482 Part III Modeling

5.Now select the letter B in the logo name, and click the ShapeMerge button again. Use the Pick Shape button and the Cookie Cutter operation option to remove the centers of this letter. Click the Select Object button on the main toolbar to exit ShapeMerge mode. Repeat this step for each of the letters that has an interior portion, including the following letters: g, e, a, d, o, a, and e.

6.Open the Display panel again, and in the Hide rollout, click Unhide All to redisplay the interior splines of the letter B that make up the bug’s left eye. Hold down the Ctrl key, select the two splines, choose Modifiers Mesh Editing Extrude, and enter an Amount value of 0.0.

Figure 17-7 shows the finished logo. Notice that the letters have the interior sections removed.

Figure 17-7: The logo with the interior centers removed from extruded letters using the ShapeMerge object

Creating a Terrain Object

The Terrain object is a great object that enables you to create terrains from splines representing elevation contours. These contour splines can be created in Max or imported using a format like AutoCAD’s DWG. If the splines are created in Max, make sure that they are attached to each other as one object, in the order in which they will eventually be attached. The splines all need to be closed splines.

Chapter 17 Building Compound Objects 483

To create a terrain, create splines at varying elevations, select all the splines, and click the Terrain button. You can use the Pick Operand button in the Pick Operand rollout to select additional splines to add to the Terrain object. All splines in the object become operands and are displayed in the Operands list.

The Form group includes three options that determine how the terrain is formed: Graded Surface, Graded Solid, and Layered Solid. The Graded Surface option displays a surface grid over the contour splines; the Graded Solid adds a bottom to the object; and the Layered Solid displays each contour as a flat, terraced area.

The Display group includes options to display the Terrain mesh, the Contour lines, or Both. You can also specify how you want to update the terrain.

The Simplification rollout lets you alter the resolution of the terrain by selecting how many vertical and horizontal vertices to use. Options include using all vertices, half of the vertices, a quarter of the vertices, twice the vertices, or four times the vertices.

Coloring elevations

The Color by Elevation rollout, shown in Figure 17-8, displays as reference the Maximum and Minimum Elevations. Between these is a Reference Elevation value, which is the location where the landmass meets the water. Entering a Reference Elevation and clicking the Create Defaults button automatically creates several separate color zones. You can add, modify, or delete zones using the Add, Modify, or Delete Zone buttons.

You can access each color zone from a list. To change a zone’s color, select it and click the color swatch. You can set colors to Blend to the Color Above or to be Solid to Top of Zone.

Tutorial: Creating an island with the Terrain compound object

In this tutorial, we create a simple island. The Color by Elevation rollout makes distinguishing the water from the land easy.

Figure 17-8: The Color by Elevation rollout lets you change the color for different elevations.

484 Part III Modeling

To create an island using the Terrain object, follow these steps:

1.Select Create Shapes Ellipse and drag in the Top view to create several ellipses of various sizes representing the contours of the island. The first ellipse you create should be the largest, and they should get progressively smaller.

2.In the Left view, select and move the ellipses up and down so that the largest one is on the bottom and the smallest one is on top. You can create two smaller hills by including two ellipses at the same level.

3.Use the Edit Select All (Ctrl+A) menu command to select all the ellipses, and select Create Compound Terrain.

The ellipses automatically join together. Joining all the ellipses forms the island.

4.In the Color by Elevation rollout, select a Reference Elevation of 5 and click the Create Defaults button.

This automatically creates color zones for the island. The elevation values for each zone are displayed in a list within the Color by Elevation rollout. Selecting an elevation value in the list displays its color in the color swatch.

5.Select each elevation value individually, and set all Zones to Blend to the Color Above option for all zones, except for the Zone with the lightest blue.

This creates a distinct break between the sea and the land of the island.

Figure 17-9 shows the final terrain. In an example later in this chapter, we use the Scatter compound object to add trees to the small terrain island.

Figure 17-9: A Terrain island created with the Terrain compound object

Chapter 17 Building Compound Objects 485

Using the Mesher Object

You can use the Mesher compound object to convert objects to mesh objects on the fly as an animation progresses. This feature is useful for objects such as particle systems. After you convert the object to a mesh object, you can apply modifiers that weren’t possible before, such as Optimize, UVW Map, and others.

Another benefit of the Mesher object is that you can apply several complex modifiers to a single Mesher object and tie it to a particle system rather than applying the modifiers to all the pieces that make up a particle system.

The Parameters rollout of the Mesher object includes a Pick Object button. Click this button, and select an object in the viewport to make the selected object an instance of the Mesher object. This action does not delete the original object, and the Mesher instance is oriented to the Mesher object’s coordinate system. The object name then appears on the button. You can change the object by clicking the button again and selecting a new object.

Caution	Do not delete the original object, or the Mesher instance also disappears. If you want to
	render only the Mesher instance, then select the original object and hide it using the Tools
	Display Floater command.

The Time Offset is the number of the frames ahead (values can be negative) or behind the original object the animation should progress. If the Build Only at Render Time option is set, then the Mesher instance is not visible in the viewports but shows up in the final rendered image. You can use the Update button to manually force an update of the Mesher instance after the settings for the original object have been modified.

When you use the Mesher object to create an instance of a particle system, the bounding box of the particle system as it streams the particles becomes long and thin over time. This long and thin bounding box can potentially cause problems with certain modifiers. You can prevent these problems by selecting an alternative bounding box that doesn’t change over time. To select a new bounding box, select the Custom Bounding Box option, click the Pick Bounding Box button, and click an object in the viewport. You can select the original object as the new bounding box. With the Mesher object selected, the bounding box is shown in orange wherever it is located. The corner coordinates of the custom bounding box are displayed under the Pick Bounding Box button.

Note	Mesher objects can also be used as Particle Flow events using the Add and Remove buttons
	at the bottom of the Parameters rollout.

Figure 17-10 shows a Super Spray particle system on the right and its Mesher instance with the Bend modifier applied on the left.

Cross-	Chapter 18, “Creating Particles and Particle Flow,” provides more information on working
Reference	with particle systems.