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The Displacement Approximation (or Disp Approx) modifier makes displacement mapping (which is applied using materials) available in the Modifier Stack. This modifier alters the surface of an object based on displacement mapping. This modifier can work with any object that can be converted to an Editable Mesh, including primitives, NURBS, and Patches. Parameters for this modifier include Subdivision Preset settings of Low, Medium, and High.

The Displace NURBS World-Space modifier is similar to the Disp Approx modifier. It can convert a NURBS object into a mesh object and includes the effect of a displacement map. In the Displace NURBS rollout, you can select the Tessellation method to be Regular, Parametric, Curvature, Spatial, or both.

Summary

NURBS are an ideal method for modeling if you require free-flowing models. In this chapter, you’ve

Created CV and point curves

Discovered how to convert primitives to NURBS objects

Created NURBS surfaces from curves

Learned to edit NURBS curves and surfaces

Used NURBS subobject tools

Lofted surfaces from point and CV curves

Created NURBS surfaces by lathing and sweeping

The next chapter focuses on working with a miscellaneous group of mutant objects called compound objects. These objects are unique and used for special purposes.

Building Compound

Objects

So far, we have covered a variety of modeling types, including shapes, meshes, polys, patches, and NURBS. The Compound

Objects subcategory includes several additional modeling types that don’t seem to fit anywhere else. As you will see in this chapter, these modeling types provide several new and unique ways to model objects, such as working with Boolean objects, scattering objects across the surface of another object, or lofting a cross section along a spline path.

Understanding Compound

Object Types

The Compound Objects subcategory includes several unique object types. You can access these object types with the Create Compound menu or by clicking the Geometry category button in the Create panel and selecting Compound Objects in the subcategory drop-down list. All the object types included in the Compound Objects subcategory are displayed as buttons at the top of the Create panel. They include the following:

Morph: Consists of two or more objects with the same number of vertices. The vertices are interpolated from one object to the other over several frames.

Scatter: Randomly scatters a source object about the scene. You can also select a Distribution object that defines the volume or surface where the objects scatter.

Conform: Wraps the vertices of one object onto another. You can use this option to simulate a morph between objects with different numbers of vertices.

Connect: Connects two objects with open faces by joining the holes with additional faces.

BlobMesh: Creates a metaball object that flows from one object to the next like water.

17C H A P T E R

In This Chapter

Understanding compound objects

Morphing objects

Using the Conform and ShapeMerge compound objects

Creating Terrain objects

Using the Mesher object

Using the Scatter and Connect compound objects

Working with

BlobMesh objects

Creating Boolean objects

Lofting objects

Deforming lofted objects

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ShapeMerge: Lets you embed a spline into a mesh object or subtract the area of a spline from a mesh object.

Boolean: Created by performing Boolean operations on two or more overlapping objects. The operations include Union, Subtraction, Intersection, and Cut.

Terrain: Creates terrains from the elevation contour lines like those found on topographical maps.

Loft: Sweeps a cross-section shape along a spline path.

Mesher: Creates an object that converts particle systems into mesh objects as the frames progress. This makes assigning modifiers to particle systems possible.

Note When two or more objects are combined into a single compound objects, they use a single object material. The Multi/Subobject material type can be used to apply different materials to the various parts.

Morphing Objects

Morph objects are used to create a Morph animation by interpolating the vertices in one object to the vertex positions of a second object. The original object is called the Base object, and the second object is called the Target object. The Base and Target objects must have the same number of vertices. One Base object can be morphed into several targets.

Caution	To ensure that the Base and Target objects have the same number of vertices, create a copy
	of one object and modify it to be a target. Be sure to avoid such modifiers as Tessellate and
	Optimize, which change the number of vertices.

