Meshes and Materials

For a computer to visually represent a 3D object, it needs two things: a 3D mesh and a material.

Meshes

3D meshes allow you to specify the size and shape of an object, like this mesh representing a monkey's head:

Figure 1.45: A 3D mesh of a monkey's head

Meshes are comprised of several vertices, edges, and faces. Vertices are simply a 3D coordinate with an X, Y, and Z position; an edge is a connection (that is, a line) between two vertices; and a face is a connection of three or more edges. You can see in the previous figure the individual vertices, edges, and faces of the mesh, where each face is colored between white and black, depending on how much light is reflecting off the face. Nowadays, video games can render meshes with thousands of vertices in such a way that you can't tell the individual vertices apart because there are so many of them so close together.

Materials

Materials, on the other hand, allow...