What makes a material look the way it does? The primary force in a material is its color. However, there are several ways to describe the color of a material. In 3ds Max, three main parameters control the color of a material: ambient color, diffuse color, and specular color.

Ambient color is the color of a material when it is exposed to ambient light. This essentially means that an object will appear this color in indirect light or in shadow. Ambient gives you the very base color of the object, upon which you add the diffuse and specular colors.

Diffuse color is the color of a material when the object is exposed to direct light. Typically, the ambient and the diffuse colors are not too far apart.

Specular color is the color of a shiny object's highlight. The specular highlight on an object may be controlled by more than just its color—for example, its size and shape. The color, however, sets the tone of the object and, in some cases, the degree and look of its shine.

For example, in a new scene, open the Material Editor by choosing Rendering → Material Editor (Figure 7.3). The spheres you see in the Material Editor represent the materials in the scene. Each tile, or slot, represents one material that may be assigned to one or more objects in the scene. As you click on each slot, the material's parameters are displayed below. You edit the material through the settings you see in the Material Editor.

Select one of the material slots, and click it. Let's change the color of the material. Under the Blinn Basic parameters, click on the gray color swatch next to the Diffuse parameter. This opens the Color Selector window, as shown here.

Using the sliders on the right, you can set the Red, Green, and Blue values for the color, or you can control the color using the Hue, Sat (Saturation), and Value levels. For more on color and RGB/HSV values, see Chapter 1, "Basic Concepts."

You can also very easily select the desired color from the gradient on the left by dragging your mouse over the colors until you find one you prefer. It's best to pick the general color you need from the swatch on the left and then tweak the exact color by using either the RGB or the HSV controls on the right. The Hue of a color represents the actual color itself. The Saturation defines how saturated that color is. The Value sets how bright the color will be.

Once you have a color you like, you simply close the Color Selector. If you want to restart the color, press Reset to zero out any changes. You'll notice that the ambient color changed as well as the diffuse color. You will see why in the next section on the Material Editor itself.

In addition, you can map textures to almost any of the parameters for a material. Notice the blank square icon next to the Diffuse color swatch. Click on that icon, and you will get the Material/Map Browser window, as shown here. The Material/Map browser is used throughout the chapter.

Different materials have different uses. The Standard material is fine for most uses. However, when you require a more complex material, you can change the material type to one that will fit your needs. To change a material type, click the Material Type button called out in Figure 7.3. By default, it displays Standard in the button. Once you click the button, the Material/Map Browser window opens (as shown here) from which you can choose the material type.

Composite

Similar to the Blend, a Composite material combines up to 10 materials, using additive colors, subtractive colors, or opacity mixing (Figure 7.6).

Figure 7.5. The Blend material type allows you to mix two different materials together.

Figure 7.6. The Composite material type allows you to blend up to 10 materials.

Double Sided

The Double Sided material type simply divides the material into two submaterials, one for the outward face and one for the inner face. Figure 7.7 shows the parameters for the material. To set the Facing Material, you can click on the bar to create and edit a new material, or you can click and drag an existing material from the Material Editor onto the Facing Material bar. You set up the Back material in exactly the same way.

In the following graphic, you can see how you can assign one material to the outer face of an object and another one to the back of the surface. Here, a bowl has a solid blue material mapped to the outside, and the inside face is a checkerboard pattern map.

Neither the facing nor the back material need to have 2-Sided enabled for the Double Sided material to render both sides of the surface.

Multi/Sub-Object

Use this material when you need to apply different materials to portions of a 3D object that have different material IDs. You can then assign different surface treatments to a single object. This keeps modeling simpler because you do not have to make separate objects for everything that needs a different material.

Figure 7.7. A Double Sided material allows you to assign two materials to either side of a surface.

