Working with Hair

Applying hair to an object is as easy as selecting an object and choosing the Hair and Fur WSM modifier, which is found in the Modifiers Hair and Fur Hair and Fur WSM. After hair is applied to an object, you can use the parameters in the Modify panel to change the hair's properties.

Growing hair

Hair can be grown on any geometry surface, including splines, by simply applying the Hair and Fur WSM to the selected object. When the Hair and Fur modifier is first applied to an object, it is applied to the entire surface of the selected object and when it is applied to set of splines, the hair appears between the first and last spline.

If you want to localize the hair growth to a specific area of the object, you can make a subobject selection using the controls in the Selection rollout. The available subobjects include Face, Polygon, Element, and Guides. After making a subobject selection, click the Update Selection to display the guide hairs only in the selected area in the viewports. Figure 19.1 shows hair grown on a man's face to create a beard.

Figure 19.1: By making a subobject selection, you can control precisely where hair is grown.

Tip 

After taking the time to make a subobject selection, create a selection set for the hair area for quick recall.

NEW FEATURE 

The Guides subobject is new in 3ds Max 9.

Applying hair to a single spline doesn't create any hair, but if multiple splines are included as part of the same Editable Spline object, then the hair is interpolated between the various splines in the order they are attached following the spline's curvature. This provides a great way to add special features like a ringlet to an existing set of hair.

Setting hair properties

Several rollouts of properties can be used to change the look of the hair. The General Parameters rollout, shown in Figure 19.2, includes settings for the overall Hair Count, the number of Hair Segments between adjacent splines, the number of Hair Passes, Density, Scale, Cut Length, Random Scale, Root and Tip Thickness, and Displacement. The Hair Count value sets the total number of hairs for the given geometry. Higher values take longer to render but produce more realistic hair. The Hair Passes sets the number of render passes to use for determining hair transparency. The higher the Hair Passes value, the more wispy the hair looks. The Rand Scale value provides a random amount of scaling for a percentage of hairs to look more natural. The Displacement value sets how far from the source object the hairs grow and can be a negative value.

Figure 19.2: Hair properties can be altered using the General and Material Parameters rollouts.

Caution 

Although the Hair Count value can accept huge numbers, adding a large number of hairs takes a long time to render and can really slow your system.

By making a subobject selection, you can control precisely where hair is grown.

The buttons to the right of most of the parameters in the General Parameters rollout lets you add a map to control the property with a grayscale bitmap. Figure 19.3 shows a simple plane object mapped with a bitmap used to control the hair density. The black areas of the bitmap have no hair growth, but the white areas have maximum growth. This provides a way to create patchy hair on a character or creature.

Figure 19.3: Many of the hair properties can be defined using maps

The Material Parameters rollout, also shown in Figure 19.2, includes settings for the Occluded Ambient value, controlling the tip and root colors, Hue and Value Variations, the addition of mutant hairs, percentage to include, and specular and glossiness settings. The Occluded Ambient value sets the contrast for the hair lighting. Smaller values have a stronger contrast, and higher values appear more washed out. The Hue and Value Variation values define a percentage that the hair color can deviate from the specified color to give the hair a more natural coloring. The Mutant percentage defines the percentage and color of hairs that are discolored, such as white hairs.

The Tip Fade option causes the hair to be more transparent toward the tip. The Specular Tint color changes the color of specular highlights. The Tip Fade and Specular Tint options apply only to hairs rendered with mental ray. The Self Shadow value sets how much the individual hairs cast shadows on other hairs, and the Geometry Shadow settings determines how much shadow is contributed by other geometry objects. The Geometry Material ID is used to assign a material to geometry-rendered hair.

NEW FEATURE 

The Tip Fade and Specular Tint settings are new in 3ds Max 9.

Many of the properties in the Material Parameters rollout also can be controlled using map buttons located to the right.

Caution 

Map colors are multiplied with the base color value, so set the base color to white before using a map.

In addition to the general and material parameters, rollouts also are available for controlling the amount of Frizz and Kink, and for the Multi-Strand nature of hair. Frizz causes the hair to curl at its tip or root. Kink parameters cause the hair to be zigzagged in shape; the Multi-Strand parameters cause hair to separate into groups like grass does. Figure 19.4 shows four areas with different hair properties applied, including normal straight hair with no frizz or kink, a section with Frizz, one with Kink, and Multi-Strand.

Figure 19.4: Changing hair properties can drastically alter the hair's look from normal to frizz, kink, and multi-strand

Tutorial: Adding a spline fringe to a quilt

Quilts are designed to make you feel all warm and fuzzy, and what could be fuzzier than some soft fringe surrounding a quilt. Fringe makes grabbing the quilt easy.

To add hairy fringe to a quilt using splines, follow these steps:

1. Open the  Patch quilt.max file from the Chap 19 directory on the DVD.

2. Select the Create Shapes Line menu command, and draw a simple spline that extends at right angles from every corner of the quilt in the Top view. Start at one corner, and proceed in turn clockwise around each of the corners. Add a second line on top of the first line to complete the set of splines.

3. Select the first spline, and convert it to an Editable Spline object using the right-click quadmenu. Then click the Attach button, and select the splines in the order they were created.

4. With all the splines selected, choose the Modifiers Hair and Fur Hair and Fur WSM menu command to apply the Hair and Fur modifier to the splines.

5. Open the Modify panel, and in the General Parameters rollout, set the Random Scale value to 10, and the Tip and Root Thickness to 5.0. Then open the Material Parameters rollout, and change the Tip and Root colors to white.

Figure 19.5 shows the resulting quilt with its fringe, all warm and fuzzy.

Figure 19.5: Hair can be added to only a subobject selection or to the entire object