Architectural_Design_with_SketchUp

Chapter 5 Rendering in SketchUp
Reflection
When you render a SketchUp scene in your rendering software using default settings, you
may notice that all materials look quite flat. They look very much like matte paint. In reality,
however, most materials have some degree of shininess and maybe even reflectivity. Good
examples are semigloss wall paint, the plastic or aluminum enclosure of your computer,
magazine covers, and tabletops. Although their degree of shininess varies, most of them do
have some. Only very rough materials (e.g., uncoated paper or soil) do not. (See Figure 5.68.)
Figure 5.68: Reflectivity of a walkway’s stones
As you likely know, this is related to surface smoothness—the smoother the surface, the
shinier a material is (up to perfect reflection). Polished metal and glass are materials that are
very reflective—a mirror is a good example. Brushed aluminum (with its roughened surface) is
quite reflective, but its surface scatters all light, thereby lacking a shiny and polished-looking
reflection.
Figure 5.69 shows two materials that illustrate this. The ground material on the left has
default properties and therefore looks quite flat. The material on the right has reflectivity
similar to polished stone. As you can see, the reflection of the omni light (in the center of the
image) is quite different from that of the material on the left. The light’s reflection is visible
on the ground, and there is not as much scattered light reflection close to the light source.
Also, the checkered pattern on the back wall is reflected in a realistic fashion: Close to the
wall, where the view angle is quite small, the pattern has a blurry reflection. Farther away
from the wall and closer to the viewer (where the viewing angle is larger), the reflection fades
out. This material appearance is typical of vinyl flooring or a semigloss tabletop, for example.
So what should you do to materials in your renderings? It is usually a good idea to give
flooring, furniture, leather, and other partially or fully reflective materials at least a subtle reflectivity.
This goes a long way toward realism in your renderings. Having said that, it is important
to keep in mind that reflectivity invariably increases rendering time. Only perfect reflection
renders fast, but that is obviously limited to mirrors and water or glass. Therefore, whenever
a material is too far away from the viewpoint or nothing exists in the scene that could actually
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