tools begin with creating curves defining the surface.In some cases the curves are used to create simple surface which are then rebuilt andmodified by CV manipulation. Other times the curves are used to create much morecomplex surfaces that would be difficult to attain otherwise. To help you understandthe operation of the tools, view the HelpLine as you scroll through the menus.

Birail SurfaceThe Birail Tool creates a surface byusing two or more profile curvesthat sweep along two rails. Theprofile curves must intersect the rail curves tocreate a surface. Profile and rail curves can beisoparms, curves-on-surface, trim boundaries,or boundary curves of an existing surface. Theadvantage of this tool over the Loft is greatercontrol with the addition of rails.

Fillet Blend SurfaceThe Fillet Tool creates a seamlessblend between two surfaces. Thethree types are: Circular Fillet,Freeform Fillet, and Fillet Blend. Theseterms are discussed later in this chapter.

Loft Surfacea Loft surface is created when asurface is applied to a series ofprofile curves that define a frame.There must be at least two curves or sur-face isoparms, and ideally the same para-meterization for each curve, to achieve aclean surface. If the curves have the samecurve degree and parameterization, theLoft surface will have the same number ofspans in the U-direction.

Revolve surfaceThe Revolve tool creates asurface defined by a profilecurve that revolves around adefined axis. The use of constructionhistory is very useful to tweak theshape after the revolve operation.The front fender began as a revolvedsurface that was then scaled,deformed and finally trimmed. Thetire and rims are simple revolves.

Trim SurfaceTo create a trimmed surface,a closed Curve on Surface isrequired. There are various ways of cre-ating these curves which will be dis-cussed later in this chapter.

PrimitivesNURBS primitives are com-mon geometric objectssuch as spheres, cubes, and cylin-ders. Primitives are often used as thefoundation for other shapes.

Extrude SurfaceThe Extrude tool creates asurface by sweeping a cross-sectional profile curvealong a path curve. The profile curve can be an openor closed curve, a surface isoparm, a curve-on-sur-face, or a trim boundary. The extruded surface onthis model create a lip for the scooter surfaces andgive the illusion of depth.

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Polygon Modeling

Polygons can be defined as a number of connected points that create a shape or face. Pointsare connected by edges that surround the resulting face. A face can exist as triangles, quad-rangles (quads), or n-gons. Joined together, they create a polygon mesh. A polygon mesh can

either consist of the Primitives that come with Maya, can be a complex shape that results from usingMaya’s polygon editing operations, or can be a mesh resulting from a Nurbs to Polygon conversion.

Polygon ComponentsEach polygon mesh consistsof components that aremodifiable to help createand edit the mesh. Thesemain components are ver-tices, edges, faces, andUVs. There are polygonediting operations in Mayathat allow you to editthese components. Whileyou will need to select theindividual components youwish to modify, by settingConvert Selection to On inthe Polygons > ToolOptions menu, Maya willautomatically switch tothe right component typefor a given edit operationand perform the operationas instructed.

EdgesEdges connect vertices by draw-ing a straight line betweenthem. A single edge can bemoved, scaled, or rotated.Press F10 for Edgeselection mode.

Selected Edges

Selected Vertices

Selected UVs

Selected Faces

Quad

Triangle

VerticesA vertex is a point in 3Dspace. Three or more con-nected vertices make aface. Press F9 for Vertexselection mode.

UVsUVs are the two-dimensional coordinates that are required todisplay or render a texture on a mesh. A UV directly correspondsto a vertex on the mesh. Press F12 for UV selection mode.

FacesA face is made up ofthree or more connectededges. A face with threesides is a triangle, withfour sides is a quad, andwith more than four sidesis a n-gon. A face can bemoved, scaled, or rotat-ed. Press F11 for Faceselection mode.

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Extruding FacesYou can further refine your shape by extruding the face of a polygon. This extrusion operation insertsfaces at the edges of the face to be extruded andallows the selected face or faces to be moved, scaled,or rotated from their original position. If you areextruding multiple faces and want them to maintain acohesive shape, set Polygons > Tool Options > KeepFaces Together to On. This only inserts faces at theedges on the border of the selected faces. Otherwise,faces will be inserted at every edge. This tool can befound under Edit Polygons > Extrude Face.

Splitting PolygonsThe Split Polygon Tool allows you to divide a polygonalface. You can also use the Tool to insert vertices on anedge. To assist you, the Tool has options that allowyou to set how many Snapping Magnets you want andthe Snapping Tolerance for the magnets. By settingSnapping Magnets to 3, the edge being split will havethree equally spaced division points. Increasing theSnapping Tolerance increases the influence of the mag-nets. With a Snapping Tolerance of 0, the vertex can beadded anywhere on the edge. A tolerance of 100 willforce the vertex to snap directly to the division points.

Face four is selected. This isthe face that will be extruded.

A common use of the Split Polygontool is to divide a face in half. Thisis done with a tolerance of 100.

However, the face can be splitanyway you want as long as thelast vertex ends up on an edge.

After the extrude is completeyour faces are added at theedges of the extruded face.

Polygon PrimitivesMaya includes a number of polygon Primitives that can give youa starting point for your model. These Primitives, with theexception of the plane, are closed shapes and all Primitivesare created with a default set of UV information. ThesePrimitives have construction history and their subdivisions canbe modified before or after creation.

