Chapter 13: Learning Modeling Basics and Working with Subobjects

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 introduces the various modeling methods in Max. It also explains the common modeling components, including normals and subobjects. The chapter also covers many utilities and helpers that, well, help as you begin to model objects. The purpose of this chapter is to whet your whistle for modeling and to cover some of the general concepts that apply to all models. More specific details on the various modeling types are presented in the subsequent chapters, so onward into the realm of creation.

Exploring the Model 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.

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, Edit Poly, and Edit Spline.

Max includes the following model 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 6, "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 14, "Drawing and Editing 2D Splines and Shapes."
Polys: Objects composed of polygon faces, similar to mesh objects, but with unique features. These objects are also available only as Editable Poly objects. Poly objects are covered together in Chapter 15, "Modeling with Polygons."
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. Meshes are also covered in Chapter 15.
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 17, "Modeling with Patches and NURBS," 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 17, "Modeling with Patches and NURBS."
Compound objects: A miscellaneous group of model 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 18, "Working with Compound Objects."
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 Particle Flow interface in Chapter 35, "Creating Particles and Particle Flow."
Hair and fur: Modeling hundreds of thousands of cylinder objects to create believable hair would quickly bog down any system, so hair is modeled using a separate system that represents each hair as a spline. The Hair and Fur modifiers are covered in Chapter 19, "Adding and Styling Hair, Fur, and Cloth."
Cloth systems: Cloth-with its waving, free-flowing nature-behaves like water in some cases and like a solid in others. Max includes a specialized set of modifiers for handling cloth systems. Creating and using a cloth system is discussed in Chapter 19, "Adding and Styling Hair, Fur, and Cloth."

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 sub-categories 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 popup 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 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.

Converting between object types is done automatically using Max's best guess, but if you apply one of the Conversion modifiers to an object, several parameters are displayed that let you define how the object is converted. For example, the Turn to Mesh modifier includes an option to Use Invisible Edges, which divides polygons using invisible edges. If this option is disabled, then the entire object is triangulated. The Turn to Patch modifier includes an option to make quads into quad patches. If this option is disabled, all quads are triangulated.

The Turn to Poly modifier includes options to Keep Polygons Convex, Limit Polygon Size, Require Planar Polygons, and Remove Mid-Edge Vertices. The Keep Polygons Convex option divides any polygon that is concave, if enabled. The Limit Polygon Size option lets you specify the maximum allowable polygon size. This can be used to eliminate any pentagons and hexagons from the mesh. The Require Planar Polygons option keeps adjacent polygons as triangles if the angle between them is greater than the specified Threshold value. The Remove Mid-Edge Vertices option removes any vertices caused by intersections with invisible edges.

All Conversion modifiers also include options to preserve the current subobject selection (including any soft selection) and to specify the Selection Level. The From Pipeline option uses the current subobject selection that is selected on the given object. After a Conversion modifier is applied to an object, you must collapse the Modifier Stack in order to complete the conversion.