Datasheet

Physics
You’ll see in Chapter 12 that one of Maya’s most powerful features is its ability to simulate
the dynamics of moving objects. To use that capability effectively, you need a general
awareness of the properties of physics—how objects behave in the physical world.
NEWTON’S LAWS OF MOTION
There are three basic laws of motion. Sir Isaac Newton set forth these three laws, summa-
rized here:
• An object in motion will remain in motion, and an object at rest will remain at rest
unless an external force acts upon the object. This is called inertia, and understanding
it is critical to good animation. You’ll find more on this in Chapters 8 and 9.
• 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 back to your hand. That way your
hand doesn’t smash through the wall.
Everyone in animation should and will definitely come to understand the first two laws to
a good degree since they play a large part in how your animations should look.
MOMENTUM
In particular, it’s important to understand what momentum is all about. When an object is
in motion, it has momentum. The amount of momentum is calculated by multiplying the
mass of the object by its velocity. The heavier something is, or the faster it is moving, the
more momentum it has and the bigger the bruise it will leave if it hits you.
That’s why a tiny bullet can cause such a great impact on a piece of wood, for example.
Its sheer speed greatly increases its momentum. Likewise, a slow-moving garbage truck
can bash your car, relying on its sheer mass for its tremendous momentum.
Basically, when one moving object meets another object that is moving or not,
momentum is transferred between them. That means when something hits an object, that
target is somehow moved if there is sufficient momentum transferred to it. For more on
this notion, see the axe-throwing exercise in Chapter 8.
Summary
In this chapter, you learned the basic process of working in CG, called a work flow or
pipeline, which is similar to the process of working on a typical production. In addition,
this chapter covered the core concepts of CG creation and the fundamentals of digital
images. Some important ideas in design foundation as well as traditional animation
concepts were also covered.
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