Sphere Cylinder TorusPlaneConeCube

Polygon CreationTo create a polygon shape,select Polygons > CreatePolygon Tool. After placing apoint, use the middle mousebutton to alter its position.

1st Click

4th Click

5th Click

2nd Click 3rd Click

After the 3rd click, the polygoncan be completed by pressingEnter. The dashed line repre-sents the final edge.

You can continue to place pointsuntil the desired shape isachieved. Press Enter to finish.

In the real world, some objects are hard and some

are soft. The surfaces on the soft objects can be bent

and folded into different shapes. This kind of surface

deformation can be set up and animated in Maya.

Pushing and pulling the control points on a

surface deforms its shape. Yet, to sculpt every surface

point-by-point can be time consuming. Maya offers

deformation tools that give 3D artists a higher level of

control. A deformer can be applied to one or more

objects and then a few control points or attributes can

be edited to get bending and twisting.

Deformers can also be used as modeling tools

because they are great for reshaping a surface. In the

end, by deleting the construction history on the sur-

faces, the deformer disappears, leaving the new

twisted surface.

The deformer attributes or control points can be

animated to reshape an object over time. Deformers can

also be bound to skeletons to help animate characters.

Simulated deformations can then be used to create

realistic draping and cloth effects.

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Deforming Objects

Many objects in our 3D world are able to changetheir shape – a soft chair gives as someone sits init, a rubber ball squashes and stretches as it hits

the ground, human skin bends as the elbow rotates. Toachieve these kinds of effects in Maya, surfaces have tobe able to have their shape animated. This means animat-ing the positions of control points instead of simplytranslating and rotating the object.

A face with no deformations.The same face after using sur-face deformation to reshape thenose,add a smile, round out thecheeks, widen the chin, andmake folds for eyelids.

Types ofDeformationIn Maya, there are a numberof ways to change or deformthe shape of an object.These deformers can beused to help you model sur-faces or animate organicforms. While there are a setof tools in Maya calleddeformers, there are othertools that change the shapeof objects. By becomingfamiliar with all of thesetechniques, you can bestdecide which one can beused in your work.

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CV and Vertex EditsThe most rudimentary method ofdeforming a curve or geometry is toselect component level control pointsand translate, rotate, or scale them.This is useful when you need to move asurface point to a specific location.

DeformersMaya has a category of tools calleddeformers that either perform a specifictype of surface deformation such as twistor bend, or make the process of deform-ing a surface easier in some way. Forexample, a lattice is a cage-like manipu-lator made of a small number of latticepoints. Each lattice point controls severalcontrol points in a specified region of thesurface. Moving one lattice point canaffect many control points on the surfacethat would be difficult to select and moveindividually.

Simulated DeformationsMaya has features for simulatingproperties of clothing and softdynamic moving materials like cur-tains, flames, and flags. A softbody is a geometry object whosecontrol points are controlled byparticles and dynamic fields such asturbulence and gravity.

Skeleton ChainsA skeleton chain consists of joint nodes thatare connected visually by bone icons. Skeletonchains are a continuous hierarchy of jointnodes that are parented to each other. Youcan group or bind geometry (skin) to thesejoint hierarchies. You can then animate thejoints (usually by rotating them) and the geom-etry will be animated. Binding geometry to askeleton causes the geometry to be deformedas the skeleton is animated. For example, youcould rotate a neck joint and the geometryaround the neck joint would rotate as well.

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Non-linear Deformers

Non-linear deformers control the deformation of the surface using simple deformation“handles.” These handles have easy-to-use attributes that can be changed toaffect the characteristics of the deformation for each different non-linear

deformer. These deformers are great for modeling objects into otherwise hard to formshapes and can also be used to animate the shape of the object to give it character.These deformers can be applied to polygons, NURBS, and Subdivision surfaces.

There are six non-linear deformers in Maya: Bend, Flare, Sine, Squash, Twist, and Wave.These deformers can be applied to an object by selecting the geometry, then choosing adeformer from Deform > Create Nonlinear.

The term non-linear is used because the amount of deformation does not necessarilyhave to be the same across the entire surface. For example, if you have a model of a treethat you want to sway in the wind, you can make the trunk of the tree bend more at thetop and less at the bottom. This ability to control deformation “dropoff” and regions ofdeformation is built directly into most of the non-linear deformers.

Modeling with Non-linear DeformersThe drill bit begins as a scaled NURBS primitive sphere withhigh detail. The Control Vertices (CVs) on the top “pole” ofthe sphere are selected and moved to elongate the drill bit.The shape is then flattened by scaling. Detail is added at thetip by manually adjusting CVs.

A Twist deformer is added to the overall shape. The geom-etry becomes pink when selected,indicating that the surface isconnected to the deformer. The effect of the twisting is localizedto influence only a specific region of the geometry by adjusting thedeformer handle. As a result, the twist coils become more compressed andthe finished shape is produced.

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Twist

Flare

Squash

Bend

ManipulatorsEvery non-linear deformerhas a manipulator handlethat lets you deform inter-actively. To access a han-dle, select it, click on theShow Manipulator Tool,then click on the deformerin the Input section of theChannel Box.

FlareThe neck of the drill is acylinder that is stretched andwidened using a Flaredeformer. This is an examplewhere a deformer is used tomodel a shape. Bend

The drill handle isshaped using aBend deformer.

SquashAs the drill handle cranks, an animatedSquash deformer can be used to bulgethe body of the drill. This helps addcharacter to the object.

