Creating Thick and Thin Glass and Plastic

Another feature of the mia_material shader is the ability to simulate thickness and thinness in the material itself without
creating extra geometry. This can be very useful, especially for glass surfaces.
1. Continue with the scene from the previous section, or open the helmet_v06.ma file from the chapter10
\scenes folder at the book’s web page.
2. In the Hypershade, create two new mia_material_x nodes. Name one thinGlass and the other thickGlass.
3. Apply the thinGlass shader to the glassShield object in the Outliner.
4. Apply the thickGlass material to the lampShields group in the Outliner.
5. In the Attribute Editor for the thinGlass material, use the Preset button to apply the glassThin preset.
6. In the Attribute Editor for the thickGlass shader, apply the glassThick preset.
7. Create another test render from the renderCam camera.
The lamps at the top of the helmet have a chrome reflector behind the thick glass, which adds to the reflectivity of the
material. The settings to control thickness are found under the Advanced Refractions controls. Along with the standard Index
Of Refraction setting, there is an option for making the material either thin-walled or solid. You also have the option of
choosing between a transparent shadow and a refractive caustic that is built into the material (the caustics render when caustic
photons are enabled and the light source emits caustic photons; for more information on caustics, consult Chapter 9).
1. Open the Hypershade window, and create another mia_material_x node. Name this one plastic. Apply this shader to
the plasticParts group in the Outliner.
2. Open the Attribute Editor for the plastic shader, and apply the translucentPlasticFilmLightBlur preset.
3. Create another test render.
This preset creates very translucent plastic using glossy refractions. In this situation, it seems a little too transparent. Use
the following settings to make the plastic look more substantial:
a. In the Diffuse section, set Color to a dim pale blue.
b. In the Reflection section, set Color to a dark gray, and set Glossiness to 0.35.
c. In the Refraction section, set Color to a dark blue and Glossiness to 0.52.
d. Scroll down to the Ambient Occlusion section, and activate Ambient Occlusion.
e. Set Ambient Light Color to a light gray.