Architectural_Design_with_SketchUp

Chapter 5 Rendering in SketchUp
The first method is general illumination caused by a uniformly colored light that is emitted
from an imaginary sky dome (a sphere that fully encompasses your model). Typically, you can
simply select a sky color and then use any rendering method provided with your software.
Because the result will look very much like an ambient occlusion (AO) rendering, that rendering
method can give sufficient results. See Figure 5.38 for an example.
Figure 5.38: Ambient occlusion “clay” rendering of Notre Dame
This method is often used for “clay” renderings (like the one in Figure 5.38) where the
material has been painted with either the default material or a neutral-color material (such as
light gray). Often, this is not even necessary—the rendering software simply ignores all textures
during rendering if Clay Render is selected. A benefit of this rendering method is that
it allows you to evaluate shapes without being distracted by color and other surface textures.
A second method—which works well for clay renderings but especially for textured models—is
image-based lighting (IBL). In this method, an image is applied to the imaginary “sky
dome” similar to what was described in the “Environments” section. If this image contains
a spherical projection of the sky and ground, it can be used to represent a full 360-degree
background. Even if the image will not be visible in the final rendering, its color information
will be used to apply environmental lighting to the rendered scene. The three images in
Figure 5.39 are examples of IBL with a high-dynamic-range (HDR) image as a light source.
Note the different shadows and overall light mood and color.
This method is especially powerful when HDR images are used for the environment map.
Because an HDR image stores color information at a much higher level of precision (32 bits)
than a standard low-dynamic-range (LDR) image (e.g., 8 bits for a standard JPG image), lighting
in the HDR renderings is very natural-looking. This approach also permits reuse of a particular
interesting light setting (e.g., the environment in a church), whereby you can apply it
to a completely different scene.
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