TwistThe drill bit is mod-eled by applying aTwist deformer to a sphere.

High and Low BoundsIt is possible to influence theextent to which a deformeraffects a surface. The High andLow Bounds let you define thedeformed region of the surface.There are manipulators to helpwith this task. Click-drag anywhere on

the circle to change theEnd Angle of the twist.

Click-drag anywhere onthe circle to change theStart Angle of the twist.

Click-drag on the center ofthe circle to change the HighBound. This defines the endof the surface region thatthe deformer will influence.

Click-drag on the center ofthe circle to change the LowBound. This defines thebeginning of the surfaceregion that the deformer willinfluence.

One of the most challenging and rewarding forms

of computer animation is character animation. Here,

3D artists combine the transformation of a digital

skeleton with the deformation of a skinned surface,

to set up a character that walks, talks, and moves

around in 3D space.

Of course, a character doesn’t have to be a

human or an animal. Any object that is animated

with expression and tries to speak to the audience

through its actions is considered a character. In

fact, the same techniques used to animate a dog

might be used to animate a dancing bottle, a tiger

or a tree.

Maya allows you to combine all the controls

found on different parts of a character into one or

more character sets. This makes it easier to pose

characters and work with them in Maya’s non-linear

Trax animation system. These techniques help 3D

artists set up characters that can be animated

throughout a production with consistent and

easy-to-use controls.

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A3D character is a digital actor.Whether your character is a tin canthat bounces with personality, or a

photorealistic human being, the animatorwill need to control it easily, and inter-actively. The specific requirements ofthe character's motion will dictate thecomplexity of the character's controls.Maya offers many tools forthe creation of thesedigital performers.

A Typical Character Animation WorkflowThe development and animation of a 3D characterinvolves a number of steps. Once you have a design, youmust begin to build the character’s model, lay downskeleton joints, and rig the skeleton so that it is capa-ble of an appropriate range of motion. Character con-trols can also be set up to assist the animation process.

While it is possible to work in a linear fashion, start-ing with modeling and ending with rendering, most pro-ductions require some form of concurrent work to bedone. An animator might need to begin laying down

motion while the model is still being fin-ished. At the same time, character defor-

mations and texture maps may each beassigned to different parts of a team.

For this reason, you may use yourlow-resolution character to begin

animating and blocking outscenes while the higher resolu-

tion character is refined andset up for deformations

and rendering.

Character DesignIn support of thestory, the character isdesigned usingsketches, story-boards, and in somecases, clay models.These visual aids givethe 3D artist a clearunderstanding of thecharacter and thecharacter’s range ofmotion and emotion.

RenderingThe final character is ren-dered in its final setting.You might also render thecharacter on its own, thenuse a compositing packageto integrate it with thebackground.

ModelingUsing thesketches, adetailed model isbuilt with an awarenessof how it will be boundto the skeleton later.

BindingSkeletonThe surfaces arebound to the skeletonand joint rotations tested.Deformers are used toenhance the final look.

Skeleton RiggingUsing sketches or themodel as a guide, jointsare drawn and kinemat-ics and character con-trols are set up.

AnimationA fully rigged model thatuses low-resolution sur-faces parented to theskeleton can be used forinitial animation studies.

IntegrationThe animation from thelow-resolution charac-ter is applied to a fullyrigged skeleton withbound surfaces anddeformers.

3D Characters

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Skeleton JointsJoints are used to create aframework for a character’shierarchy. The rotation of theskeleton joints defines themotion of the character; youcan use inverse kinematics foreven more control.

Selection HandlesSelection Handles give you quickaccess to parts of a character’shierarchy that are to be animated.This makes it easier to work with acharacter after it has been riggedup for animation.

Bound SurfacesSurfaces of a character’s skinand clothing can be either par-ented or bound to the skeletonjoints to make them movetogether. Binding places pointsfrom a surface into clustersthat are then associated withparticular joints.

DeformersTo help the surfaces bendrealistically at joints, deform-ers such as flexors and influ-ence objects can be used.

Character ControlsUsing animation techniques suchas Set Driven Key and expres-sions, you can set up attributesfor controlling different partsof a character. For example, ahand joint could have attributesused to control the differentfinger joints.

Facial AnimationTo animate facial features,you can use deformers suchas Blend Shape to createfacial poses that can beused for talking and forshowing emotion.

ConstraintsIt is possible to constrain the kine-matic controls of a skeleton toobjects in your scene or even simplelocators. You can then animate theconstraint weights to make a charac-ter pick something up or grab hold ofa fixed object.

KinematicsTo control your skeleton joints,you can choose from forward orinverse kinematics. ForwardKinematics allows you to set thejoint rotations directly. IKallows you to position IKHandles, which rotates thejoints.

A Typical CharacterThe character’s mechanicsmust be convincing to anaudience and the skin andclothing must also move andbend properly. Maya includesa number of tools that helpyou manage the parts thatmake up a typical character.This process of preparingcharacter controls is calledrigging and is used to let theanimator focus on the processof animating. A fully riggedcharacter can be quite com-plex as it brings togetherskeleton joints, surfaces,deformers, expressions, SetDriven Key, constraints, IK,Blendshapes, etc.

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Skeletons

Skeleton ChainsSkeleton chains are hierarchies of nodeswhere the pivot point of each node is repre-sented by a joint. The joint acts as a parentnode for the hierarchy below. The joints arethen connected using bones that help youvisualize the hierarchical relationships in the3D views. The resulting skeleton lets you buildup a framework that can mimic the skeletalsystems found in real humans and animals.

