Essential LightWave 3D- P11 pptx

16. Now, working with the curves that define the rubberized bumper and the opening on top of the kayak, select the curves in the order shown in Figure 13-16. Fill in the Make Spline Patch window with Perpendicular set to 10 segments distributed WRT Length (for a nice, soft feel to its silhouette) and Parallel set to 5 segments distrib - uted WRT Knots (so the bumper’s segments will line up perfectly with the segments of our kayak’s opening). 17. The resultant patch may look pretty angular as it skirts the rim of the kayak’s opening, but I’m planning on using this as a sub-patch model, so it’ll be fine. (Notice how the segments of the bumper and the opening line up perfectly.) Assign these polys a surface appropriate for a rubberized bumper, and copy and paste the bumper onto your assembly layer. Note Wouldn’t it be nice to be so brilliant that you know exactly what every setting does at every turn? I’m pretty far away from that myself. To get the above settings correct to match the bumper up with the kayak’s opening, just like anyone else, I had to play around with it a bit until I found the right settings. Still, I didn’t trust it just looking right. I tested it, copying both patches to a “junk” layer and using Merge Points to see if it fused the two sections together. No one’s perfect. Don’t bust your chops if you’re not. Chapter 13 ······················· 288 Figure 13-16 18. Selecting a few polys from the nose sections of our kayak and using Select Connected quickly selects all the polys we’ll need to mirror to become its tail. Mirror those polys across X=0. (You may merge points if you like. I don’t because I like to get the numeric info of just how many points were elimi - nated when I merge points manually.) Because our spline cage was created by mirroring, our patches should fit per - fectly by mirroring as well. ·············· Spline Modeling Exercise: Kayak 289 Figure 13-17 Figure 13-18 19. Mirror the entire kayak across Z=0, and then merge points. Chapter 13 ······················· 290 Figure 13-19 Figure 13-20: Our completed kayak, surfaced and viewed as sub-patches! That wasn’t so hard, was it? There are many applications where using spline patches can be pretty nifty. The hardest part about spline modeling in LightWave is juggling the settings in your mind so your patches end up seaming properly. (It’s a little like that children’s game of memory — but it’s not cheating if you want to use pencil and paper.) Just know that it may take a couple of tries to get things to line up. Also, remember that you’ve got to watch the distribution of your knots. You can do some pretty fancy tricks through creative placement of those little things. Be sure to weld all your endpoints. (This is a simple thing, but it still slips by me from time to time.) There you go. To quote Obi Wan Kenobi, “You’ve taken your first step into a larger world.” At the time of publication, only an estimated 4% of LightWave users said that they understood spline patch modeling. You can take pride in knowing that you’re actu - ally ahead of the pack! And to solidify your position there, we’re going to exercise your knowledge of splines by using them to model a human head. Flip the page and let’s begin! ·············· Spline Modeling Exercise: Kayak 291 Chapter 14 Spline Modeling Exercise 2: Modeling a Human Head Splines are a wonderful tool and I hope you’re beginning to see just how powerful they can be. Splines are most often used to model objects with large complex surface areas, such as vehicles and aircraft. In this chapter, we’ll be looking at a more esoteric use of splines, namely for the creation of a realistic human head model. This chapter will provide a detailed explanation of the process. It is a long chap- ter, but don’t let that intimidate you. Each step is broken down and discussed in detail, making it easy to follow, even for new users. That said, however, I expect you to have already worked through the previous modeling chapters and to have a basic understanding of the spline modeling rules outlined in Chapter 12. We’ll get into the actual modeling shortly, but first let’s talk about the things that make a good head model. 292 Figure 14-1: The head model built in this chapter with textures applied. Poly Count and Flo w I’ve seen hundreds of head models and doz - ens of tutorials showing how to build them. There are as many techniques for building a head as there are people building them. But regardless of how the head is constructed, there are two inherent qualities it must pos - sess in order for it to be “successful.” Contrary to what you might think, looking good is not one of them. Rather, the most successful head models are those with a reasonably low polygon count and an ideal polygon flow. Poly Count The best modelers are always striving to create their objects with the fewest number of polygons possible. This isn’t just an obsessive-compulsive drive. It’s a practical quest. The more polygons an object has, the longer it will take to render. Even with the most modern processors, a high-poly sub-patch object will hit the render engine harder than a low-poly object. But the quest for minimal polygons isn’t just about render time. It’s much more practical than that. You see, when you sub-patch an object, you are actually interpolating geometry between each point in your object. Take a look at Figure 14-2, which shows two sub-patched objects. The object on the left is a simple box with a single cut running down the center. Moving the points at the center of this box creates a smooth arc from one end of the object to the other. This arc is caused by the interpolation of geometry that occurs when an object is sub-patched. Now take a look at the object on the right. It is the same box, but in this case, there are six more cuts running through it. Moving the middle points on this object still results in an inter- polation of geometry; however, since the points on either side of those being moved are now closer together, the arc is tighter and more pronounced. Understanding this ···· Spline Modeling Exercise 2: Modeling a Human Head 293 Figure 14-2: Low poly count enables broader changes to your model. simple truth is the key to effective subpatch modeling. The more polygons you have in a given area, the more pronounced the effect on the movement of points in that area. Take a look at Figure 14-3. Keeping in mind what you saw in Figure 14-2, you can imagine what would happen if you moved the points on either of these objects. Undoubtedly, the object on the left would enable you to make broad changes (similar to the object on the left in Figure 14-2). Small movements to the points on this object would not have a drastic impact on its overall shape. That’s not true for the object on the right. Even minor adjust - ments to this object’s points would result in a noticeable change to its form. Learning to control the poly count and understanding where and when it’s appro - priate to add more geometry is a skill that takes time to develop. But suffice it to say that as you model, you should strive to keep