Figure 7.8. The Ink 'n Paint material's parameters

Figure 7.9. A Cartoon-shaded render using the Ink 'n Paint material

The way light reflects from a surface defines that surface to your eye. In 3ds Max, you can control what kind of surface you work with by changing the Shader type for a material. This option will let you mimic different types of surfaces such as dull wood or shiny paint or metal. The following descriptions outline the differences in how the Shader types react to light.

Anisotropic

The Anisotropic shader (shown in the following graphic) is good for surfaces that are deformed, such as foil wrappers or hair. Anisotropic is defined as having properties that differ according to direction. This creates a specular highlight that is uneven across the surface, changing according to the direction you specify on the surface. The other surface types, as you will see in this section, typically create rounded specular highlights that spread evenly across a surface. Figure 7.12 shows the Material Editor for an Anisotropic material. Notice the extra controls for the specular highlights. These allow you to control how the specular will fall across the surface.

Figure 7.10. The Shellac material allows you to superimpose a shiny layer on top of another material

Figure 7.11. The Top/Bottom material type

Blinn

This is the default material in 3ds Max because it is a general-purpose, flexible shader. The Blinn shader (shown here) creates a smooth surface with some shininess. If you set the specular color to black, however, this shader will not display a specular and will lose its shininess, making it perfect for regular dull surfaces, such as paper or an indoor wall. Figure 7.13 shows the Blinn shader controls in the Material Editor.

Because this is the most-often used shader, let's take a look at its Material Editor controls. The ambient, color, and specular colors all work as you've seen earlier in this chapter. You simply set the color you want by clicking the color swatch, or you can map a texture map to any of these parameters by clicking the Map button and choosing the desired map from the Material/Map Browser window.

SPECULAR HIGHLIGHT CONTROLS

The parameters in the Specular Highlights section of the Blinn Basic Parameters rollout are interesting for this shader. The specular color, which defaults to white, controls the color of the highlight. Decreasing the brightness of that specular color, whatever the color may be, will decrease the brightness of the specular highlight on the object, making it seem less shiny. Changing the specular color to black will negate any surface shine.

Figure 7.12. Material Editor for the Anisotropic material

Figure 7.13. The Specular Level of a Blinn controls the amount of highlight on the surface.

The surface shine is also regulated by the Specular Level parameter. The higher the value, the hotter the specular highlight will render on the object. Figure 7.14 shows a sphere with a Blinn with a Specular Level of 0 on the left, a Specular Level of 35 in the middle, and a Specular Level of 100 on the right.

The Glossiness parameter controls the width of the specular highlight. With the same sphere with a Specular Level of 35, Figure 7.15 shows you a Glossiness of 0 on the left (which creates a broad specular), a Glossiness of 35 in the middle (which creates a fairly tight, shiny specular highlight), and a Glossiness of 75 on the right (which creates a high gloss pin point specular highlight). The higher the value, the glossier the surface will appear.

Finally, the Soften parameter controls the softness of the specular highlight. Figure 7.16 shows a sphere with a Blinn material assigned with a Specular Level of 55, a Glossiness of 10, and with a Soften value of 0 on the left and a Soften value of 1 (the max) on the right.

Figure 7.14. The Specular Level of a Blinn controls the amount of highlight on the surface.

Figure 7.15. The Glossiness parameter controls the width of the specular highlight.

Soften controls the specular breadth on specular highlights that are already broad—that is, they have lower Glossiness values. You may want to look at these parameters at work in a Max scene, as your monitor will display the specular highlights better than a printed page.

You've probably noticed the graph (shown here) in the Material Editor when you work with the Specular Level, Glossiness, and Soften parameters. This graph shows you the falloff of the specular you are editing for the material. The shorter the graph, the lower the level of specular highlight. The rounder the graph, the broader and softer the specular highlight.

For shiny objects, you will need to use a fairly sharp specular. For extremely shiny objects, such as polished metals, a pinpoint specular is best. Plastic objects will work best with a broad, diminished specular. Matte objects, such as paper or cloth, work great without a specular highlight, or at least a very darkly colored one.

