The Blend material blends two separate materials on a surface. The Blend Basic Parameters rollout, shown in Figure 16.1, includes buttons for loading the two submaterials. The check boxes to the right of these buttons enable or disable each submaterial. The Interactive option enables you to select one of the submaterials to be viewed in the viewports.

The Mask button (which appears below the two submaterial buttons) lets you load a map to specify how the submaterials are mixed. Gray areas on the map are well blended, white areas show Material 1, and black areas show Material 2. As an alternative to a mask, the Mix Amount determines how much of each submaterial to display. A value of 0 displays only Material 1, and a value of 100 displays only Material 2. This value can be animated, allowing an object to gradually change between materials.

Figure 16.1. The Blend material can include a mask to define the areas that are blended.

The Mixing curve defines the transition between edges of the two materials. The Upper and Lower spinners help you control the curve.

The Composite material mixes up to ten different materials by adding, subtracting, or mixing the opacity. The Composite Basic Parameters rollout, shown in Figure 16.2, includes buttons for the base material and nine additional materials that can be composited on top of the base material. The materials are applied from top to bottom.

Figure 16.2. Composite materials are applied from top to bottom, with the last layer placed on top of the rest.

You enable or disable each material using the check box to its left. The buttons labeled with the letters A, S, and M specify the opacity type: Additive, Subtractive, or Mix. The Additive option brightens the material by adding the background colors to the current material. The Subtractive option has the opposite effect and subtracts the background colors from the current material. The Mix option blends the materials based on their Amount values.

To the right of the A, S, and M buttons is the Mix amount. This value can range from 0 to 200. At 0, none of the materials below it will be visible. At 100, full compositing occurs. Values greater than 100 cause transparent regions to become more opaque.

The Double Sided material specifies different materials for the front and back of object faces. You also have an option to make the material translucent. This material is for objects that have holes in their surface. Typically, objects with surface holes do not appear correctly because only the surfaces with normals pointing outward are visible. Applying the Double Sided material shows the interior and exterior of such an object.

The Double Sided Basic Parameters rollout includes two buttons, one for the Facing material and one for the Back material. The Translucency value sets how much of one material shows through the other.

You can use the Multi/Sub-Object material to assign several different materials to a single object via the material IDs. You can use the Mesh Select modifier to select each subobject area to receive the different materials.

At the top of the Multi/Sub-Object Basic Parameters rollout, shown in Figure 16.3, is a Set Number button that lets you select the number of subobject materials to include. This number is displayed in a text field to the left of the button. Each submaterial is displayed as a separate area on the sample object in the sample slots. Using the Add and Delete buttons, you can selectively add or delete submaterials from the list.

Figure 16.3. The Multi/Sub-Object material defines materials according to material IDs.

Each submaterial includes a sample preview of the submaterial and an index number listed to the left, a Name field where you can type the name of the submaterial, a button for selecting the material, a color swatch for creating solid color materials, and a check box for enabling or disabling the submaterial. You can sort the submaterials by clicking the ID, Name, or Sub-Material buttons at the top of each column.

After you apply a Multi/Sub-Object material to an object, use the Mesh Select modifier to make a subobject selection. In the Material section for this subobject selection, choose a material ID to associate with a submaterial ID or select the material by name from the drop-down list.

When I think of patches, I think of a 3D Max object type, but for many people, "patches" instead bring to mind small scraps of cloth used to make a quilt. Because they share the same name, this example uses Max patches to create a quilt. You can then use the Multi/Sub-Object material to color the various patches appropriately.

To create a quilt using patches, follow these steps:

Figure 16.4 shows the finished quilt. Because it's a patch, you can drape it over objects easily.

The Morpher material type works with the Morpher modifier to change materials as an object morphs. For example, you can associate a blushing effect with light red applied to the cheeks of a facial expression to show embarrassment. You can use this material only on an object that has the Morpher modifier in its Stack. The Morpher modifier includes a button called Assign New Material in the Global Parameters rollout for loading the Material Editor with the Morpher material type.

Figure 16.4. A quilt composed of patches and colored using the Multi/Sub-Object material

For the Morpher material, the Choose Morph Object button in the Morpher Basic Parameters rollout lets you pick a morpher object in the viewports and then open a dialog box used to bind the Morpher material to an object with the Morpher modifier applied. The Refresh button updates all the channels. The base material is the material used before any channel effects are used.