To morph a Base object into a Target, select the Base object and select Create --Compound Morph. Then click the Pick Target button in the Pick Targets rollout, shown in Figure 17-1, and select a Target object in the viewport. The cursor changes to a plus sign when it is over an acceptable object. Unavailable objects (that have a different number of vertices) cannot be selected. Pick Target options include Copy, Instance, Reference, and Move. (The Move option deletes the original object that is selected.) The Target object appears under the Current Targets rollout in the Morph Targets list.

Each Morph object can have several Target objects. You can use the Pick Target button to select several targets, and the order in which these targets appear in the list is the order in which they are morphed. To delete a Target object, select it from the list and click the Delete Morph Target button. Beneath the list is a Name field where you can change the name of the selected Target object.

Creating Morph keys

With a Target object name selected in the Morph Targets list, you can drag the Time Slider to a frame and set a Morph key by clicking the Create Morph Key button found at the bottom of the rollout. This option sets the number of frames used to interpolate among the different morph states.

Chapter 17 Building Compound Objects 475

Figure 17-1: A Morph rollout lets you pick targets and create morph keys.

Note If the Morph object changes dramatically, set the Morph Keys to include enough frames to interpolate smoothly.

If a frame other than 0 is selected when a Target object is picked, a Morph Key is automatically created.

Morph objects versus the Morph modifier

Max includes two different ways to morph an object. You can create a Morph object or apply the Morph modifier to an existing object. The Morph object is different from the Morph modifier, but the results are the same; however, some subtle differences exist between these two.

A Morph object can include multiple Morph targets, but it can be created only once. Each target can have several Morph keys, which makes it easy to control. For example, you could set an object to morph to a different shape and return to its original form with only two Morph keys.

The Morph modifier, on the other hand, can be applied multiple times and works well with other modifiers, but the control for each modifier is buried in the Stack. The Parameters rollout options available for the Morph modifier are much more extensive than for the Morph object, and they include channels and support for a Morph material.

Cross-	You can find more information on the Morph modifier in Chapter 30, “Animation Basics.”
Reference

For the best of both worlds, apply the Morph modifier to a Morph object.

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Tutorial: Morphing a woman’s face

Although this example is fairly simple, it demonstrates a powerful technique that can be very helpful as you begin to animate characters. One of the key uses of morphing is to copy a character and move it about to create a new pose. You can then morph between the different poses to create smooth actions, gestures, or face motions.

To morph a woman’s face, follow these steps:

1.Open the Greek woman head morph.max file from the Chap 17 directory on the CD-ROM.

This file includes a woman’s head. All objects have been attached to the face object to make it easy to work with.

2.Select the head object and hold down the Shift key while dragging to the right in the Top viewport. In the Clone Options dialog box that opens, select Copy and set the Number of Copies to 2. Name one copy frown face and the other smiling face.

3.Select the object named “smiling face,” and open the Modify panel. Zoom in around the mouth area, and enable the Vertex subobject mode. Enable the Ignore Backfacing option in the Selection rollout, and turn on the Use Soft Selection option in the Soft Selection rollout with a Falloff value of 1.4. Then select the vertex at the corner of the mouth, and drag it upward in the Front viewport to make the woman smile. Repeat this action for the vertex on the opposite side of the mouth. Click on the Vertex subobject button again to exit subobject mode.

4.Select the original head object, and choose Create Compound Morph to make this object into a morph object. In the Pick Targets rollout, select the Copy option and click the Pick Target button. Then click the “frown face” object, or press the H key, and select it from the Select Objects dialog box (actually, it is the only object that you can select). Then click the “smiling face” object. Both targets are now added to the list. Click the Pick Target button again to disable pick mode.

5.In the Morph Targets list, select the “frown face” object and click the Create Morph Target button. Then drag the Time Slider (below the viewports) to frame 50, select the “smiling face” object, and press the Create Morph Key button again.

6.Click the Play button (in the Time Controls section at the bottom of the Max window) to see the morph.

The woman’s head object morphs when you move the Time Slider between frame 0 and 50. Figure 17-2 shows different stages of the morph object.

Figure 17-2: A woman’s face being morphed to a smile