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Mastering 3D Studio MAX R3

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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 nature’s 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 refracts—it 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.

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
Ambient Sets the color of your object in shadow or indirect light
Diffuse Sets the color of your object in direct light
Reflect Sets the color of the specular reflection
Specular Color Sets the color of the highlight on a shiny, curved surface
Specular Level Sets the intensity of the specular highlight
Glossiness Controls the size of the specular highlight
Soften Softens the edge of the specular highlight
Luminosity Replaces shadowed surfaces with the diffuse color
Transparency Determines the transparency of a material and assigns it a filter color that affects the objects behind it
Index of Refraction Controls how much a transparent object distorts objects
Environment Specifies an environment map for reflection and refraction that overrides the scene environment map
Bump Specifies a bump map in the same way a Standard material does; uses the bitmap values to construct texture shading.


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 don’t update one another.)

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

Let’s 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.

TIP For faster rendering, turn off Raytrace Refractions in the Raytracer Controls rollout.


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.

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 object’s thickness, and to gradually fill the walls of the object with fog so that it becomes opaque.


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