The most important thing to remember aboutskeleton joints is that they are part of a hier-archy and contain many of the properties of atypical Transform node. Therefore, you canmove their pivot points, re-orient their localaxes, and assign Selection Handles for easiercontrol. A skeleton is made up of joints. The

joints are the Transform nodes of atypical character hierarchy.

To give your characters a framework, skeletonjoints can be drawn in 3D space to representthe bones of your character. These bones

help you define and animate characters and arecapable of a wide range of motion when combinedwith kinematic tools.

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Grouped ObjectsWhen computers were first used to repre-sent crude characters, each segment of alimb was built separately, then parented tothe next limb in a hierarchical relationship.The pivot point of each limb object repre-sented its joint. The rotation of the limbsdefined the motion.

JointsTo help animators organize body parts,skeletons are used to define the limb hierar-chy. Joints represent the rotational pivotpoints and bones represent how joints areconnected. Rotating the joints defines themotion, but joints and bones don’t render.

Parented ObjectsFor renderable limbs, you can parent surfacesinto the skeleton hierarchy. The skeletongives you control. This technique is fast and isgood for non-deforming surfaces such asarmor or the limbs of a robot. This method isalso used for low-resolution characters wherespeed is paramount.

Deforming ObjectsRealistic characters have joints that bend.To create a surface that deforms with theskeleton, you can skin or bind a single sur-face or a patch network to the skeleton.This results in CV sets that can be weightedfor smooth bending of the joints.

Drawing SkeletonsThe Joint tool is used to draw skeletons. Each click adds anew joint to the scene. Bones are drawn between each jointto help you visualize the hierarchy.

As you draw, you can click on the Up arrow to go to ajoint higher up in the hierarchy. As you continue drawing,the new joints branch off from this joint.

When a joint branches off, it appears as if you can workwith the two bones independently. When you select the bonesconnected to the branching joint,you select a single joint which controls all the connected bones.

BonesBetween each joint is a bonewhich is drawn like a cone. Thiscone always points down theskeleton chain to the nextjoint in the hierarchy.

JointsThe joints are drawnas small circles thatrepresent the axesof the joint.

Insert KeyAs you draw joints, press theInsert key to edit the jointposition. Press Insert againto continue drawing. You canalso use the Middle mousebutton to reposition jointswhile drawing.

Pick-WalkingAs you draw joints, you can pressthe Up, Down, Left or Rightarrow keys on your keyboard tomove around your hierarchy. Thenext joint you draw will branchoff from the selected node.

While geometry describes the shape of an object,

its material describes how its surface will appear

when rendered. In the real world, when light hits a

surface it reacts to the surface qualities. Some of

the light is absorbed and some is reflected. A shiny

object reflects light directly while a matte object

diffuses the light. While reflected light does not

actually illuminate other surfaces in Maya, materials

and textures can be set up to simulate the real-

world reaction of surfaces to light.

To create realistic images, material qualities such

as color, specularity, reflectivity, transparency, and

surface detail must all be set. Maya uses special

connected nodes called Shading Networks to set up

the material qualities of your surfaces.

Textures let 3D artists create more complex

looks for their surfaces. A texture can be a set

of procedures set up in Maya or a bitmap image

created outside Maya. In either case, realistic

surfaces are created by combining geometry with

well-designed textures.

materials and textures

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Shading Your Models

While geometry defines the shape of a model,shadingdefines how the model’s surfaces react to light anddetails such as color, transparency, and texture. Maya

uses Shading group nodes to tell the renderer which materi-als, textures, and lights will affect the final look of a sur-face. Shading networks are made up of nodes that define thefinal look of a rendered surface. Learning the proper role ofeach of these nodes will ensure that you build shading net-works that render successfully.

SpecularHighlights

Reflections

TransparencyIt is possible to see through transparent areassuch as the glass on this jar, while opaque areassuch as the label, cap, and paint remain solid.Transparent surfaces such as glass can also bendlight. This is called refraction and can beachieved in Maya using Raytracing.

Material QualitiesBefore actually looking at a morecomplex shading network, it is use-ful to consider the various materialqualities that you will be trying toachieve. A basic understanding ofhow an object is shaded can betranslated into attributes on shad-ing network nodes in Maya.

Surface ReliefSurface relief, such as bumps andscratches, helps add a realistic lookto a surface. This effect can beachieved with special texturescalled bump and displacement maps.

Basic ShadingShading shows you how the surfaceappears when illuminated. As light hitsa surface, it defines a gradation fromlight to dark that makes the surface’s3D qualities apparent.

Highlights and ReflectionsAs a surface becomes shinier, it begins to showhighlights and reflections. Specular highlightsshow the hotspots where the light sources arereflected, while reflections simulate lightbounced from surrounding objects.

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The Anatomy of a Shading NetworkShading networks are built as nodes that control specific aspects of the shading effect. These networks define how various color and texture nodes work with associatedlights and surfaces. The placement of textures on surfaces is also controlled by nodes withinthe network.

There are several ways to view shading networks in Maya. The Hypershade window lets youeasily connect nodes and view the connected attributes. You can also double-click on any nodeto open the Attribute Editor. Along the way, you can zoom in and out in the Hypershade toget the complete picture. You can also view shading networks in the Hypergraph window butthis view does not give you swatch images.

