Game Development Reference
In-Depth Information
The basic building unit of a 3D game is the vertex (or vertices for plural). A
vertex
is
a single point in virtual 3D space. It has no dimension in virtual space; it is just a
single point. It is in reality a location. To even begin to calculate a 3D object, the
computer has to start with a location. From that location, the computer then can
define other locations or vertices that define a 3D object.
Polygons
are flat planes in virtual 3D space. Vertices make up the corners of a poly-
gon plane. The lines that connect the vertices to make up the polygon plane are
called
edges
. Figure 1.10 shows several polygons, vertices, and edges.
Because a polygon is a flat plane, it has no real thickness. It is simply a plane that
indicates the joining of three, four, or many vertices. It is important to understand
that polygons don't have any depth because polygons models are almost always
hollow wire frames.
Wire frame
is the term used to describe a 3D model without
surfaces. The wire frame consists of vertices connected by edges forming polygons.
By arranging the polygons so they all connect to each other, the game artist can
create what appears to be a 3D object. Figure 1.11 shows a simple human head cre-
ated in polygons.
Polygon
Edges
Vertices
Figure 1.10
Polygons are flat planes in virtual 3D space.
