Why Use Controls?

With the character mesh visible, trying to select the correct joint can prove tricky and often frustrating. It would make things much less challenging if we could forget about the joints on the base skeleton, controlling it through other means. Adding intuitive controls to your rig will make the whole animation process easier and quicker.

Maya has a system on hand to help you with these controls. Every object has a built-in selection handle; this is displayed in the form of a small cross that you can position anywhere in the scene. You can activate these handles by going to Display > Component Display > Selection Handles.

The selection handle crosses work well to a point, but imagine that you have one cross for each joint. Looking at the example in Figure 12.1, left, can you tell which area of the skeleton is selected by which handle? Some of them are quite obvious from this angle, but imagine how difficult it would be if you were looking from the side.

Figure 12.1. Our Kila skeleton with two different control methods

This is where icons work well to represent controls. Custom-made using Maya's curve creation tools, an icon can be tailored to suit the area it will movelike the hand outline in Figure 12.1, rightso that you and other animators can easily navigate the scene.

Icons don't just help with navigation; they also help with positioning. All joints have translation values on them that cannot be frozen, and resetting them to zero will position each joint at the world root. Having icons drive the joints with an initial value of zero is useful if you need to reset the character or copy animation from one icon to another.

Another valuable asset is that you can add dynamic attributes to these control icons. A dynamic attribute added to the icon can then control a series of other attributes on a completely different object; this is done using the Set Driven Keys command under the Animate menu (which we will discuss later in the chapter). For example, you could have a single attribute on the hand icon that will pose the entire hand, making it into a fist; a value of 0 on this attribute would be the hand in its default pose, and 10 would be the fist. As you can imagine, animating the hand will go much more quickly using a dynamic attribute than it would if you had to rotate each finger joint individually and then set a key.

All that said, Maya's selection handles still have a great deal of use in our rig and, when used on a small scale, can prove invaluable.

Icon Creation

You can use anything, from locators to default curves, as iconsas long as you make it easy to identify which area of the skeleton is represented. Having the same icon/locator for each control would be just as confusing as using the default selection handle, as shown earlier in Figure 12.1, left.

Maya has some default shapes that you can choose for icons:

• A plain circle shape can be created quickly by going to Create > NURBS Primitives > Circle.

• If you only want half of the circle, you can use Create > Arc Tools.

• You can always use a locator from Create > Locator.

The default icon shapes are good solutions for quick iconic representation, but you may need more specific shapes, too, such as feet or hands. To create these, you'll use the curve tools found in the Create menu.

• The Control Vertices (CV) Curve tool creates curves based on the placements of control vertices (CVs). Each CV contributes to the overall shape of the curve.

  As demonstrated in Figure 12.2, the curve you build will not show up until you have placed the first four CVs. You will also notice that the CVs don't lie on the actual curve, so this method of creation is less helpful if you are making precise shapes.

  Figure 12.2. Creating a curve with the CV Curve tool

  

  
  

• The Edit Point (EP) Curve tool is geared more toward accurate curve creation, because each point you place lies directly on the curve.

  As you can see in Figure 12.3, unlike the CV Curve tool, the actual spline is visible once you have placed the second edit point.

  Figure 12.3. Creating a curve with the EP Curve tool

  

  
  

• The Pencil Curve tool allows you to draw your curve freehandideal when you need to trace an image or create a more complex shape.

Curve Tool Options

Each curve tool has similar options for controlling the overall shape:

• Curve Degree is perhaps the most common option used; it controls the smoothness of the curve, as illustrated in Figure 12.4.

  Figure 12.4. Available curve degrees

  

  
  

  The setting 1 Linear will give you an angular shape, with the curve following a linear path between each control point. The effects of settings 2, 3 Cubic, 5, and 7 get gradually smoother, with 7 producing the smoothest version of a curve.

• Knot Spacing adjusts the position of each edit point. Uniform will give you a predictable distribution, whereas Chord Length will improve the overall curvature.

Once the curve is created you can adjust the smoothness of a curve's display by selecting the curve and pressing 1 for a rough version of your curve, 2 for medium smoothness, and 3 for the smoothest display (Figure 12.5).

Figure 12.5. You can adjust the curve's display smoothness by pressing 1, 2, or 3.

NOTE

To help build our rigs during this chapter, we will use the ready-made icons found on the CD in Project Files/12/Icons. That folder also has a few extra icons for your convenience.