Datasheet
24 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. If the lights in your scene are too flat or too even, they weaken
your composition and abate your scene’s impact.
You’ll learn more about Maya lighting techniques in Chapter 10.
Basic Animation Concepts
As mentioned at the beginning of this chapter, animation is the representation of change
over time. This concept is the basis for an amazing art form that has been practiced in
one way or another for quite some time. Although this section can’t cover all of them,
here are a few key terms you’ll come across numerous times on your journey into CG
animation.
Frames, Keyframes, and In-Betweens
Each drawing of an animation—or, in the case of CG, a single rendered image—is called
a frame. The term frame also refers to a unit of time in animation whose exact chrono-
logical length depends on how fast the animation will eventually play back (frame rate).
For example, at film rate (24fps), a single frame lasts 1⁄24 of a second. At NTSC video rate
(30fps), that same frame lasts 1⁄30 of a second.
Keyframes are frames in which the animator creates a pose for a character (or whatever
is being animated). In CG terms, a keyframe is a frame in which a pose, a position, or some
other such value has been saved in time. Animation is created when an object travels or
changes from one keyframe to another. You’ll see firsthand how creating poses for ani-
mation works in Chapter 9 when you create the poses for a simple walking human figure.
In CG, a keyframe can be set on almost any aspect of an object—its color, position,
size, and so on. Maya then interpolates the in-between frames between the keyframes set
by the animator. In reality, you can set several keyframes on any one frame in CG anima-
tion. Figure 1.8 illustrates a keyframe sequence in Maya.
Weight
Weight is an implied, if not critical, concept in design and animation. The weight of your
subject in the frame is a function of the way it’s colored; its contrast, shape, and location
in the frame; and the negative space around it, to name but a few ways of looking at it. In
animation, weight takes on a more important role. How you show an object’s weight in
motion greatly affects its believability. As you’ll see in the axe tutorial in Chapter 8, creat-
ing proper motion to reflect the object’s weight goes a long way toward producing believ-
able animation.
900215c01.indd 24 3/11/11 10:13:16 PM