3D Texture Placement NodeThis node lets you define a position in3D space for your texture and makes iteasier to texture multiple surfaces asif they were one. Theicon in the mod-eling views canbe used to inter-actively establishthe texture’sposition in worldspace.

2D Texture Placement nodeA texture is mapped in 2D spacewhen it is mapped to the UV spaceof the geometry. This node isused to define the tex-ture’s positioning andorientation within theUV space.

Material NodeMaterial nodes define how thesurfaces will react to light. Theterm shader is often used to

describe the role played by theMaterial node. In general,

this node will be thefocus of your work asyou build up all ofyour shading net-works.

Shading GroupThis node is the root of theshading network. It sendsinformation about materialsand textures, lighting, andgeometry to the renderer. Inmost cases, you will not haveto work directly with theShading group node becausethe Material node is where youwill make most of your textureconnections.

Environment TextureNodeAn environment texture isused to simulate reflectionson the surface. This nodemight be shared among sev-eral shaders and have anaffect on many surfaces.

File Texture NodeFile textures are bitmap imagesimported into Maya that can be usedfor texture mapping attributes suchas color, bump, or transparency.

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Materials in the real world react to light by absorbing orreflecting it. Polished surfaces are shiny because theyreflect light with strong highlights, while rough surfaces

have a softer look because they disperse light. A Material node isa mathematical shading model that simulates a natural reactionto light.

The Material node contains a number of attributes that letyou control how surfaces are shaded. Maya includes severalmaterial types, such as Phong, Blinn, and Lambert, that eachdefine a different shading model. The Material node acts as afocal point for shading and texturing information. It is then fedinto the Shading group node where it is combined with informa-tion about lights and the geometry to be rendered.

Material QualitiesThe behavior of light when it strikes a surface in real life isquite complex. Surface imperfections can distort the angle atwhich light rays are reflected causing them to scatter and canalso cause some light to become trapped, or absorbed. This typeof scattered reflected light appears soft and even and is knownas diffuse light. Very smooth surfaces have little or no surfaceimperfections so light is not absorbed and reflected light is morecoherent or focused. When this light reaches our eyes, we seebright specular highlights. These real world behaviors are simu-lated in Maya with the Diffuse and Specular attributes.

The Material nodes have attributes intwo main sections. Common MaterialAttributes are found on most Materialnodes while the Specular ShadingAttributes change, depending on thechosen material type.

Surface Materials

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BlinnMany artists use this material type exclusivelybecause it offers high-quality specular highlightsusing attributes such as Eccentricity and SpecularRoll Off. This material type can be edited to looklike a Phong material, which has sharper high-lights, in cases where you need better anti-alias-ing of highlights during an animation. This materialis good for glass and metals.

AnisotropicThis material type simulates surfaces which havemicro-facet grooves and the specular highlighttends to be perpendicular to the direction ofthe grooves. Materials such as hair, satin, andCDs all have anisotropic highlights.

PhongThis material adds a sharp specular highlightto the Lambert material. The size and intensityof the highlights are controlled by the CosinePower attribute. This material can also havereflections from either an environment map orRaytraced reflections. The Phong material isgood for plastics.

PhongEThis material type adds a different kind ofspecular highlight to the Lambert. ThePhongE material includes attributes such asRoughness that controls the softness ofthe highlight, Whiteness that controls itsintensity, and Highlight Size.

LambertThis material type is the most basic and doesnot include any attributes for specularity. Thismakes it perfect for matte surfaces that do notreflect the surrounding environment. TheLambert material type can be transparent andwill refract in a Raytrace rendering, but withoutany specularity, it won’t reflect.

Ramptexture

Shading MapThis material type allows you to create custom shading on surfaces. Aramp texture controls the positioningand color of the shading and high-lights on the surface. If you want toemphasize the dark areas, simplydarken the lower end of the ramp.

Material typesSeveral different material types offer you distinct shading characteristics. The main differ-ence between them is how they handle specular highlights when rendered.

In the illustrations below, six of the most commonly used material types are compared.Texture maps on various attributes such as color, bump, and specularity will also have animpact on the appearance of the material.

When preparing a digital scene, lights and cameras playa very important role. Both lights and cameras make itpossible to view objects, and see them in a realisticcontext. Artistically, they both allow 3D artists to con-trol the look of their animation with the same creativecontrol as a live-action cinematographer.

In some ways, the most difficult aspect of usinglights and cameras in Maya is that the possibilitiesare endless. It is very easy to fly a camera around without a clear sense of purpose or add too manylights to a scene. The question is whether or not thecreative decisions support the story being told.Therefore, it is a good idea to consider how live-action movies make use of camera moves and lighting.

Another challenge for 3D artists is to integrateCG elements and live action footage. They must takelighting and camera properties from the real-worldand mimic them in a scene so the audience does nothave any idea the CG elements are even there.

digital cinematography

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How Lights Work

L ight affects the way in which wesee the world around us. Lightdefines the shape and form of

objects and spaces, while at the sametime, it works at an emotional level bysetting mood and atmosphere. Learningto control light is an important 3D skill.

Cinematographers use light to illumi-nate the objects in the scene whilesupporting the scene’s emotional con-text. The quality of the light in a digi-tal shot is equally important, althoughthe rules are different.

Spot Light AttributesThe spotlight’s Shape node containsattributes that control how the lightwill illuminate the scene. Since thespotlight contains the most attributes,it is used as the example here. Theother light types contain a subset ofthe Spot Light Attributes.