SELF-ILLUMINATION AND OPACITY

The Self-Illumination parameter adds incandescence to the material, as if the object is giving off its own light. The higher this value, the flatter the object will appear, because Self-Illumination will essentially negate any shadowing or ambient falloff on the material. The specular highlights on the material will still show up on a material with Self-Illumination turned all the way up to 1.0. You can also change the color of the Self-Illumination by clicking the Color check box and choosing a color in the swatch that appears when Color is enabled. This allows you to have a different incandescence color than the color of the material itself. Figure 7.17 shows a Self-Illumination value of 0 on the left and a Self-Illumination value of 1.0 on the right. Notice how the sphere flattens out as Self-Illumination helps keep the shadow areas as bright as the diffuse.

Figure 7.16. The Soften parameter helps reign in broad specular highlights by softening their edges.

Figure 7.17. The Self-Illumination value sets the incandescence of a material.

Note

A Self-Illumination value does not emit a light in the default scanline renderer-that is, the object will not illuminate other objects in the scene. For such an effect, you will need to use more advanced rendering techniques with mental ray, for example.

Finally, the Opacity setting sets the transparency of an object, as you may have read earlier in the chapter. The higher the Opacity value, the more solid it renders. The lower the Opacity value, the more see-through the object will render.

Metal

The Metal shader is not too different from the Blinn shader. Metal creates a lustrous metallic effect, with much the same controls as a Blinn shader, but without the effect of any specular highlights. When you are first starting, it's best to create most of your material looks with the Blinn shader, until you're at a point where Blinn simply cannot do what you need. The following graphic displays a sphere with a Metal shader with a Specular Level of 120 and a Glossiness of 60.

The black areas of the shader may throw you off at first, but keep in mind that a metallic surface is ideally black when it has nothing to reflect. Metals are best seen when they reflect the environment. As such, this shader requires a lot of reflection work to make the metal look just right.

Multi-Layer

With some surfaces, you need complex highlights. In some cases, while an Anisotropic might be useful, you may need further control in the complexity of your specular shape and falloff. A Multi-Layer shader will stack two Anisotropic highlights together to give you increased control over the highlights you can create.

Here you can see a Multi-Layer material assigned to a sphere. The two layered specular highlights are created in such a way, as seen in Figure 7.18, to create an "X" formation for the highlight.

Oren-Nayar-Blinn

The Oren-Nayar-Blinn shader (shown here) generally creates good matte surfaces such as cloth or clay. The shader has specular highlight controls very similar to those of the Blinn shader.

Phong

By all accounts, the Phong shader (shown here) looks very similar to the Blinn shader, and it has the same controls. Phong creates smooth surfaces with some amount of shininess, just as Blinn does. However, Phong does not handle highlights as well as Blinn. This is especially true for glancing highlights, where the edge of a surface catches the light. Phong is good for creating plastic objects, as well as many other surfaces.

Figure 7.18. The Multi-Layer shader lets you create complex highlights.

Figure 7.19. A Translucent shading material allows light to scatter through the object.

Note

Phong is a legacy shader that was created before the introduction of the Blinn shading model.

Strauss

The Strauss material (shown here) can create metallic and nonmetallic surfaces. Its main controls are Color, Glossiness, Metalness, and Opacity. The specular highlights, for the most part, are governed by the Glossiness of the material. The higher the Metalness value, the darker the unlit portions of the surface become, again relying on reflections for the metallic look.

Translucent

The Translucent shader (shown here) is very similar to the Blinn; however, this shader adds a touch of translucency to the material. Translucence is where light is scattered as it passes through the material—for example, a flashlight shining behind a parchment. You can also simulate frosted and etched glass by using translucency. Figure 7.19 shows the Material Editor for a Translucent shader material.

You can begin with your own project, or you can copy the PoolBall project found on the companion CD to your hard drive. It contains a texture image file you'll need for this exercise.

