ZBrush Character Creation - Advanced Digital Sculpting 2nd Edition

328 chapter 9 ■ Normal Maps, Displacement Maps, Maya, and Decimation Master

In this section, we explored the two major

displacement map types that can be exported from

ZBrush, and you learned how to set up models and

shaders for displacement in Maya. By combining

your texture map, displacement, diffuse, and bump

maps with a subsurface scattering shader, you can

achieve renders like the one shown in Figure 9.51.

The ability to capture the high detail of your char-

acters in other renderers allows you to take your

work to the next level, breathing life and animation

into your work. In the next section, we’ll continue

looking at difference maps in ZBrush by discussing

Normal Maps

Normal Maps

Normal maps are color maps that represent the surface

normal direction of any given point on the model. They

allow a renderer to create the impression of a highly

detailed surface on a low-polygon base. Figure 9.52

shows an example of a normal map and the rendered

result on a model.

Normal mapping differs from displacement in

one major way. While displacement mapping makes

actual geometry at render time by subdividing the

mesh, normal mapping creates the illusion of a highly

detailed surface without changing the geometry. The

benefit of this is speed, but the drawback is that the

silhouette of the model will not change. In Figure 9.53,

the character on the right is displaced while the char-

acter on the left is normal mapped. Note how the pro-

files are still angular on the normal mapped figure.

For this reason it is imperative that the base

model be optimized to best represent the overall pro-

files of the model when you will be normal mapping.

If your low-polygon mesh is too low and does not

represent the form of the high-res, you will end up

with errors in your normal map at worst—or at least

a normal map that is unconvincing when displayed

on a faceted model.

Normal maps offer a superb way to create the

illusion of a highly detailed surface on a low-polygon

base. Normal maps are actually generated from bump

maps when processing; this process is invisible to the

user but understanding it will help you understand

the inner workings of the normal map.

Figure 9.50 Mesh artifacts in render

Figure 9.51 The Stingerhead character rendered with dis-
placement and subsurface scattering