Advanced Light and Materials Properties and Effects ◾ 379
Figure15.13 shows the scene without
Global Illumination and Final Gathering.
Notice the area around the brass bolt.
Look at the same area in Figure 15.14,
rendered with Global Illumination and
Final Gathering.
CAUSTICS
Caustics are used to create the harsh light
reections and refractions we oen get
when light hits a glass object. We will
manipulate both the lights in a scene and
the mental ray settings to create Caustics.
We have a NURBS curve that has been
revolved to make a dish. A mental ray
mia_material with a Glassin preset
has been created (see Figure 15.15) and
applied to the dish (see Figure 15.16).
e scene without Caustics is shown
in Figure15.17. Figure15.18 shows turn-
ing on Caustics in the mental ray Render
Settings. In Figure15.19, we turn on pho-
ton emitting in the attributes of the dom-
inant light in the scene, which happens to
be a spotlight with a wide cone. e other
light in the scene is also a spotlight with a
wide cone, but its intensity is much lower.
We render the scene again, and the result is shown in Figure15.20.
LIGHT EMITTING MATERIALS: IRRADIANCE
First, we choose a highly reective material from the mental ray list of materials (see
Figure15.21). We apply this material to the dish, as seen in Figure15.22.
Now, we turn down the Intensity attributes of our two spotlights and render. e result
is shown in Figure15.23. ere is very little light in the scene. Now, we turn up the irradi-
ance of the material, as shown in Figure15.24. e result can be seen in Figure15.25. We
have an otherworldly goblet.
COLORING MENTAL RAY’S GLASS MATERIAL
One way to color a surface with a transparent material on it is by adding color to the light
that refracts through that material. First, we go to:
any Main menu → Window → Rendering Editors → Hypershade
FIGURE 15.13 Render without GI and FG.
FIGURE 15.14 Render with GI and FG.