Chapter 1 AL Introduction to Computer Graphics and 3D RI This book will introduce you to the workings of 3D animation CO PY RI GH TE D MA TE (called computer graphics, or CG) with one of the most popular programs on the market, Autodesk Maya. It will introduce you to many of Maya’s features and capabilities with the intent of energizing you to study further. Having said that, let’s face a basic fact: The best way to succeed at almost anything is to practice.
■ Chapter 1: Introduction to Computer Graphics and 3D Art? Art, in many instances, requires transcendence of its medium; it speaks of its own accord. Art goes beyond the mechanics of how you create it (whether by brush or mouse) and takes on its own life. Learning to look beyond what you’re working with and seeing what you’re working for is the key to creating art with CG. Try not to view this experience as learning a software package, but as learning a way of working to an end.
Computer Graphics If you’re familiar with 2D graphics software, such as Adobe Illustrator or Adobe Flash, you already know something about vectors. Maya and other 3D graphics tools add the calculation of depth. Instead of drawing objects on a flat plane, they’re defined in three-dimensional space. This makes the artist’s job fairly cerebral and very different than it is for 2D art; in 3D art, there is more of a dialogue between the left and right sides of the brain.
■ Chapter 1: Introduction to Computer Graphics and 3D image editors. The CG workflow is based on building, arrangements, and relationships. But it’s an easy workflow to pick up and master in time. It can be learned by anyone with the desire and the patience to give it a try. Animation Animation is change over time. In other words, animation is the simulation of an object changing over a period of time, whether it’s that object’s position or size, or even color or shape.
The Stages of Production ■ 5 entering into production without a good plan of attack will not only cause trouble, but also stunt the growth of your project. In the real world, preproduction is part of every CG animation project. For the tutorial projects in this book, the sketches and other files supplied on the book’s web page are your preproduction; however, try to gather as much information as you can about the objects you’ll create beyond what is presented.
■ Chapter 1: Introduction to Computer Graphics and 3D The Conceptual Art Conceptuals are the design elements that you may need for the CG production. Typically, characters are drawn into character sheets in three different neutral poses: from the front, from the side, and from an angle called a ¾ view. You can also create color art for the various sets, props, and characters to better visualize the colors, textures, and lighting that will be needed.
The Stages of Production We’ll take a quick look at three more postproduction activities: compositing, editing, and adding sound. These are advanced topics, and complete coverage is beyond the scope of Introducing Autodesk Maya 2012. However, a multitude of books are available on these topics for further study, and some are listed at the end of this chapter. Compositing Quite often, CG is rendered in different layers and segments, which need to be put back together.
■ Chapter 1: Introduction to Computer Graphics and 3D Sound Sound design is critical to CG because viewers associate visuals with audio. A basic soundtrack can give a significant punch to a simple animation by helping to provide realism, mood, narrative, and so on, adding a greater impact to the CG. Sound effects, such as footsteps, are inserted to match the action on the screen. This type of sound is also known in film as Foley sound. Music is scored and added to match the film.
The CG Production Workflow Modeling Modeling, the topic of Chapters 4 through 6, is usually the first step in creating CG. It’s the topic that garners a lot of coverage in publications and captures the interest of most budding CG artists. Downloading or purchasing models from the Internet can often cut down the amount of time you spend on your project. This, of course, assumes you’re not a fan of modeling and prefer to spend your time animating or working on texturing and lighting.
■ Chapter 1: Introduction to Computer Graphics and 3D Figure 1.2 Texturing adds detail to an otherwise flat model. Animation You can make or break your scene with animation. We all have an innate sense of how things are supposed to move on a visceral level, if not an academic one. We understand how physics applies to objects and how people and animals move around. Because of this, viewers tend to be critical of CG’s motion if it’s not lifelike.
Core Concepts The type and number of lights you use in a scene greatly affect not just the look of your scene, but also the amount of time the scene takes to render. Lighting becomes a careful dance between pragmatics and results. It’s perhaps the subtlest part of CG to master. When you gain more experience with lighting, you’ll notice that it affects every part of your CG creation. Before long, you’ll start modeling differently—that is, modeling with the final lighting of the scene in mind.
■ Chapter 1: Introduction to Computer Graphics and 3D Raster Images Figure 1.3 Raster images (a.k.a. bitmapped images) make up the world of computer images today. A raster or bitmap image is a mosaic of pixels; an arrangement of colored pixels onscreen or dots on a print to display an image. Everything you create in Maya will eventually be seen as a raster image, even though you first create it using vectors.
Core Concepts SolidWorks. These programs let you define shapes and volumes and add color and texture to them through their toolsets. They store the results in scene files containing coordinates and equations of points in space and the color values that have been assigned to them. This vector information is then converted into raster images (called rasterization) through rendering so you can view the final image or animation.
■ Chapter 1: Introduction to Computer Graphics and 3D Color D epth An image file stores the color of each pixel as three values representing red, green, and blue. Image type depends on how much storage is allotted to each pixel (the color depth). These are the color depths common to image files in CG production: Grayscale The image is black and white with varying degrees of gray in between, typically 256 shades of gray.
Core Concepts Each channel is a measurement of how much red, green, or blue is in areas of the image. A fourth channel, called the alpha channel, is used as a transparency channel. This channel, also known as the matte channel, defines which portions of the image are transparent or opaque. Not all image files have alpha channels. You can read more about alpha channels in Chapter 7. File Formats In addition to image types, several image file formats are available today.
