Lighting - 3D for Graphic Designers - page 92

In the example shown in Figure 4-12 , Environment Material is set to Constant, with Zenith Color set to
black, and Luminous Intensity on the sphere material is increased to 1.0. The resulting image is lit entirely
by geometry and the luminous texture. With a little bit of adjusting, the sphere can appear to be a lightbulb
illuminating the scene.
Figure 4-12: A simple luminous material on the sphere causes it to light the scene.
In Figure 4-13 , a gradient was added to the luminous amount that allowed it to fall off gently toward the
edges of the sphere, and some reflections were added to give it a glassy finish. In many cases, lighting with
this type of global illumination will produce more-polished results in less time. For instance, each of the
renderers with the glowing spheres took less than 20 seconds to complete.
Figure 4-13: With some adjustments, the sphere is turned into a glass lightbulb for added realism.