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Mastering
3D Studio MAX R3 |
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 colors Value to get a grayish
shade of 150 or so.
- 3. Render your scene again.
Now its time to give your teapot a specular highlight. Many factors
will control the look and size of the highlight. Its 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.
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| TIP If you do not seem to
be getting a specular highlight on your objects in your scene but
its showing up in the sample sphere, change some of the lighting
settings in your scene.
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Lets 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 cant 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, lets 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. Lets 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)
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