■ Chapter 1: Introduction to Computer Graphics and 3D Color Color is how we perceive the differences in the wavelengths of light. The wide range of colors that we see (the visible spectrum) results when any of three primary colors of light—red, green, and blue—are “mixed” together. You can mix color in two ways: subtractive and additive.
Core Concepts 256 possible levels. With three channels, you have 256 × 256 × 256 (16.7 million) possible combinations of each primary color mixed to form the final color. Color value can also be set on the hue, saturation, and value (HSV) channels. Again, each channel holds a value from 0 to 255 (in an 8-bit image file); these values combine to define the final color. The hue value defines the actual tint (from red to green to violet) of the color.
■ Chapter 1: Introduction to Computer Graphics and 3D You’ll adjust your final render size to suit the final medium for which you’re creating the animation. Table 1.1 lists some standard resolutions. Table 1.
Core Concepts The number of frames played back per second determines the frame rate of the animation. This is denoted as fps, or frames per second. The following are the three standard frame rates for media: • NTSC: 30fps • PAL: 25fps • Film: 24fps Knowing your output medium is important when beginning an animation project. Although it isn’t crucial, it can affect how you design your framing, create your movements, render your project, and so on.
■ Chapter 1: Introduction to Computer Graphics and 3D Figure 1.5 Solar System with the Sun placed at the origin, the planets orbiting the World axis and rotating on their own Local axes, and moons orbiting the planets and also rotating (see Figure 1.5). The Sun at the origin, Earth and other planets orbiting the World axis while rotating on their own axes, and the Moon orbiting Earth Basic Design Concepts Composition is all about how you lay out your scene and design your colors.
Core Concepts In the design lexicon, form means anything you can see; it has some sort of shape, color, or texture that distinguishes it from its frame. How your scene’s objects lie in the frame defines your composition. The space behind and between what is rendered out is the ground, or background plane. Objects become positive space, and the background becomes negative space. Playing with the position of positive and negative space greatly affects the dynamics of your frame.
■ Chapter 1: Introduction to Computer Graphics and 3D Contrast Figure 1.7 Contrast in design describes how much your foreground subject “pops” from the background. As you can see in Figure 1.7, when you create an area in your frame that contains little variation in color and light, the image seems flat and uneventful. Using dark shadows and light highlights increases the perceived depth in the image and helps pop out the subject from the background.
Basic Film Concepts Basic Film Concepts In addition to the design concepts used in framing a shot, you’ll want to understand some fundamental filmmaking concepts. There’s nothing more important than having a solid, manageable, and achievable plan for your conceptual goal. Almost everybody in production lays out this plan in advance of the principle photography. You can’t run into the street with someone else’s expensive camera and not know what you’re going to shoot. CG takes time.
■ Chapter 1: Introduction to Computer Graphics and 3D Lighting Although CG lighting techniques may seem completely different from lighting in real life, the desired results are quite often the same. The more you understand how real lights affect your subjects in photography, the better you’ll be at CG lighting. How you light your scene affects the contrast of the frame as well as the color balance and overall design impact.
Basic Film Concepts ■ 25 Figure 1.8 Keyframe at frame 1 Frame 5 Frame 10 Frame 15 Frame 20 Frame 25 Keyframe at frame 30 Weight in animation is a perception of mass. An object’s movement, how it reacts in motion, and how it reacts to other objects together convey the feeling of weight. Otherwise, the animation will look bogus—or, as they say, “cartoonish.” Weight can be created with a variety of techniques developed by traditional animators over the years.
■ Chapter 1: Introduction to Computer Graphics and 3D S q uash a n d S tretch This technique makes a character, for example, respond to gravity, movement, and inertia by literally squashing it down and stretching it up when it moves. For example, a cartoon character will squeeze down when it’s about to jump up, stretch out a bit while it’s flying in the air, and squash back down when it lands to make the character look as if it’s reacting to gravity.
Basic Film Concepts • The more massive an object is, the more force is needed to accelerate or decelerate its motion. This law deals with an object’s momentum. • Every action has an equal and opposite reaction. When you press on a brick wall, for example, the wall exerts an equal amount of force on your hand. That way, your hand doesn’t smash through the wall. Momentum It’s important to understand what momentum is all about. When an object is in motion, it has momentum.
■ Chapter 1: Introduction to Computer Graphics and 3D continued Kerlow, Isaac. The Art of 3D Computer Animation and Effects. New York: John Wiley & Sons, 2009. Kuperberg, Marcia. Guide to Computer Animation. Burlington, MA: Focal Press, 2002. Masson, Terrence. CG 101: A Computer Graphics Industry Reference. Williamstown, MA: Digital Fauxtography, 2007. Pe r i o d i ca l s Computer Graphics World (free subscription for those who qualify) www.cgw.com Cinefex www.cinefex.com HDRI 3D www.hdri3D.
Summary Now that you have a foundation in CG and 3D terminology and core concepts, you’re ready to tackle the software. Maya is a capable, intricate program. The more you understand how you work artistically, the better use you’ll make of this exceptional tool. There is a lot to think about before putting objects into a scene and rendering them. With practice and some design tinkering, though, all this will become intuitive.