IntensityThis attribute determines howmuch light is emitted from thelight source. As you increasethe Decay and Dropoff values,you need a more intense light.

DecayThis attribute deter-mines how much the lightintensity diminishes asthe light gets furtherfrom its source.Therefore, if you chooseto use Decay, you needto increase theIntensity.

Penumbra AngleThis attribute creates an area atthe edge of the spotlight where thelight fades. A larger value here cre-ates a soft look for the light.

DropoffThis attributedetermines howmuch the lightintensity diminishesas it gets to theouter edge of thelight. This putsmore emphasis onthe light’s hotspot.

Cone AngleThis attribute deter-mines the width of thespotlight’s cone ofinfluence. The areasoutside the cone are notilluminated.

ColorYou can set RGB valuesfor the light beingemitted. This will havean influence on thecolor of your scene.

HotspotThe point where the light is most intense is referredto as the hotspot. You also know it as a specularhighlight. The look of the highlight is a result of theintensity of the light and the shading qualities of thesurface’s Material node.

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In the Real WorldThe film’s exposure to light is con-trolled by the camera.

1 Light is emitted from a source witha controllable intensity. Directlight is hard, while light bouncedfrom other surfaces is softer.

2 Light levels are meas-ured using a lightmeter to determine theproper exposure set-tings for the camera.

3 Camera controls suchas F-stop, shutterangle, exposure time,and film speed areset to control howmuch light is exposedto the film.

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To simulate a bounced light inMaya, you would need to usea secondary light such as anarea light or an ambient light.

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Real World vs. Digital CinematographyIn the real world, light bounces. Light starts from a light source such as the sun or a lampand is either bounced or absorbed by all surfaces. An object appears red because thegreen and blue light is absorbed while the red light is reflected. A cinematographer setsup lights, then measures the light levels, which include both direct and indirect light. Thisinformation is used to adjust the exposure settings of the camera.

In Maya, surfaces are illuminated directly by lights. There is no bounced light comingfrom other surfaces. This is because CG lighting doesn’t bounce. Here, film isn’t exposedto light and camera controls don’t need to be adjusted. Light levels are, therefore, con-trolled using the intensity settings of the lights themselves.

On the ComputerThe intensity of thelighting is controlled bythe lights.A From the camera’s

point of view, therenderer samples apoint on a surface.

B From the surface’sshading group, a listof associated lightsis used to determinewhich lights shouldbe factored in.

C The light’s attrib-utes, such as inten-sity, color, anddecay, are used tocalculate the illumi-nation on the sur-face.

Point

Light TypesMaya has several lighttypes, each of which illumi-nates a scene differently. Atypical scene combines anumber of different lighttypes. You can switchbetween light types inthe AttributeEditor.

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Casting Shadows

One of the most dramatic aspects of lighting is in the areawhere there is no light. Shadows add drama to your scenewhile helping to anchor characters and props to the

ground. If your character leaps into the air, you know what ishappening because the shadow and the character no longertouch each other.

In Maya, there are many factors that affect the look andquality of your shadows. You can choose from Depth Map andRaytraced shadows which offer different levels of quality andspeed. Sometimes light attributes, such as Cone Angle willaffect your shadows and must be taken into account. The moreyou know about how shadows are cast, the easier it will be toadjust the appropriate attributes.

Depth Map ShadowsDepth Map shadows are the more efficient of the two shadowtypes. A Depth Map shadow can be created by setting Use DepthMap Shadows to On in the light’s Attribute Editor.

Depth Map shadows work by recording the Z-depth informa-tion from the light’s point of view, then using this informationto evaluate whether or not a point in your scene is in shadow.The diagram below shows how a spotlight evaluates Depth Mapinformation to generate shadows. You can see that the DepthMap is generated from the light’s point of view.

With and Without ShadowsHere are two shots of a scene. The firstdoes not use shadows and the second onedoes. You can see how the scooter in thesecond image is much more grounded, and itis easier to read the scene’s depth. Whileshadows do require extra work when you setup a scene, they are well worth the effort.

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Step 1When a rendering starts, aDepth Map is created from thelight’s point of view that meas-ures how far the various objectsare from the light. White is usedto show surface points closestto the light, while the variousshades of gray show a greaterdistance from the light.

Step 3This measurement is thencompared to the depth information stored in theDepth Map. If the point’sdistance is greater thanthe distance stored inthe Depth Map, the pointis in shadow.

Step 2When a point on a surfaceis being shaded during therendering process, thedistance is measuredbetween the point and thelight source.

Step 4If the point is in shadow,the light’s illuminationdoes not contribute tothe shading.

Note: Another light, suchas an ambient light, mayilluminate parts of thescene where the spotlightdoes not. That is why youcan see the wood textureunderneath the chair inthis image.

Stored Depth Map Value

Raytraced ShadowsTo calculate Raytraced shadows, Maya sends aray from the camera and when this ray hits asurface, it spawns another ray toward thelight. This shadow ray reports whether or notit hits any shadow-casting objects on its wayto the light. If it does hit a shadow-castingobject, then the original surface is in shadow.

Raytraced shadows have the disadvantageof being slower to render than Depth Mapshadows. However, depending on the look youare interested in, there are several reasonswhy you would use Raytraced shadows in yourscene, these include transparent shadows,colored transparent shadows, and shadowattenuation.

