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408 Chapter 13 ■ Introduction to Modeling with MilkShape

Table 13.18 UVMapper Edit Menu

Each of these methods is described in more detail here. Sometimes, even when you know exactly what the unwrapping method is supposed to do, you will be surprised at the results, so don't be afraid to experiment. Once you've loaded a model, you can keep trying the different unwrapping methods with different settings. Each time you do it, the program begins from scratch, so you don't have to worry about undoing your previous efforts.

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Figure 13.25 The Box

Mapping dialog box.

Figure 13.26 The Cylindrical

Mapping dialog box.

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410 Chapter 13 ■ Introduction to Modeling with MilkShape

Cylindrical Cap

When you use the Cylindrical Cap method, you will be presented with the dialog box depicted in Figure 13.27. Table 13.24 provides details about using the Cylindrical Cap method. This method is similar to the Cylindrical method, except that it assumes you are unwrapping a cylinder with end caps, as if there were closed lids on both ends of a can. The caps are mapped separately from the tubing of the cylinder.

Figure 13.27 The Cylindrical

Cap Mapping dialog box.

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412 Chapter 13 ■ Introduction to Modeling with MilkShape

Table 13.24 Cylindrical Cap Mapping Options

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UVMapper 413

Spherical

When you use the Spherical method, you will be presented with the dialog box depicted in Figure 13.28. You can get more information on using the Spherical method in Table 13.25.

Spread facets at poles Oftentimes facets are squeezed together when the mapping occurs, especially at places like the "poles" (the tops and bottoms of the map, just like on maps of the Earth). With this option set, the resulting map will spread the facets at the poles to alleviate the pinching effect.

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414 Chapter 13 ■ Introduction to Modeling with MilkShape

Moving Right Along

Well, there you have two pretty comprehensive, low-cost modeling tools: MilkShape 3D by Mete Ciragan and UVMapper by Steve Cox. These guys have done an admirable job creating these programs in the shareware or freeware spirit. They deserve not only a round of applause and big thank you, but you could also perhaps send a few dollars their way by registering their shareware programs. The cost is minuscule, and the benefits are great.

By using the common Wavefront file format, we can use each tool in complementary ways to create models for our games. This is a pretty common theme; notice also that we've used Paint Shop Pro—another low-cost tool—in the same way in conjunction with MilkShape. In the next few chapters we will tackle the Big Jobs: animated characters, vehicles, and weapons. It would not be wasted effort if you wanted to take some time out at this point to practice by designing and building some models to your own specifications.

The more you use a tool, make mistakes, and figure out what you did wrong and then make any necessary corrections on your own, the more proficient you will become.

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chapter 14

Making a

Character Model

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416Chapter 14 ■ Making a Character Model

together to create shapes that grow in size and detail. The clay can be poked and prodded, smoothed and pinched until it accurately depicts the item being modeled.

With Incremental Polygon Construction, the process is similar: We apply vertices in 3D space that represent high points and low points of the features to be modeled, and then we build triangles or faces connecting these vertices. One point of departure from clay modeling is that we typically don't add faces on top of (such that they completely obscure) other faces, because we have no need for a solid to give us the required volume. But the principle of adding faces to the existing topology of a model as the model grows is the same, as is the useful concept that we add only what we need, and no more.

The best way to get started with modeling in this way is to use photographs or sketches of the target from several directions: from directly in front, directly above, and one or both sides. From the pictures we can obtain the locations and shapes of the features and their high and low points. We mark these points in our 3D views, and then we proceed to build faces from them.

This technique can be quite slow going. It is also prone to errors that are difficult to correct, because you may have moved dozens of steps beyond where the real error occurred before the error becomes evident.

Axial Extrusion

In the simplest sense, you start with a primitive object (usually a box, but it could be a simple facet or triangle), subdivide it, and then select specific polygons to extrude into meshes to form general shapes. When you subdivide objects, you increase the number of polygons on each side of the shape. You then adjust and refine the extruded polygons to form the details of the model. This approach is similar to making models of geographic terrain using a contour map as a guide, with cardboard or plywood sheets to build up the terrain, and then smoothing the edges with some kind of filler.

With Axial Extrusion, you limit your extrusions to one of the three axes— sometimes all three in various combinations—but individual extrusion only occurs in one axis. This technique is usually restricted to inanimate objects, but sometimes certain parts of character models are made this way.

One example of using axial intrusion in character modeling is when creating a head. A series of flat-plane profiles (called cuts) are made of a head, after which each profile is extruded once in each direction on the transverse axis (the axis that runs from ear to ear). Then each extruded mesh is married to the extruded meshes of the adjacent cuts by an averaging of the vertices. You'll actually get to do some of these extrusions later in this chapter, and others.

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Arbitrary Extrusion

Arbitrary Extrusion has much in common with Axial Extrusion, except that you extrude your base primitive shapes in whatever directions are necessary. Like Incremental Polygon Construction, this approach to modeling can be seen as similar to sculpting in clay. Machinery lends itself well to modeling with this technique.

Topographical Shape Mapping

Topographical Shape Mapping is a method usually used to model terrain, like Axial Extrusion often is, except that Topographical Shape Mapping is best suited for automated operations rather than manually modeling.

In the geographic sense, topographic data can be obtained from various government and private sources. The data consists of, at a minimum, a coordinate and an altitude for each mapped point on the real terrain's surface. There are various algorithms and many programs available that can read this data from a file and render a 3D view of the terrain in question. The data files come in various formats depending on the agency that produces them: DLG-O, DEM, SDTS, and DRG, to name just a few from that acronymic world. Normally this approach is used in one of the many available Geographic Information Systems (GIS), and there are tools that can convert this data into a format you can use for modeling in games.

Hybrids

Well, the Hybrid category is the catchall category. Often it is prudent to combine techniques in a single model—use the approach that works best for the component being created. If you find yourself mixing techniques, most likely you will be doing a little bit of Incremental Polygon Construction mixed with many shape primitives or using a few primitives mixed with a great deal of Arbitrary Extrusion.

The best point to be made here is that you should use what works best for you in your current circumstances.

The Base Hero Model

The technique we are going to use is basically the Shape Primitives approach. We will hand-modify various shape primitives to get the results we want.

The kind of model we are going to make is primarily a segmented-mesh model. An alternative would be a continuous-mesh model. The difference is that in the segmented-mesh model, there are different, distinct objects or meshes for different components in the model, whereas in the continuous-mesh model, the entire model has one large, convoluted surface. Our primary segments will be as follows:

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