Modeling Basics

Modeling is the process of pure creation. Whether it is sculpting, building with blocks, construction work, carving, architecture, or advanced injection molding, many different ways exist for creating

objects. Max includes many different model types and even more ways to work with these model types.

This chapter gives you the scoop on modeling in Max and introduces you to many utilities and helpers that, well, help as you begin to model objects.

Exploring the Modeling Types

You can climb a mountain in many ways, and you can model one in many ways. You can make a mountain model out of primitive objects like blocks, cubes, and spheres, or you can create one as a polygon mesh. As your experience grows, you discover that some objects are easier to model using one method and some are easier using another. Max offers several different modeling types to handle various modeling situations.

Parametric objects versus editable objects

All geometric objects in Max can be divided into two general categories — parametric objects and editable objects. Parametric means that the geometry of the object is controlled by variables called parameters. Modifying these parameters modifies the geometry of the object. This powerful concept gives parametric objects lots of flexibility. For example, the sphere object has a parameter called Radius. Changing this parameter changes the size of the sphere. Parametric objects in Max include all the objects found in the Create menu.

Editable objects do not have this flexibility of parameters, but they deal with subobjects and editing functions. The editable objects include Editable Spline, Mesh, Poly, Patch, and NURBS. Editable objects are listed in the Modifier Stack with the word Editable in front of their base object (except for NURBS objects, which are simply called NURBS Surfaces). For example, an editable mesh object is listed as Editable Mesh in the Modifier Stack.

12C H A P T E R

In This Chapter

Understanding the modeling types

Working with subobjects and soft selections

Using helper objects

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Note Actually, NURBS objects are a different beast altogether. When created using the Create menu, they are parametric objects, but after you select the Modify panel, they are editable objects with a host of subobject modes and editing functions.

Editable objects aren’t created; instead, they are converted or modified from another object. When a primitive object is converted to a different object type like an Editable Mesh or a NURBS object, it loses its parametric nature and can no longer be changed by altering its base parameters. Editable objects do have their advantages, though. You can edit subobjects such as vertices, edges, and faces of meshes — all things that you cannot edit for a parametric object. Each editable object type has a host of functions that are specific to its type. These functions are discussed in the coming chapters.

Note Several modifiers enable you to edit subobjects while maintaining the parametric nature of an object. These include Edit Patch, Edit Mesh, and Edit Spline.

Max includes the following modeling types:

Primitives: Basic parametric objects such as cubes, spheres, and pyramids. The primitives are divided into two groups consisting of Standard and Extended Primitives. The AEC Objects are also considered primitive objects. A complete list of primitives is covered in Chapter 5, “Creating and Editing Primitive Objects.”

Shapes and splines: Simple vector shapes such as circles, stars, arcs and text, and splines such as the Helix. These objects are fully renderable. The Create menu includes many parametric shapes and splines. These parametric objects can be converted to Editable Spline objects for more editing. These are covered in Chapter 13, “Drawing and Editing 2D Splines and Shapes.”

Meshes: Complex models created from many polygon faces that are smoothed together when the object is rendered. These objects are available only as Editable Mesh objects.

Polys: Objects composed of polygon faces, similar to mesh objects, but with unique features. These objects are also available only as Editable Poly objects. Mesh and Poly objects are covered together in Chapter 14, “Working with Meshes and Polys.”

Patches: Based on spline curves; patches can be modified using control points. The Create menu includes two parametric Patch objects, but most objects can also be converted to Editable Patch objects. Chapter 15, “Creating and Editing Patches,” covers patches in detail.

NURBS: Stands for Non-Uniform Rational B-Splines. NURBS are similar to patches in that they also have control points. These control points define how a surface spreads over curves. NURBS are covered in Chapter 16, “Working with NURBS.”

Compound objects: A miscellaneous group of modeling types, including Booleans, loft objects, and scatter objects. Other compound objects are good at modeling one specialized type of object such as Terrain or BlobMesh objects. All the Compound objects are covered in Chapter 17, “Building Compound Objects.”

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Particle systems: Systems of small objects that work together as a single group. They are useful for creating effects such as rain, snow, and sparks. Particles are covered along with the new Particle Flow interface in Chapter 18, “Creating Particles and Particle Flow.”

With all these options, modeling in Max can be intimidating, but you learn how to use each of these types the more you work with Max. For starters, begin with primitive or imported objects and then branch out by converting to editable objects. A single Max scene can include multiple object types.