If you want Raytraced shadows, but notreflections and refractions, then setReflections and Refractions to 0 in the RenderQuality section of the Render Globals.

A 3D artist’s ultimate goal is to create a sequence

of images that can be synchronized with sound and

played back as a movie. The creation of these images

is the job of the renderer where surfaces, materials,

lights, and motion are all taken into account and

turned into bitmap images.

The art of rendering involves finding a balance

between the visual complexity needed to tell a story

and the rendering speed that determines how many

frames can be rendered in a given time. Simple

models render quickly and complex models take longer.

Therefore, the render artist brings together all

the parts created throughout the animation pipeline

and ensures that they render with high quality as

fast as possible. This means exploring the interac-

tion of surfaces, lights, and materials and making

sure that the pixels look right in their final form.

rendering

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Rendering Scenes

Rendering is where all of the work in setting up models, textures, lights, cameras, and effectscomes together into a final sequence of images. In very simple terms, rendering is the creationof pixels that are given different colors in order to form a complete image. A render involves a

large number of complex calculations that can keep your computer busy for quite a while. The key atthis stage in the animation process is to find a way of getting the best image quality and thefastest render times so that you can meet your deadlines.

Before exploring the specific details of rendering animation sequences, it is important torealize that there are two different methods in Maya: software and hardware rendering. Thesoftware rendering process is considerably more complex and requires a great deal more knowl-edge and understanding to get the best results. The renderer is where all of your scene data andsettings are handed off to the software and render calculations are performed that result infinal bitmap images. To give you some insight into what Maya actually does with your scene dataduring this process, an overview of the software render process itself is shown on the next page.

Hardware RenderingHardware shading, texturing, and lightinguse the computer’s graphics hardware to dis-play objects on the screen. You can use theHardware Render Buffer to take snapshotsof each frame and save them to disk.

Because hardware is designed to per-form only specific tasks, its renderingcapabilities have the advantage of beingvery fast, but lack the sophistication offeatures such as shadows, reflections, andpost-process effects. Hardware renderingis used primarily to render hardware-typeparticle effects which are later enhancedin a compositing application.

Hardware ShadingYou can display hardware shading, texturing, and lighting in any viewpanel using the the panel’sShading menu.

Hardware Render BufferThe Hardware Render Buffer isa special window used for out-putting hardware-renderedimages.

70



Software RenderingThe software renderer uses complex algo-rithms to combine elements such as geome-try, cameras, and textures, with thephysics of light to create final bitmapmages. Because some aspects of light’s

true behavior would be prohibitively slow tocalculate, most renderers let you employshortcuts such as ambient lights in placeof global illumination to make sure thatrendering times support the productioncycle.

Software rendering has the advantageof being more flexible than hardware ren-dering. Software companies can add func-tionality by changing algorithms in the codewithout being restricted by the computer’shardware. Therefore while software render-ng is not as fast as hardware rendering,

the added functionality lets you achievemore sophisticated results.

Render ViewMaya’s Render View window allows you to launch a software render and watch theresults as the file is being rendered. It can be used for everything from a quick teston a low quality render to a final production render. However, because it only ren-ders the current frame, it is not used to render animation.

While rendering in the Render View window, Maya itself is the renderer; there is nointermediate file or separate rendering application as is the case with other render-ers. Consequently, Maya does not allow you to make changes to the open scene’sdata as it is being rendered.

Image ZoomBy default, images are automatically resized to fit intothe Render View window. This means that you may be see-ing your image at a zoom value other than 1.0. This scaledimage will appear jagged in most cases, making it look likeit has anti-aliasing problems. Press the 1:1 button to viewthe image at its true size. If you still see jagged edges,adjust the anti-aliasing settings in Render Globals.

Batch RenderingTo software render your animation,you will use the Batch renderer,which can be launched inside theMaya interface or from a commandline. When you start a Batch renderfrom within an interactive session,a scene file is saved and anothercopy of Maya (with no user inter-face) is launched to do the render.This means that you can keep work-ing on your scene in Maya while therender is in progress. For maximumspeed when rendering your finalanimation, you should render froma command line (for example UNIXshell, DOS command prompt window)with no interactive Maya sessionrunning.

The Render Globals attributes letyou specify the camera, anti-alias-ing quality, resolution, etc. for theBatch render. If rendering from acommand line, there are many flagswhich can be set to override anyRender Globals settings saved in afile. This can be very useful andefficient in cases where the scenefile takes a long time to open.

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Render Output

Based on your post-production requirements, your final renderedimage or sequence of images will need to suit the medium youare outputting it to. These image properties,such as size,

format, and frame padding, are set from the Render Globals Window.

Render ResolutionThe RenderResolution refersto the dimensionsof a renderedframe in pixels.Maya’s list of pre-sets allows you toquickly select aresolution from alist of those com-monly used in theindustry.

Image FormatsThe Image Formats pop-up list allowsyou to specify the format you needyour rendered frames to be in. Maya’s

online documentationhas a detaileddescription of howeach of these formatshandles image, mask,and depth informa-tion. The Maya IFF fileformat is also docu-mented. Some formatsare only available onsome platforms.

Renderable CameraThe pop-up Camera list allowsyou to choose which camera willbe used in the Batch render. It is possible to renderfrom more than one camera in aBatch render. This RenderGlobals setting does not affectwhich camera is used while rendering in the Render View window within Maya.

