Datasheet
Exploring a 3D Scene 5
A simple triangle represents the polygon at its most basic level. ree points (with three
edges connecting them) creates a dened surface. For the most part, four-sided polygons,
also known as quads, will be the basis for your models. e reason for this will become
clear when modeling is discussed in the coming chapters, but suce it to say that many
forms can be more easily dened by quads than by triangles. By combining and blending
together multiple polygons, objects take form.
Single-Sided polygonS
Polygons exist as two-dimensional elements within the three dimensions of a scene. The flat
surfaces of polygons face in a single direction. Just as the points are infinitesimally small, so
polygons are infinitely thin. This means that they are invisible when viewed from the back.
Some thickness must be added in order to make the geometry appear from all angles.
Materials and Textures
After polygons are created, they must be assigned surface attributes to define their
appearance. A material contains the basic description of how light interacts with a sur-
face. e key components of a material are color, reection, transparency, refraction,
absorption, and emission of light. A material creates these attributes at a very basic
level that is dened by either a color or a percentage (depending on the attribute). Proper
combination of these properties can create a wide variety of looks and styles. To achieve
something beyond the evenly distributed appearance of a basic material, additional layers
must be added.
Textures add additional detail to surfaces. Textures are made from either rasterized 2D
images or mathematical functions that display colors based on various inputs. Images can
be placed on the surface of 3D models and oer a high degree of customization. You can
place details exactly where you want them and edit them either by using an application such
as Photoshop or by using texture painting inside of modo. e downside of image textures
is that they can become pixilated if they are not of a high-enough resolution. Mathematical
textures (known as procedural textures) are free from resolution and have a fairly wide
range of styles, from simple grids and gradients to complex fractal algorithms. ese tex-
tures, however, cannot be edited directly, so placement of detail is random.
ese textures can be used to modulate any aspect of a material. Color can be applied
to add variation as well as to colorize reections or transparent tints. Other possibilities
include changing the amount of reection or transparency, the shininess, the translu-
cency, or even adding the appearance of depth on a surface (see Figure1.3).
004210c01.indd 5 6/22/11 1:15 PM