- Character Model Basics
- Starting a Model
- Continue Refining Your Model
- Smoothing
- Crease Edges
- Combining Geometry
- Summary
- Q&A
- Workshop
This chapter is from the book
This chapter is from the book
This chapter is from the book
Continue Refining Your Model
Continue extruding and positioning faces to create the rest of the character’s body geometry. Leave the arms out for now. You may want to make use of the Append to Polygon tool instead of merging vertices. To use this tool, select it by going to Edit Mesh, Append to Polygon Tool. Once it is active, select the open edge you would like to close. Triangular manipulators will appear on the edges in the mesh that you can select to create the new polygon. Click on any of them to create the new polygon; then press Enter to finish the tool. Once you have created the rough geometry for the entire character, you can go back and use the Interactive Split tool to redefine the edge loops. Look for areas where the edges are getting crossed and disorganized. You can use the Interactive Split tool to make some splits, and then delete the old edges to make things look like they are working better. In general, try to get the geometry evenly spaced and the edge loops looking smooth in all directions. As you get more practice, it becomes easier to predict how your geometry will turn out.
Multi-Edged Intersections: Poles
You may notice that you are getting many “poles” in your geometry. A pole is any vertex that is at the intersection of more than four edges. A certain number of poles is unavoidable because of the different elements you need to fit together in a single mesh. A character that has many circular edge loops close together is especially prone to having poles. Even our character has poles in his face near the eye socket. We do want to try to reduce the number of poles as much as possible because they are another problem for smoothing at render time. And we definitely want to try to get rid of poles in any place that is going to have a lot of deformation happening; they will introduce smoothing errors. Figure 8.18 shows some poles in our model.
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FIGURE 8.18. Poles are anywhere that more than four edges meet. Maya doesn’t know how to subdivide these areas nicely.
Remember from Hour 4 we talked about how it is ideal to have three- and four-sided faces in our models? One way to reduce the number of poles you have from the outset is to try as hard as possible to make sure you only have four-sided faces, and that your edge loops are as long as possible. This will help ensure you are not creating tangled nests of polygons. Chances are your edge loops are terminating at poles; therefore, if you double-click on an edge, follow the selected edge loop to its ends to discover poles.
A place where poles are guaranteed to appear is anywhere a face is extruded from a plane. The vertices already have four edges intersecting at them, and you are essentially adding one more. If you think of the most low-poly bipedal shape possible, you will see that poles are unavoidable wherever appendages are extruded (see Figure 8.19).
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FIGURE 8.19. This very simple representation of a bipedal character illustrates how some poles are unavoidable. Even when smoothed (right), the poles remain. Keeping poles to a minimum is the mark of a good character modeler.
Adding the Arms
Seeing as having a few poles is unavoidable, we’re going to extrude the polygons that make up the arms from the open edges on his side. If you want to start from the same point as I have, open character_Mid.ma in this Hour’s source files. Go into the Edges component mode and double-click on the open edge loop on his sides. Use the Edit Mesh, Extrude tool to extrude his arms all the way to the wrists. This time, we’re going to add detail using the Insert Edge Loop tool to give ourselves detail where we need it. Select Edit Mesh, Insert Edge Loop and click a few times along the arm, putting at least three loops near the elbow. When that is done, you can go into the vertex component mode and make the adjustments you need to get the vertices to line up with the design.
This character was designed with “mitten hands” so that it would not be too challenging to try to get the hands in place. Keep extruding, appending, and adjusting vertices to get the hands in place, as shown in Figure 8.20.
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FIGURE 8.20. The completed hand has a thumb and a tapered “mitten” for fingers.
Note
Legs Cover the Real Center
Notice how our character’s arms are basically not visible in the side panel’s image plane. Because they don’t block any geometry they are visible in the side drawing. Legs, however, do block crucial information—where the center edge loop goes from front to back through the groin area. On most side-view designs, the center edge loop is drawn even though it should be blocked by the leg (see Figure 8.21).
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FIGURE 8.21. A common practice is to show the center edge loop even though it is blocked by the leg.
Low-Poly Workflow
As we move ahead, we should start thinking about the workflow that this character is going to go through. One of the more popular workflows is to export your geometry in a low-polygon state to a piece of 3D sculpting software to add details and then apply those details to the low poly at render time with something called a “displacement map.” This workflow saves a lot of scene overhead because Maya does not handle millions of polygons in panel very well, nor could you possibly animate a character that had that much detail.
Working “low poly” means that you aren’t necessarily trying to model detailed parts of the character into the geometry. This is particularly true for details such as buttons on a shirt, belts, arm bands, and so on. These small details would be better suited to be separate objects that you either constrain or rig to move along with the character geometry rather than being built into the single character mesh. A good rule of thumb is that anything that is “skin tight” can be a part of the character model, and anything that is not should be a separate object. Just imagine how hard it would be to have good edge loops if you had to add really tiny details to a low-poly object.