72



Rendering AnimationAn image file name consists of three components when rendering ananimation: file name, frame number extension, and file format exten-sion. (A combination of these three components is referred to as thefile name syntax.)

The file name is the base name for all images in the animationsequence. The frame number extension represents the frame in theTime Slider in which the image is rendered. The file format extensionindicates your chosen file format. You can see these combined as apreview at the top of the Render Globals window.

You need to tell Maya what frames to render when rendering ananimation. After a Start Frame and an End Frame are specified, Mayarenders all the frames in between by default. However, if you want torender every 10th frame for test purposes, you can set the By Frameattribute to 10. In this case, Maya only renders every 10th frame,beginning with the Start Frame number.

ChannelsThe color channels of arendered image are madeup of red, green, and blue(RGB). A mask channel (oralpha channel) stores informa-tion about the coverageand opacity of the objectsin your scene. This channelallows you to work withyour rendered images in acompositing software appli-cation like Maya Composeror Maya Fusion.

A depth channel recordsthe distance from the cam-era to the objects in thescene. This is often calledZ-depth and you can lookat it using the Z-key in F-check.

Maya can render an image file that containsRGB color information, a mask channel, adepth channel or any combination of thethree. The flags in the Render Globals windowlet you choose what channels will be rendered.Some image formats do not support embeddedmask or depth channels; in these cases, Mayagenerates a separate mask or depth file andputs it in the mask or depth sub-directory ofyour current project.

color (RGB)

depth

mask

Image FormatsMaya's Render Globals lets you render your images in the specific formatthat you need for your production pipeline. The default image format isMaya's IFF, but you can choose from a list of many standards used incomputer graphics such as TIFF, GIF, JPEG, Quantel, etc. Most of theformats are 8 bits per channel, but Maya also renders 10-bit Cineon andseveral 16-bit formats which are commonly used for film. Human eyescan perceive more colors than 8-bits can represent, so high-resolutionformats such as film sometimes require better color definition to lookrealistic.

Maya also lets you render directly to AVI or QuickTime movies. While thismay be convenient, you might also consider rendering in one of the otherformats that creates separate images so that you have more flexibility. Anapplication such as Maya Fusion allows you to create a movie from theimages after any adjustments have been made.

3D Computer Graphics 2

3D Computer Animation 3-4Technical Creativity 5-6The Animation Pipeline 7-8Computer System 9-10

Time and Space 12

3D Space 13-14Time 15-16Bitmap Space 17-18Color Space 19-20

Exploring Maya 22

The Workspace 23-24File Management 25-26Viewing 3D Scenes 27-28Objects and Components 29-30Dependency Graph 31-32Transformations 33-34Duplication 35-36Snapping 37-38Artisan 39-40MEL Scripts 41-42

Animation 44

Animation Techniques 45-46Setting Keys 47-48Animation Curves 49-50Hierarchical Animation 51-52Path Animation 53-54Non-Linear Animation 55-56Reactive Animation 57-58Rigid Body Dynamics 59-60

Modeling 62

Geometry 63-64Modeling Techniques 65-66NURBS Curves 67-68Working with Curves 69-70NURBS Surfaces 71-72Trims and BOOLEANS 73-74Joining Surfaces 75-76Polygon Modeling 77-78Subdivsion Surfaces 79-80UV Coordinates 81-82Construction History 83-84Patch Modeling 85-86Modeling for Animation 87-88

Deformations 90

Deforming Objects 91-92Non-linear Deformers 93-94Lattices and Clusters 95-96Simulated Deformations 97-98

Character Animation 100

3D Characters 101-102Skeletons 103-104Kinematics 105-106Skinning Characters 107-108Animating Characters 109-110Walk Cycles 111-112Facial Animation 113-114

table of contentsFrom the full edition of the Art of Maya book



Materials and Textures 116

Shading your Models 117-118Surface Materials 119-120Texture Maps 121-1222D Texture Placement 123-1243D Texture Placement 125-126Reflections 127-128Bumps and Displacements 129-130File Textures 131-132Creating Texture Effects 133-134

Digital Cinematography 136

How Lights Work 137-138Light Effects 139-140Casting Shadows 141-142Depth Map Shadows 143-144Lighting Setups 145-146Scenery Lighting 147-148How Cameras Work 149-150Camera Moves 151-152

Rendering 154

Render Scenes 155-156Tessellation 157-158Artifacts and Anti-Aliasing 159-160Render Output 161-162Rendering and Optimization 163-164Rendering for Compositing 165-166

Effects 168

Adding Effects 169-170Opti-FX 171-172Particle Effects 173-174Paint Effects 175-176Brushes 177-178Tubes 179-180Brush Stroke 181-182Working with Paint Effects 183-184

Interactive 3D 186

Interactive 3D 187-188Game Creation 189-190Polygon Display Options 191-192Modeling for Games 193-194Primitive-up Modeling 195-196Game Specifics 197-198Building Levels 199-200

Production Notes 202

Bingo 203-204Star Wars: Episode I 205-206The Buddy System 207-208Final Fantasy and Vagrant Story 209-210Stuart Little 211-212Trophomotion 213-214Vampire: The Masquerade 215-216

Index 218

Index 219-224

Documents

the art of mayaart.ncc.edu/faculty/gorman_jason/courses/art138/... · Welcome to The Art of Maya - Personal Learning Edition. This virtual book will help guide you through the fundamental