Architectural_Design_with_SketchUp

Architectural Design with SketchUp
As you can see, the model is well lit with shadows that are not too dark. However, two
problems are apparent.
First, the two rear lights are too bright. Their proximity to the background creates two
overly bright areas. You might be tempted to think that what you see there are the actual
lights. After all, if we take a photograph of a lightbulb, we get a similar result—a very overexposed
area around the lightbulb. That is not the case here. None of the standard lights that
we use in rendering (omni lights, spotlights, IES lights) show up on renderings because they
have no physical representation; they are merely computational light sources.
The second problem is that the front of the person is too much in the shade. Although
this gives the scene a dramatic look, such an effect might not be intended.
Let’s start by fixing the first problem. Figure 5.45 shows a modified version of the same
setup, in which light intensity of the background lights has been reduced drastically (to about
1/10 the intensity of the front light). These lights also received a blue light color to give the
background more depth and interest.
Figure 5.45: Modified setup (reduced light intensity and added light color)
We can now go a step further and add one more omni light—this time, directly in front of
the person (see Figure 5.46). This light functions similar to a flash that would be mounted on
the observer’s camera and is needed solely to brighten the shadows on the model. Because
such a light would create a shadow on the background, shadows were disabled for this light.
Ideally a “stage” setup like this should have omni lights for the background and a spotlight
for highlighting the person in the foreground. We discuss spotlights in a later section.
First, however, let’s look at an important light property: attenuation.
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