The next step is to decide what the surface of your object is going to be. Will it be shiny or matte? You will need a shiny surface, because real pool balls are glossy. We will have to adjust the specular highlights using the Blinn's controls.

The material is now linked to the material on the object. If you were to change any of the parameters of the material, it would be instantly updated on the object. For the most part, once a material is applied it cannot be deleted—it can only be replaced with another material. You cannot go back to the default color of the original object.

Figure 7.20 shows you what the pool ball should look like, most noticeably its specular highlight. However, viewing in the viewport isn't the same as a rendered image. The viewport gives the lowest level of quality, and it should not be used to make final decisions on the look of your material. Instead, it should be used as a point of reference. Figure 7.21 shows this pool ball rendered. Rendering combines the materials, lights, shadows, and environments within a scene to create the final look. Rendering will be covered in detail in Chapter 11. Notice how much more detailed the specular highlight is in the render. To check your render, simply click the Quick Render icon (

Figure 7.20. The pool ball in a viewport

Figure 7.21. The pool ball rendered

This simple material is only part of the story. You still need to add the markings of a real pool ball, not just a solid color. Just creating a sphere and making it shiny and green doesn't make a realistic ball. Figure 7.22 shows some real pool table balls. Pool balls have a graphic strip or number in a circle. You can't create this detail using the basic parameters of the Standard material. What you need is a bitmap.

A bitmap replaces the diffuse color with an image. The image you use can be hand drawn and scanned, created in a program such as Adobe Photoshop, or taken with your digital camera. The image we are going to use was created in Photoshop (Figure 7.23). A white circle with a "2" is in the middle and then one that is cut in half is on either side. This has to do with texture placement. As you gain more experience, you'll learn how to prepare your texture images for your models.

Figure 7.22. Pool balls

Figure 7.23. The proposed bitmap texture for the ball

The theory behind this image is quite simple. Pool balls have the number on opposite sides of the ball. In your texture map, you'll need to make two 2s in the blue backdrop. The two halves of the white circle and the 2 will simply tile together when the texture image wraps around the sphere, much the way a wrapper wraps around a candy. Mmm85Candy. This way you have two 2s on the ball, easy as pie. To apply this bitmap as a texture, follow along here:

With the image applied, the pool ball looks pretty good at this point (Figure 7.27)—but it's not perfect. The small nuances are what really make a render look good. One thing this pool ball is missing is a reflection of its environment. Now, short of creating and texturing a pool table and several other pool balls, we need to make a cheat.

There are two ways to create reflections: the "cheat" method by mapping and using raytrace. Both methods require us to go to the Maps rollout in the Material Editor. We are going to add a bitmap into the Reflections Map slot. We are going to use the "fake it" method.

To fake the reflection, you'll need an image that looks like the "room" around the ball. We are going to use a photograph taken for this occasion and saved as the image file ReflectionMap.tif in the Sceneassets Images folder of the PoolBall project on the companion CD (Figure 7.28).

This image has all the elements that you might see around a pool ball—specifically, more pool balls! To add this image as a reflection for the ball, follow these steps:

Figure 7.30. The reflections look much better and add a certain realism to the pool ball.

You may notice that the background in the renders in Figures 7.29 and 7.30 are white, whereas your renders' backgrounds are probably black. A simple setting change and there are many reasons why you would want to control this option. You may want a specific color to offset your scene (for example, blue to represent the sky) or you may want a picture in your background.

To change the background of your renders, go to the main menu and choose Rendering → Environment (shown here). The Background parameter is at the top of the dialog box. Click on the color swatch and choose your color. That's it!

To add an image to the background, click on the bar marked None to add a bitmap, just as you did with the bitmaps on the pool ball. Once you do, the image will render in the background with your scene. To change the image, click on that bar, which at that point should list the path and filename of the current image, to take you to the Material/Map browser where you can select a new bitmap and image.