The last advantage to a low-poly workflow is the fact that you are simply dealing with fewer polygons. When we get to rigging and skinning this character, you will see that having fewer polygons to deal with is extremely advantageous. Particularly when we are creating shapes for the eyelids and mouth for animation, our low-poly character will be very simple to set up to take on some very dynamic shapes.
Problem Areas
Characters have some areas that traditionally can give us a lot of trouble. Therefore, you need to know what these areas are and some good methods for keeping out of trouble.
Inside the Mouth
Inside the mouth can be tricky to model because it is hidden by other geometry, and you have to decide what kind of mouth interior you want before you go about creating it. It can be a good idea to create a hollow mouth interior and have separate geometry for the teeth and tongue to avoid the problems mentioned before concerning detail and edge loop efficiency. The mouth interior does not have to be very big; a common beginner mistake is to make the mouth large, but we won’t fall into that trap. Figure 8.22 shows a good-sized mouth interior.
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FIGURE 8.22. Our character with a hollow mouth added. We can add the teeth and tongue later if we wish.
Armpits and Shoulders
We created the arms by extruding an open edge loop on the side of the body, which created four poles. For our purposes, this shouldn’t work out to be too disruptive in either the animation or the smoothing processes, but you should know anyway that armpits and shoulders are challenging. The reason they present such a challenge is that they have a very wide range of motion, and they take on very different shapes depending on if the arm is up, down, forward, or back. We create our character in T-pose (with arms perfectly out to the sides) because with most cartoon characters this pose represents the middle of the range of motion. On some feature film rigs, the arms are modeled to be more relaxed, slightly lowered and a little bit bent forward at the elbow. This is done because, in reality, our range of motion for most common tasks is very narrow. Because our character has very little armpit or shoulder definition, just a tiny bit of bulge on top and a little bit of indentation on the bottom of the arm will suffice. In Figure 8.23, the poles that were created on his arm area are shown, but there shouldn’t be problems with smoothing or deformation here.
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FIGURE 8.23. The arms of our character are not so bulky or defined that we’ll run into deformation or smoothing problems with the poles that were created, but you should keep it in mind for future characters.
Hands
Our character’s hands do not have much detail, but with realistic characters with multiple fingers, the hands are a challenge. The issue is getting enough edges into the fingers to nicely define the shape, without having to terminate too many of those edges at the wrist and create nasty poles. Most hand models use the same extrusion we did for this character’s arms on each of the fingers, making it so the poles that would be created for the finger detail end up between the fingers and not all bunched up in the wrist.
Eyelids
Our character has very simple eyes with nice bulky eyelids. For characters with more realistic, thin eyelids, they are normally modeled closed so that by using rigging tools and deformers, they can be opened nicely. It is done this way because it is easier to rig an eye to open than it is to untangled the scrunched up geometry of a closed eyelid and make it close nicely. Ours is modeled open solely because of the fact our character is cartoony, unrealistic, and, most importantly, low poly.
Elbows and Knees
These two areas are just like the armpits and shoulders in that they will either flatten out or get bunched up when deforming. Also, elbows and knees actually take on very different shapes (due to the bones changing position and pushing the skin out) when they are bent than when they are relaxed. We can use something called BlendShapes (described in Hour 15, “Making Diverse Shapes with BlendShapes”) to change the shape of the elbows and knees depending on whether they are bent or not. Therefore, to avoid problems, model the knees and elbows in their clearly relaxed poses, not something halfway, which might be intuitive to avoid problems.
Density
When you’re modeling characters, it’s common to be focused on the section you are working on, and only worry about the overall model density later on. However, it is a good practice to have an idea of how dense the geometry is going to be on your character before you begin. Certain areas need more density, or they will not behave correctly when they deform. This is why we added extra edge loops near the elbow of our character. To make very sure we get the exact shape we want out of him, go back in and add some more detail on his elbow, as seen in Figure 8.24. When it comes time to rig these elbows, I know we’ll have enough detail to get the results we want.
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FIGURE 8.24. The elbows can be problem areas if you don’t have enough geometric detail, or density, in the areas where they deform.
Besides areas that are going to deform, you also want more density in areas that are going to get the most screen time. For this reason, the face and head are typically the densest regions on your character model. Taking a step back and looking at our character model proves this is true, even with cartoony characters, as you can see in Figure 8.25.
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FIGURE 8.25. The detail is higher in the face than anywhere else because it will deform, but mostly because an audience spends the majority of their time watching the face!
The one other consideration for density is for any effect that relies on polygonal detail. Some particle systems generate particles per face, and if your mesh is too lopsided in detail, it can create some odd effects. Some third-party fur plugins generate hairs based on polygons as well; again, having far too much detail in one section and far too little in another can mean unpredictable results.