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Mastering
3D Studio MAX R3 |
CHAPTER 9
Advanced Materials
Featuring
- Understanding Raytrace Materials
- Applying Maps to a Raytrace Material
- Creating Matte/Shadow Materials
- Building Compound Materials
- Using Materials Features New to R3
- Understanding Camera Mapping
In Chapter 8, we examined surface shading using the
most common material types. In this chapter, you will learn how to shade
surfaces with more specialized types of materials, including Raytrace,
Matte/Shadow, and five compound material types.
Understanding Raytrace
Materials
Materials control how MAX renders surfaces. One of the most beautiful
materials, the Raytrace material, simulates photo-realistic, detailed,
surface shading effects (see Figure 9.1). It provides in-depth controls
for reflection, refraction, transparency, translucency, and fog, as well
as many of the basic controls found in the Standard material type.
If you are just going to raytrace a reflection or refraction, you might
want to consider using a Raytrace map within a Standard material. The
Raytrace map type uses the same raytrace algorithm as the Raytrace material,
so it is equally accurate, but the map renders a little bit faster. Another
plus is that the Raytrace map gives you extra controls for anti-aliasing
and attenuation, while including many of the same mapping and effects
features found in Raytrace materials.
In the Material Editor, Raytrace materials have five rollouts of parameter
settings: Basic Parameters, Extended Parameters, Raytracer Controls, Maps,
and Dynamics Properties.
FIGURE
9.1 Use Raytrace materials to simulate some
of natures most beautiful lighting effects, such as the refraction
of light through glass.
Reflections vs. Refractions
Light creates reflections when it bounces off of shiny surfaces.
The angle of the surface relative to the source of light determines
the direction that light reflects.
When light shines through a transparent substance, it refractsit
shifts course laterally but continues along a path close to the
original. This causes images that are seen through transparent substances
to appear shifted, like a pole that seems bent when you place it
in water. The amount of this shift is determined by an optical property
of the substance called the index of refraction, or IOR.
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Setting Basic
Parameters
Basic parameters for Raytrace materials (shown in Figure 9.2 and listed
in interface order in Table 9.1) extend the basic parameters for Standard
materials. In Raytrace, Ambient is defined as how much ambient color the
shadow will absorb. Setting the Ambient color to white is the same as
locking it to the Diffuse color in Standard materials. Diffuse and Specular
settings work in the same way as they do in Standard materials.
FIGURE
9.2 Control your Raytrace materials with this
rollout.
Table 9.1: KEY RAYTRACE BASIC PARAMETERS
Parameter
| Function
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Ambient
| Sets the color of your object in shadow
or indirect light
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Diffuse
| Sets the color of your object in direct
light
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Reflect
| Sets the color of the specular reflection
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Specular Color
| Sets the color of the highlight on a shiny,
curved surface
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Specular Level
| Sets the intensity of the specular highlight
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Glossiness
| Controls the size of the specular highlight
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Soften
| Softens the edge of the specular highlight
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Luminosity
| Replaces shadowed surfaces with the diffuse
color
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Transparency
| Determines the transparency of a material
and assigns it a filter color that affects the objects behind it
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Index of Refraction
| Controls how much a transparent object
distorts objects
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Environment
| Specifies an environment map for reflection
and refraction that overrides the scene environment map
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Bump
| Specifies a bump map in the same way a
Standard material does; uses the bitmap values to construct texture
shading.
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| NOTE Unchecking
any of the boxes next to the color swatches in the Basic Parameters
rollout accesses a grayscale spinner. This spinner controls how much
a parameter affects a material, from zero to 100 percent. Setting
this value is the same as checking the box and changing the color
swatch from black through the gray values to white. Whether the grayscale
spinner or the color swatch is displayed, MAX always uses the visible
parameter, and ignores the parameter that is not displayed. (They
can indeed differ, and they dont update one another.)
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Transparency works like a combination of Opacity and Filter in a Standard
material, except that Transparency settings work in inverse proportion
to settings for Opacity. Additional parameters include reflection, index
of refraction, environment mapping, and bump mapping. For an example of
a raytraced image reflecting the scene around it, see Figure 9.3.
FIGURE
9.3 A raytraced sphere reflecting the scene
around it
Creating a Raytraced Reflection
Lets create a raytraced reflection like the one in Figure 9.3.
- 1. Create a plane and assign it a checker mapped
material.
- 2. Create a sphere that sits on the plane.
- 3. Assign an environment map to the background.
- 4. Open the Material Editor.
- 5. Select an available sample slot.
- 6. Click the Type button and select Raytrace from
the list of new materials.
- 7. In the Raytrace Basic Parameters rollout, change
the Reflect color swatch to white or uncheck the box and set
the grayscale spinner to 100.
- 8. Assign the same bitmap that you used in the scene
environment to the local environment map.
- 9. Assign the material to the sphere.
- 10. Render the scene.
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| TIP For faster
rendering, turn off Raytrace Refractions in the Raytracer Controls
rollout.
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| TIP The Reflection
parameter overrides the Transparency parameter. If you set the Reflection
grayscale spinner to 100% or set the swatch to white, the object will
be completely opaque, regardless of its Transparency value.
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Setting Extended
Parameters
Extended parameters for Raytrace materials (detailed in Table 9.2 and
Figure 9.4) allow you to simulate extra light, translucency, and fluorescence,
and give you finer control over transparent and reflective surfaces. The
Density settings allow you to apply a tint to a transparent material based
on the objects thickness, and to gradually fill the walls of the
object with fog so that it becomes opaque.
© 2000, Frol (selection,
edition, publication)
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