Introduction to Displacement
Displacement maps are grayscale textures applied to the mesh that
push and pull the vertices according to the image’s grayscale value.
Displacement usually requires a high-resolution mesh for a finer
level of detail because it deforms the mesh (unlike bump maps that
only create the illusion of surface relief). An object with displace-
ment can be at a low resolution in the viewport (for speed and
real-time rendering issues) and at a ultra-high resolution at render
time.
In Figure 10-31, the image at left shows how the procedural dis-
placement map is applied on the plane. The image on the right
shows how this information deforms the mesh.
Figure 10-32 shows another displacement example. The checker-
board mapping, in pure black and white, produces very sharp results
when the resolution of the mesh allows it.
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Figure 10-31
Figure 10-32
The displacement resolution is pretty much related to the density of
the mesh. The image on the left in Figure 10-33 has many more
polygons than the image on the right. We can see the difference
when comparing the displacement of both meshes.
Figures 10-34 to 10-36 show the displacement map used at the left
and the effect produced in the shape at the right. Notice that the
white and gray areas push up the vertices and the black area pushes
down.
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Figure 10-33
Figure 10-34
In the following example, notice the difference in the displacement
when we change the blur of the map.
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Figure 10-35
Figure 10-36
Figure 10-37 shows a sharp 2D shape to be projected as a displace-
ment map. Notice the hard edges and crisp polygons.
Now we add some smoothing using Gaussian blur on the above fig-
ure, which produces a much smoother result during displacement.
Note that displacement can be applied to any piece of geometry.
However, to make it work properly it is recommended that the UV
mapping be very accurate to ensure the correct mapping informa-
tion will match the displacement.
Figure 10-39 shows a sphere with fractal noise displacement
and a cylinder mapped with checkerboard displacement.
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Figure 10-37
Figure 10-38
Displacement can be very useful for increasing the amount of detail
in the geometry that otherwise would be difficult or impossible to
create. But while displacement can be very handy, it’s a nonintuitive
way to achieve results because there isn’t any real-time feedback.
Because you can’t see the mesh being deformed by the brush, it is
almost impossible to achieve good results in organic forms. It’s pos-
sible to paint the grayscale displacement maps with any 2D painting
program, but the result may not be what the user was aiming for.
In the next chapter we discuss the benefits of using ZBrush, a
software package that allows us to paint the displacement map and
simultaneously see the results that the painting is actually produc-
ing on the piece of geometry we are working on. This lets us create
the displacement map using one of the most artistic and intuitive
ways possible today.
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