Architectural_Design_with_SketchUp

Chapter 5 Rendering in SketchUp
surface of the material but then scatter it internally. The thicker the material, the less light
travels through it. Good examples of these kinds of materials are wax, milk, alabaster stone,
and translucent rubber.
To render these materials accurately, your rendering software must be able to handle a
material feature called subsurface scattering (SSS). This material feature can then be assigned
to any closed object (an object that has a volume and no openings in its surface). You can see
the effect in Figure 5.76, where the candle wax material has subsurface scattering properties.
As you can see, it is a white reflective material that internally also scatters some of the flame
light, which was modeled as a combination of an omni light and a light-emitting flame object.
Figure 5.76: Three candles with subsurface-scattering wax materials
Using SSS for materials in your scene can put a strain on rendering time, and you should
carefully evaluate whether you actually need it. For example, if you render a kitchen that
has a few candles standing in a corner, you will likely get away with applying a simple white
material (maybe with some glossiness) to the candles. However, if you render a close-up of
a milk glass lit only by candles, you should use it for those two materials.
When you model translucent materials (as in the lampshade shown next), you have several
options:
NN
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Use an SSS material—This requires your lampshade to have an actual thickness and
will likely result in a relatively long rendering time. Use the Joint Push/Pull plugin (see
Chapter 4) to thicken the surface.
Use a partially transparent material—This may work, especially if light can bounce
inside the lampshade.
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