If you have a scene with several materials, and you need to see more sample slots than the default in the Material Editor, simply right-click on any slot and select either 5 × 3 Sample Windows or 6 × 4 Sample Windows from the context menu. This will help you navigate a heavy scene that has tons of materials that you need to modify. In the following graphics, you can see the sample slots multiply!

As you've seen, the sample slots for any given material in the Material Editor constantly update to show you any changes you've made to that material. However, if you want a larger image than the relatively small sample slot, right-click on the slot and select Magnify from the context menu, as shown in Figure 7.33. 3ds Max will open a larger window (Figure 7.34), which is resized by dragging the corners of the window, with a sample of that material. It will by default update automatically as you make changes to the material.

Figure 7.33. Magnify gives you a larger view of your material.

You've already noticed that there are only 24 sample slots in the Material Editor. This does not limit the number of materials you can use to 24. You should consider the Material Editor as a scratchpad of sorts. You can create as many materials as you'd like in a 3ds Max scene; however, at any one time, only 24 can be loaded in the Material Editor window at the same time.

Figure 7.34. A larger view of your material sample

If you click the Get Material button in the Material Editor, you can list all the materials that are used in the scene. When the Material/Map browser is open, click the Scene radial button for the Browse From parameter, and all of the materials assigned in the scene will be listed. When an object's material is not shown in a sample slot, it does not mean it has been deleted. You can load it back into any sample slot for editing at any time.

You've seen several times how to assign a material to an object. You can, for instance, drag the material from the Material Editor to the object in a viewport. You can also select an object in the viewport, and then select a Sample Slot material and click the Assign Material to Selection button (

However, you may want to assign materials to sub-object polygons as well as whole objects. One approach is to use the Multi/Sub-Object material type briefly discussed earlier in the chapter (the Multi/Sub-Object material will not be covered in this book, as it is beyond the beginner scope).

There is a much easier way to assign materials to sub-objects, however. Just select the appropriate polygons on the surface (the object must be an editable mesh or poly, or have an Edit Mesh/Edit Poly modifier applied), and assign the material as you regularly would (with the Assign Material to Selection button or drag the material to the selected polygons in the viewport). A sphere with several polygons assigned to different materials is shown in Figure 7.35.

Once you apply a material to a sub-object, a new Multi/Sub-Object material is created in the scene automatically. You can load the new Multi/Sub-Object material by using the eyedropper to click on the object in the viewport to load the material into a sample slot.

Figure 7.35. Applying materials to a mesh's Sub- Object polygons is easy.

2D maps are two-dimensional images that are typically mapped onto the surface of geometric objects or used as environment maps to create a background for the scene. The simplest 2D maps are bitmaps; other kinds of 2D maps are generated procedurally.

Procedural maps are generated entirely within 3ds Max and rely on a set of parameters you set for their look. Images brought in the way the pool ball's color and reflection maps were brought in are not procedural. They are bitmaps —that is, raster image files. For more on raster image files, see Chapter 1.

Click on the 2D Maps category in the Material/Map browser to see the available 2D maps.

Checker

A procedural map, the checker map is a checkerboard pattern that is generated in 3ds Max. Its parameters in the Material Editor, which are shown here, control the look of the checkerboard. A sphere is also shown with a checker applied to its color.

The Tiling values under the Coordinates rollout determine the number of checkers. The higher the number, the more checkers. Color #1 and Color #2, of course, control the two colors of the checkerboard; black and white are defaults. Click on the color swatch to change the color, or you can click the Maps bars next to each color (labeled None until you assign a map). Also, the Blur parameter allows you to blur the edges of the checkers, and the Soften parameter under the Checker Parameters rollout blurs the checkers together.

Gradient

A gradient i s a procedural map (the parameters are shown here) that grades from one color to a second color that grades to a third color. Here, a cylinder is shown grading from black (top) to white (bottom).

