Observation Skills and CG - An Introduction to Computer Graphics for Artists - page 42

This category of observation is called a substitution error because the artist is
substituting what they think is right in place of what they have observed.

3.2.5 Knowledge

Models of characters usually contain observation errors if they are made by artists
with little absolute knowledge of anatomy. This is noticeable in two ways: propor-
tions and connections. Parts that are given an inordinate amount of attention (myo-
pic focus) tend to be enlarged, such as facial features, shoulders, hands and breasts.
Anatomical structures of lesser interest, like the back of the head, the abdomen in
women, or feet, tend to be smaller than they should be.
The function of muscles is to articulate the skeleton, whose parts are connected
by ligaments. Each muscle has an origin on one bone and an insertion on another (or
in the skin of the face.) The location of these origins and insertions are specifi c to
the function of the muscles. This means that the superfi cial lumps we see under the
skin are all based on the exact location and orientation of muscles relative to their
attachment points. Artists who are unaware of this have a tendency to ignore the
connections as well as the function of the muscles. By doing this, they either add to
or subtract from the correct number of muscles at the same time as the subcutaneous
structure of the muscles themselves wanders beyond believable boundaries.
Just as lack of anatomical knowledge makes it more diffi cult to analyze a character,
lack of other types of knowledge can interfere with an artist's observational skills. This
is one of the reasons many artists develop specialties, such as characters, vehicles, or
architecture. By carefully studying the subject, their observation skills are enhanced.

3.2.6 Holistic

The holistic observation type is what artists should strive to achieve. With this level
of observation skill, the artist will see an object as a whole, and understand how all
of its parts contribute to it, and in exactly what proportion. The artist will not sup-
press their observations in favor of a notion of what something should look like, nor
will they schematize a subject. They will trust and control their observations to yield
a complete and consistent understanding of the target object.

3.3 Special Problems

3.3.1 Intrinsic Color

Color is a property of light, not of the objects we see around us (Reinhard et al.
2009 ). Despite this, different materials consistently refl ect light in the same way.
This makes it possible to identify specifi c fi xed colors as belonging to individual