The Importance of Resolution in CG - An Introduction to Computer Graphics for Artists - page 89

Fig. 7.1 A highly optimized environment model, courtesy of Stan Verbeek. Most of the detail is
represented with texture maps, not geometry

There are several ways to describe the resolution of an object. Some refer to the
object itself, others to the CG “materials” used to construct its CG replica.

7.2 Object-Based Resolution

Just as a person can be described as one unit, a “person”, or a very long list of
organs, muscles, bones, nerves, veins, arteries, and other features, CG objects may
be described as a single entity or a collection of smaller parts. The difference is
that a person always contains the many parts described above and more, but a CG
character can be one object without having any sub-parts. This is but one way to
limit the resolution of an object. The fewer pieces it has, or the fewer separately
defi ned parts there are, the simpler the object is. A statue of a human fi gure has arms,
legs, head, and torso. If the statue is static, then these parts do not need to articulate,
or move. Because it doesn't need to move, the statue may be described as a single
object without parts. This saves the artist the trouble and expense of designing and
building joints and other structures required for animation.
If a statue must move as a person would, then its polygonal resolution will rise
sharply because multiple rings of polygons must be added to every joint to ensure
they deform properly when they are articulated. The additional detail in the example
of an articulated statue is less obvious than that of an object whose parts are distinct,
such as an exposed car engine. With a human character, the majority of the detail
lies beneath the skin, invisible. With a car engine, it is as if the skin has been stripped
off and the detail beneath exposed. How should these parts be built? Is it necessary