Graphics Reference
In-Depth Information
Displacement Maps
Many textures use displacement maps instead of bump maps to add roughness to the surface of the model.
When applied to polygonal surfaces, seams in the geometry or UV can cause serious distortion when a dis-
placement map is applied. Figure 10-21 shows two meshes with displacement materials; the polygonal one
is broken by the displacement, but the one in SubDs (PSubs actually) holds its form and the displacement
much easier.
Figure 10-21: The polygonal mesh (left) is badly damaged by a displacement texture, while the subdivided
mesh (right) holds the added detail without problems.
The key to creating geometry that is prepped for adding deep displacements is rounding the corners.
Softer corners create base geometry that the displacement can follow, and as a result, the shift in surfaces
does not tear the polygons apart. Figure 10-22 shows the same cubes without the displacement and other
material layers. This is a very exaggerated example for the displacement, so this much rounding is not al-
ways necessary. However, keep this principle in mind when creating structures that will carry displacement
maps as a part of the material. Remember, as depth of the displacement decreases, so can the roundness of
the corner of the model.
Figure 10-22: The roundness required for a deep displacement is high but decreases as the depth of the
displacement decreases.
 
 
 
 
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