In the Coordinates rollout, the parameters are much the same as they are for the Checker map. These coordinates are pretty much the same for all procedural maps, as they allow you to position the map as you need on the object by setting the options such as Tiling and Offset.

The colors for the gradient are set by Color #1, Color #2, and Color #3. You can also map these colors. The Color 2 Position parameter sets the relative location of the middle color to the upper and lower colors—i.e., 0.5 is the middle because the other colors are at 0 and 1.0.

Gradient Ramp

Similar to the Gradient map, but much more powerful, the Gradient Ramp is a procedural map that allows you to grade from and to any number of grayscale shades. Here, a gradient is shown in the Material Editor that is applied to a cube.

Use the sliders along the ramp in the Material Editor to set the position of the gray value. Click in the ramp to create a new slider at that grayscale value. The Black and White sliders at the very ends do not move. To delete a slider, right-click on it, and choose Delete from the context menu that appears. Notice the value and position readout above the ramp.

Gradient Ramps are perfect for creating maps that fall off (for example, for opacity affects where the opacity fades away).

Similar to 2D maps that are generated in two dimensions, 3D maps are patterns generated procedurally in all three dimensions. For example, Marble has a grain that goes through the assigned geometry in X, Y, and Z. If you cut away part of an object with Marble assigned as its texture, the grain in the cutaway portion matches the grain on the object's exterior.

When you create a 3D map, notice that the Coordinates rollout has Tiling and Offset parameters in three axes, whereas the 2D maps only have X and Y.

Try using some of the 3D maps (such as Marble, Wave, Stucco, and Wood) to see how they work on a simple object in your scene. They all have basically the same Coordinates rollout; however, each has its own Parameters rollout to control the color and other settings.

Marble

A Marble map creates veins of colors that run through an object. The 3D aspect of the map allows it to spread across all three dimensions, creating a more realistic texture. Color #1 and Color #2 control the two colors of a Marble map, while the third color is a grainy blend of the two together.

The Marble map's parameters are shown applied to a cube, which is also shown here.

Noise

Noise is a great way to easily add some randomness to a parameter or to add a bit of randomness to a surface's color or specular highlight, for example. Its parameters and a sample cylinder are shown here.

Used sparingly, noise can add great detail to highlights for any shiny object when mapped to the specular color. In this case, just make sure the colors in the noise do not contrast too much against each other, which would make the map faint.

Wood

Wood is a quick way to add wood grain to a material. Its parameters and a sample cylinder are shown here.

Just like the Marble map, you can set the color of the wood grain with Color #1 and Color #2. Adding Radial Noise and Axial Noise will make the wood appear to have more burls.

Compositors are meant specifically for compositing colors or maps together for some advanced effects. In image processing, compositing images refers to superimposing two or more images to combine them in a variety of ways.

Color Modifier maps alter the color of pixels in a material for some advanced effects. Color modifiers and Compositor maps will not be covered in this book.

To begin, you will create a chess piece (Figure 7.36) to learn about bump mapping and using reflections to create the illusion of shine and dents on the surface of the object. Just follow these steps:

Figure 7.37. That's not a chess piece yet!

Adding Shine

The next step to making this piece more realistic is to add shininess, which you will accomplish in two actions.

1. Go back to the Material Editor. In the Material, change the Specular Level to 95 and Glossiness to 90. Your sample material should have a nice specular, as shown here.

2. The second part to making the piece shinier is to add a touch of reflection. Go to the Maps rollout and select the bar next to Reflection. You are going to add a bitmap to fake a reflection, as you did with the pool ball earlier in the chapter. In the Material/Map browser, select Bitmap.

3. 
   

   Figure 7.38. This bitmap will serve as a reflection for the chess piece.

4. Choose the Reflect Map.tif image. When you map a reflection, it is important to find an image that will be believable in your scene. Ideally, it should be the room around the object. In this case, you just want a little something to reflect faintly in the chess piece.

