Optimization of CG Models - An Introduction to Computer Graphics for Artists - page 107

Fig. 8.7 The blue lines in this image are edges that had to be carved into the model to accommo-
date the texture plan (Model courtesy of Chris McEntee)

Because texture maps represent structural detail, they must be considered at the
planning stage of a model. It is for this reason that modelers who do not understand
the work of the texture artist tend to build more than is necessary at the same time
as the model contains fewer texture boundaries than are desired by the texture artist.
Any artist who would learn to be a professional modeler should make a point of
learning to texture models also, to better understand how the two disciplines affect
each other.

8.12 Opacity Maps

If you cannot spare the polygons to create a complex shape, consider using an opac-
ity map (also known as a transparency map) to describe the information. An opacity
map uses a grayscale image to defi ne opaque, transparent, and semi-transparent
areas on a polygon. These might be used to represent a distant wrought iron fence
in the background, because it is too far away to see that the fl at polygon the opacity
map is attached to has no thickness.

8.13 Silhouette

You can use the silhouette of your model to gauge whether you have taken too much
from it (Fig. 8.8 ). Depending on how your object will be used, you may be able to
reduce the number of triangles to the minimum required to retain its silhouette in
most angles. This can drastically reduce your triangle count.