Architectural_Design_with_SketchUp

Chapter 5 Rendering in SketchUp
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Typical settings for a physical sky system are:
Turbidity—The amount of haziness is set by this value. This affects brightness as well as
light color based on the underlying algorithm.
Sun intensity and color—Modify these to fine-tune the settings beyond what is built
into the physical sky calculation.
Figure 5.29 shows the effect of varying the turbidity/haziness parameter.
Another option that may be appropriate for some renderings (especially studio-type setups)
is to not have a sky at all and instead select a color (gray, for example) to provide the
rendering with a uniform background. Figure 5.30 illustrates this approach.
A third option is to have a full-screen image aligned behind the scene. Typically, this is
possible within the rendering software by simply selecting an image from your hard disk. A
drawback of this approach is that you must take care to match sun angles and light mood
between the background image and the rendered scene before you use the image. Depending
on the rendering software, these images also may not appear in reflections. Furthermore,
this approach is not useful for animations where the camera or the sun is animated. A benefit,
however, is that you can easily take a photograph of the environment of, for example, a
new building from exactly the position where a window will be and then use that image as
a realistic-looking backdrop for an interior rendering. (See Figure 5.31.)
A side benefit of using this approach is that later you can easily remove the sky (and replace
it with a photograph) in Photoshop or any other graphics software by selecting and erasing
the background color. This is especially true if you “green screen” the back with a bright green
color (0,255,0 in RGB values).
Figure 5.28: Physical sky (top: late morning light; bottom: sunset
light)—the sky color is based on the time of day
Figure 5.29: Two renderings of the same scene at the same time
(top: low turbidity; bottom: high turbidity)
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