The Morpher material includes 100 channels that correlate to the channels included in the Morpher modifier. Each channel can be turned on and off. At the bottom of the parameters rollout are three Mixing Calculation options that can be used to determine how often the blending is calculated. The Always setting can consume lots of memory and can slow down the system. Other options are When Rendering and Never Calculate.

The Shell Material consists of an original material and a baked material. For each of these materials, you can specify which appear in the viewport and which are rendered.

The Shellac material is added on top of the Base material. The Shellac Basic Parameters rollout includes only two buttons for each material, along with a Color Blend value. The Blend value has no upper limit.

The Top/Bottom material assigns different materials to the top and bottom of an object. The Top and Bottom areas are determined by the direction in which the face normals point. These normals can be according to the World or Local Coordinate System. You can also blend the two materials.

The Top/Bottom Basic Parameters rollout includes two buttons for loading the Top and Bottom materials. You can use the Swap button to switch the two materials. Using World coordinates enables you to rotate the object without changing the material positions. Local coordinates tie the material to the object.

The Blend value can range from 0 to 100, with 0 being a hard edge and 100 being a smooth transition. The Position value sets the location where the two materials meet. A value of 0 represents the bottom of the object and displays only the top material. A value of 100 represents the top of the object, and only the Bottom material is displayed.

There's nothing like hitting the surf early in the morning, unless you consider hitting the virtual surf early in the morning. As an example of a compound material, you apply the Top/Bottom material to a surfboard.

To apply a Top/Bottom compound material to a surfboard, follow these steps:

Figure 16.5 shows the resulting image.

Figure 16.5. A rendered image of a surfboard with the Top/Bottom compound material applied

Sometimes you may want to apply multiple materials to a single part. Selecting subobject areas and using material IDs can help you accomplish this task.

Many of the standard primitives have material IDs automatically assigned: Spheres get a single material ID, boxes get six (one for each side), and cylinders get three (one for the cylinder and one for each end cap). In addition to the standard primitives, you can assign material IDs to Editable Mesh objects. You also can assign these material IDs to any object or subobject using the Material modifier. These material IDs correspond to the various materials specified in the Multi/Sub-Object material.

As an example of mapping multiple materials to a single object, consider a die. Splitting the cube object that makes up the die into several different parts wouldn't make sense, so you'll use the Multi/Sub-Object material instead.

To create a die model, follow these steps:

Figure 16.6 shows a rendered image of two dice being rolled.

Tip

If you enable the Show Map in Viewport option in the Material Editor, then the subobject materials are visible; you also can enable them using the Views

All compound materials have submaterials that are used to add layers of detail to the material, but if these submaterials aren't used, they can take up memory and disk space. You can locate and eliminate unused submaterials in the scene using the Clean MultiMaterial utility. This utility can be accessed from the Utility panel or from the Utilities menu in the Material Editor. For example, if you create a Multi/Sub-Object material with seven submaterials but later as you are modeling find that you need only five, the two unneeded submaterials can be cleaned.

Clicking the Find All button finds all submaterials that aren't used and presents them in a list where you can select the ones to clean.

Figure 16.6. These dice have different bitmaps applied to each face.

The Material modifier lets you change the material ID of an object. The only parameter for this modifier is the Material ID. When you select a subobject and apply this modifier, the material ID is applied only to the subobject selection. This modifier is used in conjunction with the Multi/Sub-Object Material type to create a single object with multiple materials.

The MaterialByElement modifier enables you to change material IDs randomly. You can apply this modifier to an object with several elements. The object needs to have the Multi/Sub-Object material applied to it.

The parameters for this modifier can be set to assign material IDs randomly with the Random Distribution option or according to a desired Frequency. The ID Count is the minimum number of material IDs to use. You can specify the percentage of each ID to use in the fields under the List Frequency option. The Seed option alters the randomness of the materials.

The MaterialByElement modifier enables you to change material IDs randomly. In this tutorial, you reproduce the effect of lights randomly turning a marquee on and off by using the Multi/Sub-Object material together with the MaterialByElement modifier.

To create a randomly lighted marquee, follow these steps:

Figure 16.7 shows the marquee with its random lights. (I've always wanted to see my name in lights!)

You can change the geometry of an object in several ways using a bitmap. One way is to use the Displace modifier (found in the Modifiers

Another way to displace geometry with a bitmap is to use a displacement map. Displacement maps can be applied directly to Editable Poly and Mesh, NURBS, and Patch objects. If you want to apply a displacement map to another object type, such as a primitive, you first need to apply the Modifiers

Figure 16.7. This marquee is randomly lighted, thanks to the MaterialByElement modifier.