Converting to editable objects

Of all the commands found in the Create menu and in the Create panel, you won’t find any menus or subcategories for creating editable objects.

To create an editable object, you need to import it or convert it from another object type. You can convert objects by right-clicking on the object in the viewport and selecting the Convert To submenu from the pop-up Quadmenu, or by right-clicking on the base object in the Modifier Stack and selecting the object type to convert to in the pop-up menu. Once converted, all the editing features of the selected type are available in the Modify panel, but the object is no longer parametric.

Caution	If a modifier has been applied to an object, the Convert To menu option in the Modifier Stack
	pop-up menu is not available until you use the Collapse All command.

The pop-up menu includes options to convert to editable mesh, editable poly, editable patch, and sometimes NURBS. If a shape or spline object is selected, then the object can also be converted to an editable spline. Using any of the Convert To menu options collapses the Modifier Stack.

Note Objects can be converted between the different types several times, but each conversion may subdivide the object. Therefore, multiple conversions are not recommended.

Tutorial: Creating trumpet flowers with various modeling types

The best way to understand the different modeling types is to try them out. In this tutorial, we create a simple trumpet flower using several modeling types (if you don’t want to play with flowers, you can think of it as a piston in a car’s engine). Each modeling type has its benefits. This tutorial just scratches the surface of the modeling capabilities of each type, but it gives you an idea of what each type is like.

To create a trumpet flower using several different methods, follow these steps:

1.First we create a flower using the Editable Poly object. Select Create Standard Primitives Cylinder and drag in the Top viewport. Set the Radius to 40, the Height to 2.0, and the Cap Segments to 3.0. Right-click the Cylinder object and select Convert To Editable Poly from the pop-up Quadmenu.

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2.In the Modifier Stack, select the Vertex subobject mode and select the center vertex. In the Soft Selection rollout, click the Use Soft Selection option, set the Falloff to 285, and the Pinch value to 2.5. Then drag the selected vertex downward in the Left viewport.

3.Select the two middle rows of vertices in the Front viewport, disable the Soft Selection option, and scale the vertices down slightly to give flower a bend. Then enable the Use NURMS Subdivision option in the Subdivision Surfaces rollout and set the Iterations to 1. Click the Vertex subobject in the Modifier Stack to disable Vertex subobject mode.

4.Next, we create the same flower using patches. Select Create Standard Primitives Cylinder and drag in the Top viewport to create another Cylinder object using the same settings. Right-click on the Cylinder object and select Convert To Editable Patch from the pop-up Quadmenu.

5.From the Modifier Stack, select Vertex subobject mode. Then select the center vertex, enable Soft Selection with the same settings, and drag in the Left viewport. Disable the Lock Handles option in the Selection rollout, select the Handle subobject mode, and drag the handles for the bottom vertex upward in both the Front and Left viewports until they make a sharp point at the bottom of the flower.

6.For the NURBS version of the flower, select Create NURBS CV Curve and click in the Front viewport three times: at the bottom point of the flower, again about halfway up along the center axis, and again near the outer edge. These clicks form three control points that define the profile of the flower. Right-click to end the curve. Then right-click again on the curve and select Convert To Convert to NURBS from the pop-up menu.

7.In the NURBS Creation Toolbox palette of tools that appears, click Create Lathe Surface and select the NURBS curve in the Front viewport. Set the Degrees value in the Lathe Surface rollout to 360.

8.For the final flower, we use the Loft Compound object. Select Create Shapes Circle and create four circles centered about the same point in the Top viewport. Make their Radius values 1, 10, 20, and 40 respectively. Use the Select Objects dialog box (H) to select each circle in order and move it down in the Front viewport to its vertical position corresponding to the flower’s profile.

9.With the bottom circle selected, right-click and select Convert To Editable Spline in the pop-up Quadmenu. In the Geometry rollout, click Attach, select the other three circles in order, and right-click to exit attach mode. Then click Cross Section and select each of the circles in order from the bottom upward. Right-click after you’ve selected all the circles and again to exit Cross Section mode. Select Modifiers Patch/Spline Editing Surface to apply a surface to the spline cage and set the Patch Topology Steps value to 8.

Figure 12-1 shows the four different trumpet flowers. Notice how each modeling type is slightly different. Some look more organic, and others more mechanical. As you learn to use these modeling types, you’ll understand their differences.