Basic Game Art Concepts - Game Character Creation with Blender and Unity - page 10

Now let's add a third axis, the z-axis. If shapes on the xy coordinate plane can be said
to be two-dimensional, objects on the xyz plane are three-dimensional. Points and lines
have three-part coordinates consisting of their location in relation to the x-, y-, and z-axes
(Figure 1.11). Also, like their 2D counterparts, polygons exist in 3D along these axes and
can be combined to create 3D forms such as cones, cubes, spheres, and many others, as
shown in Figure 1.12.

z-axis z-axis

(-4,-3,9) (-4,-3,9)

(3,4,4) (3,4,4)

(3,2,3)

x-axis

x-axis

y-axis y-axis

Figure 1.12
The xyz coordinate plane with a polygon

Figure 1.11
The xyz coordinate plane with a line

These types of objects and measurement systems are the basis of what we know as 3D
computer graphics, also known as computer-generated imagery (CGI). When you work
with objects in 3D modeling programs like Blender, you manipulate the points, lines, and
polygons of an object to create complex forms.
In the computer graphics industry, the points of a model are called vertices ( vertex in
the singular). The lines between vertices are called edges . The three-dimensional forms
that are created when at least three vertices are connected by edges are called polygons . If
a polygon has a surface on it, this is called a face . Figure 1.13 illustrates these concepts.
When polygons or faces are arranged in such a way that they create a three-dimensional
form, this is called a mesh . Some meshes of basic 3D forms are so widely used that
they come premade in 3D programs. These are called
primitives . The objects in Figure 1.14 are some of the basic
mesh forms available in Blender. Many are primitive
objects, though there are some more complex ones like
Suzanne the Monkey.

Figure 1.13
Illustration of ver-
tex, edge, polygon,
and face

polygon
with face

edge

vertex