One drawback to using displacement maps is that you cannot see their result in the viewport, but if you apply the Modifiers

When faced with how to displace an object using a bitmap, Max once again comes through with several ways to accomplish the task. The method you choose depends on the pipeline. You can choose to keep the displacement in the Modifier Stack or on the material level. This simple tutorial compares using both these methods.

To compare the Displace modifier with a displacement map, follow these steps:

Figure 16.8 shows the resulting displacement on both plane objects.

Figure 16.8. Objects can be displaced using the Displace modifier or a displacement map.

Vertex colors can be assigned in the Surface Properties rollout for Editable Mesh and Editable Patch objects, and in the Vertex and Polygon Properties rollouts for Editable Poly objects. They also can be assigned in Face, Polygon, and Element subobject modes using a little rollout section called Edit Vertex Colors. Within this section are two color swatches for selecting Color and Illumination values. The Alpha value sets the alpha transparency value for the vertex.

Another, more interactive way to color vertices is with the Vertex Paint modifier. This modifier lets you paint on an object by specifying a color for each vertex. If adjacent vertices have different colors assigned, then a gradient is created across the face. The benefit of this coloring option is that it is very efficient and requires almost no memory.

The Vertex Paint modifier lets you specify a color and paint directly on the surface of an object by painting the vertices. The color is applied with a paintbrush-shaped cursor. The modifier can be applied multiple times to an object, giving you the ability to blend several layers of vertex paints together. You can find this modifier in the Modifiers

Applying this modifier opens a VertexPaint dialog box called the Paintbox, shown in Figure 16.9. At the top of the Paintbox are four icons that can be used to show the visible results of the painting in the viewports. The options include Vertex Color Display–Unshaded, Vertex Color Display–Shaded, Disable Vertex Color Display, and Toggle Texture Display On/Off.

The Vertex Color icon flyout lets you work on the Vertex Color, Illumination, Alpha, or any one of the 99 available map channels. The lock icon locks the display to the selected channel, or you could be looking at a different channel from the one you are painting.

The large Paint and Erase buttons let you add or remove vertex colors using the color specified in the color swatch. You can also select colors from objects in the viewports using the eyedropper tool and then set the Opacity.

The Size value determines the size of the brush used to paint. Max supports pressure-sensitive devices such as a graphics tablet, and you can set the brush options using the Brush Options dialog box. When paining on the surface of an object, a blue normal line appears. This line guides you as you paint so that you know you're on the correct surface.

Beneath the Brush Options button is a Palette button that opens the Color Palette interface, shown in Figure 16.10. The Color Palette holds custom colors and lets you copy and paste colors between the different swatches. Collections of colors can be saved by right-clicking the Color Palette and selecting the Save As command. Color palettes are saved as Color Clipboard files with the .ccb extension.

Figure 16.9. The Paintbox palette for the Vertex Paint modifier includes a wealth of features.

The Paintbox also includes three subobject selection icons. These icons can be used to select certain Vertices, Faces, or Elements to be painted. This limits the painting to the selected subobjects only. You also can select to Ignore Backfacing and use Soft Selection.

The Blur brush button lets you blur colors across polygons using a brush that works just like the Paint and Erase brushes.

The Adjust Color dialog box lets you change all the painted colors applied to an object using HSV or RGB color sliders. The Preview option makes the color adjustment visible in the viewports if selected. Below the Adjust Color icon is the Blur Selected icon that blurs together all the vertex colors based on the designated Amount value.

Colors can be mixed between layers using the various blending modes. Clicking the New Layer button adds a new instance of the Vertex Paint modifier to the Modifier Stack; the Delete Layer button does the opposite. Click the Condense to a Single Layer button to merge all the consecutive Vertex Paint modifiers to a single instance using the selected blending mode.

Figure 16.10. The Color Palette can display colors as a list or as swatches.

As an example of using the Vertex Paint modifier, imagine a doctor who has a 3D model of the human heart. While discussing the results of the latest test with a patient, the doctor can color parts of the heart model to illustrate the various points.

To color on a human heart using the Vertex Paint modifier, follow these steps:

Figure 16.11 shows the resulting color.

The Assign Vertex Color utility works a little differently. It converts any existing material colors to vertex colors. To use this utility, select the utility from the Utilities list that opens when the More button in the Utility panel is clicked, select an object, choose a Channel, choose a Light Model (Lighting + Diffuse, Lighting Only, or Diffuse Only), and click the Assign to Selected button.

Figure 16.11. The Vertex Paint modifier can apply color to an object by assigning a color to its vertices.