   

   Figure 7.39. The chess piece with a slight reflection map

5. Select the Go to Parent button (

   

Applying a Bump

Bump mapping is very common in CG. It adds a level of detail to an object fairly easily by creating bumps and grooves in the surface and giving the object a tactile feel in its appearance.

Bump mapping takes the intensity values of an image or procedural map to simulate bumpiness on the surface of the model, without changing the actual topology of the model itself. You can create some surface tactile texture with a bump map; however, you will not be able to create extreme depth in the model. For that, you may want to model the surface depth manually or use displacement mapping. Displacement maps are not covered in this book because they are a more advanced mapping technique.

Note

Displacement mapping is used to change the topology of the model, whereas bump mapping uses light and dark in the colors of the render to trick the eye into seeing surface detail.

To apply a bump map to the chess piece, follow these steps:

1. While still in the Maps rollout for your chess piece material, click on the bar labeled None next to the Bump. We are going to use another Dent map. Select Dent from the Material/Map browser. Change the Size to 400 and change the Strength to 2.0. Do not change the colors because you want the map to be black and white. Bumps work best when you are using high-contrast maps. Leave all the other parameters at their defaults. Quick render your scene and your chess piece should look like Figure 7.40. You can play around with the Size and Strength and Iterations to achieve different looks.

2. Click the Go to Parent icon to get back to the Material parameters and go to the Maps rollout. You can play around with the Bump amount until you have an acceptable result. Also, remember that the amount of bump you use will also depend on how close the object is to camera. The farther away an object is, the less visible the bump will be.

Let's try a slightly different look now using the following steps:

1. Go to the Material Editor. Select the red plastic material you created in the previous exercise.

2. Click the Go to Parent button to get back to the Material parameters and go to the Maps rollout.

   

   Figure 7.40. Adding a bump helps the chess piece look more realistic. You can add a lot of character to an object through its bump mapping.

3. Select the bar labeled None next to the Diffuse Color. Navigate to where the maps are and select Wood1.jpg from the Texture Scene Files folder on the CD. This bitmap image will replace the red diffuse color. You won't see the change in the viewport until you select the Show Map in Viewport icon (

   

4. Render and you will see that the wood image has wrapped itself around the chess piece. You can edit the image through the Coordinate rollout (shown here) in the Bitmap parameters. Offset U will move the image horizontally. Offset V will adjust it vertically. Tiling scales the image, and Angle will rotate it across the surface.

   

Later in the chapter, you will learn a more efficient way to edit the image on the object, known as UVW mapping.

Figure 7.41. The chain link texture

Opacity mapping allows you to cut out parts of an object by making those parts invisible. You can also create wonderful fading effects using Opacity maps. With opacity mapping, you don't have to model certain details, which can be a real time saver. In this example, you will create a chain link fence. However, you will not model a fence. You will create it entirely from mapping. To make a chain link fence, follow these steps:

You can see immediately how useful opacity mapping can be. 3ds Max uses the white portions of the image map to display full opacity, whereas the black areas become transparent. If you did not have an opacity file such as the one in this exercise, you could easily create one by painting a black-and-white matte of the color image that you are using for the material.

Now let's take a look at how to apply a UVW Map Modifier in a scene. The following exercise examines the use of the UVW Map modifier:

In many situations, a material needs to appear the same when applied to several different objects. For example, two different sections of a roof may need to appear with identical mapping even though they are different sizes. The UVW Map modifier includes the Acquire tool for matching one object's mapping gizmo to another's, as shown in the following exercise.

As with any other modifier in the modifier stack, the UVW Map modifier is applied to the result of the modifier or object below it in the stack. This must be considered when you are locating the modifier or the preferred result may occur. For example, Box mapping has a different result when it is applied to a box before it is bent than when it is applied after it is bent.

As you can see, the location of the UVW Map modifier in the stack impacts the final appearance of the objects.