Now that you have set the Diffuse color, you should set the Ambient color. Remember, the Ambient color is the color of our material in shadow, so it should always be darker then the Diffuse color. To do this, drag your Diffuse color swatch on top of the Ambient color swatch, and when prompted click Copy. This is an easy way to get the same color in both areas. Now all you have to do is make the Ambient color darker:

1.  Click the color swatch.

2.  Decrease the color’s Value to get a grayish shade of 150 or so.

3.  Render your scene again.

Now it’s time to give your teapot a specular highlight. Many factors will control the look and size of the highlight. It’s important to pay close attention to the sample sphere in the Material Editor; it will give you a sneak preview of your highlights. Sometimes your sample sphere may have the correct highlights, but your scene does not. That is most likely because of the lighting setup in your scene. Remember that specular highlights can be seen best on curved surfaces.

1.  Change your Specular color to a red, using the Color Selector dialog box just as you changed the Diffuse color.

2.  Render your scene. Notice there is no difference between your render scene and the sample sphere in the Material Editor.

3.  Change the Specular Level setting to about 70.

4.  Change the Glossiness setting to 10. Notice the difference in the sample sphere.

5.  Render your scene again and look at what are called the specular highlights.

Just because you changed the Specular color does not mean that you will have a colored highlight. You must remember to change the Specular Level and Glossiness values. When changing the values, use the graph to the right as a guide. The higher the curve gets to the top of the graph, the closer the highlight will get to the Specular color. The wider the graph gets, the broader the specular highlight will become.

	TIP If you do not seem to be getting a specular highlight on your objects in your scene but it’s showing up in the sample sphere, change some of the lighting settings in your scene.

Let’s look at material opacity.

1.  Go to the second sample sphere and apply it to the teapot.

2.  Click the Background button in the Material Editor and render the scene.

3.  Go to the Opacity setting, type in 50, and render the scene once again.

Notice the difference in your sample sphere: it is no longer a solid object. (If you are having a hard time seeing this in your scene, place another object behind or inside the teapot.) You can use Opacity for any type of material that you need to see through, even partially. It works well with glass, water, even smoke materials. Remember, you can animate the percentage of Opacity over time.

You can’t just place a light inside a lamp shade in the scene and have it automatically glow. 3D Studio MAX uses a very fast, scanline rendering algorithm that simplifies the complexity that happens in the real world. It abstracts light into a “lighting model” (controlled by shaders) that misses a lot of the subtlety and beauty of physical light. The lighting model does not account for surfaces that glow because of transmitted light. Therefore, a work-around (a cheat) was developed to simulate this phenomenon, called “Self-Illumination.” There are several other examples of where the scanline renderer falls short (inter-object reflected and refracted light). Two completely different algorithms that attempt to approximate real physical light are called Raytracing and Radiosity. Each of them does a better job than the scanline renderer, but the trade-off is increased rendering time. No single algorithm has yet been developed in computer graphics that simulates real light perfectly.

For now, let’s try adding self-illumination.

1.  Go to the third sample sphere and apply it to your teapot.

2.  Render your scene.

3.  Uncheck the Self-Illumination option and, when prompted, type 80 in the box.

4.  Render your scene, looking at the lack of contrast; there are no shaded areas at all.

5.  Check Self-Illumination again and re-render your scene. The teapot is back to normal.

6.  Click the Self-Illumination color swatch.

7.  Change the color and render your scene. This allows you to mix a color with the Diffuse color swatch of the material.

Anisotropic Shader

The Anisotropic shader (see Figure 8.11) works best for creating highlights around elliptical surfaces. The Anisotropic shader gives you more control over the Specular highlights.

FIGURE 8.11  Anisotropic shader basic parameters

Several settings of Anisotropic shaders are new here, not found under Blinn. Diffuse Lev controls the color of the diffuse area. Increasing this value will increase the Diffuse color brightness and decreasing will make it darker, but Diffuse Lev will not affect the specular highlight. The Anisotropy setting controls the shape of the specular highlight. Lower anisotropy values will produce a rounder highlight; higher values will produce a thinner highlight. Finally, Orientation changes the direction of the highlight. Let’s take a look at a couple of the unique options for this shader:

1.  Create a Torus Knot object.

2.  Apply the first material sample to it and render your scene.

3.  Increase the Specular level to 80. Notice the specular highlights.

4.  Increase the Anisotropy level to 85 and render the scene again.

5.  Change the Orientation value to 90 and render.

6.  Decrease the Diffuse level to 35 and render once more.

© 2000, Frol (selection, edition, publication)