your poly count as low as possible. Poly Flow The other quality that makes a good head model is proper polygon flow. Flow is a diffi- cult concept to grasp, especially for beginners. In essence, it is the deliberate layout of polygons into overlapping bands or loops that, when fully realized, mimic the natural flow of muscles under the skin. Keep in mind that as you model, you are simulating reality. Whether it’s a wineglass, a sports car, or a human being, you are building a simulation of a real-world object. In the case of organic models such as ani - mals and people, you are simulating the features that make up their outward appear - ance, typically muscle and bone. It is important, then, to study in great detail the forms you are attempting to simulate. Amazing character models aren’t created by accident. The best character modelers are those who have a solid grasp of human anatomy. Chapter 14 ······················· 294 Figure 14-3 ···· Spline Modeling Exercise 2: Modeling a Human Head 295 Figure 14-4: Basic muscle flow of the human head. Figure 14-5: Bad polygon flow (left) compared with good flow (right). Unfortunately, an introduction to anatomy is beyond the scope of this chapter, but I would encourage you to pick up an anatomy book or attend a figure drawing class if you intend to pursue character modeling. And I would strongly encourage you to visit http://www.fineart.sk and http://www.3d.sk. These two sites offer the most comprehen - sive set of resources for character modelers that you can find. The need for ideal polygon flow doesn’t stem from a purist compulsion. Like poly - gon count, it is a practical requirement. Consider this: Character models are rarely built to hold a single pose or a solitary facial expression (like Michelangelo’s sculpture of David). On the contrary, they are built to be animated and posed in a variety of fashions. A real face can make expressions (e.g., smiling or frowning) because of the layout of muscles in the face. Therefore, if your 3D model’s polygons do not mimic the flow of muscles in a real face, it will be difficult to create realistic expressions in a simulated face. You will find yourself fighting the model to get so much as a smirk. It becomes imperative, then, to build a model with great flow. In Chapter 10, we built a head model using the detail-out approach. The advan - tage to the detail-out approach is that it is a WYSIWYG process. You have immediate feedback on the model at each stage of development. The problem with the detail-out approach is that poly-by-poly con - struction makes it frustratingly difficult to develop good flow (especially for beginners) and it often yields objects with a high poly count. Spline modeling, however, avoids these pitfalls, allowing you to visualize the flow of your polygons and to selectively adjust the resolution of each patch for opti- mal poly count. Spline Modeling Pitfalls Spline modeling, while elegant and efficient, is not without its problems. As we’ve seen in previous chapters, there are rules that need to be followed. And even when the rules are followed, the occasional “Curves Do Not Cross” error will appear (seemingly for no reason at all). Moreover, spline mod - eling’s greatest strength can also be its biggest weakness, especially when dealing with organic models. While splines make it easy to visualize the flow of your polys, you must have a solid understanding of flow in the first place to build them correctly. You also have to be extremely careful when specifying your Perpendicular and Parallel patch settings to avoid creating polygons that do not line up properly from patch to patch. And as if all of that weren’t enough, the cold hard truth is that some objects are not well-suited for spline modeling. These drawbacks cause many modelers to steer clear of splines altogether. But you’re in luck — I’m going to show you several tricks to work around these pesky problems. Chapter 14 ······················· 296 Spline Modeling Tips and Tricks The major pitfalls of spline modeling can be avoided by following these simple tips and tricks. • Tip 1: Use splines for their strengths, not their weaknesses. It sounds obvious, but you’d be surprised at how many people don’t get this. Splines work best as a visual - ization tool, allowing you to establish the overall form of your object quickly and eas - ily. They do not work well for creating intricate details, but I see people attempting this all the time. They build spline cages with an incredible amount of detail and expect to simply patch it and be done. It sounds great in theory, but it rarely works out in practice. So rather than using splines as a be-all and end-all, use them for what they’re good for — namely building the overall form of your object. Then use the other tools at your disposal to model in the details. • Tip 2: Build quad cages. It’s best to build your cage so that every region is bounded by four splines. I call this a quad cage. It consists of splines for the top, bot - tom, left, and right for each area in your cage, both large and small. Building a quad cage is perhaps the most critical component of spline modeling, and I’ll be teaching you more about it as we proceed. • Tip 3: Use simple patches. One of the most time-consuming aspects of spline modeling is determining the proper Parallel and Perpendicular patch settings. Figuring this out is like some sort of twisted game. You have to remember which spline you selected first in order to establish how the perpendicular and parallel patches are con - structed. And then you have to ensure that the patches line up properly to those around them. It’s a hassle, but here’s a simple solu - tion: Use the same patch settings for the whole object. If you construct your splines properly (by making sure your patched areas are roughly the same size), you can use the same patch settings for your whole object. This can save you loads of time and frustration down the line. Keep these simple tricks in your back pocket and they will make your spline mod- eling job much easier. Now that we’ve covered the basics, we’re ready to start modeling. Here’s an outline of what we’ll be doing: 1. First we’ll build the spline cage. I’m going to show you how to construct a cage with great flow using the tricks outlined above. Once built, this cage can be saved and used over and over again to quickly knock out other head models. 2. Next, we’ll patch the splines, add a few details, and learn how to reduce the number of polygons to obtain an opti - mal poly count. 3. Lastly, we’ll construct the remaining details using tools you’re already famil - iar with. Fire up Modeler and let’s get started! ···· Spline Modeling Exercise 2: Modeling a Human Head 297 . applications where using spline patches can be pretty nifty. The hardest part about spline modeling in LightWave is juggling the settings in your mind so your patches end up seaming properly. (It’s a. taken your first step into a larger world.” At the time of publication, only an estimated 4% of LightWave users said that they understood spline patch modeling. You can take pride in knowing that