Maya Rendering Guides

Editing the Body

Fleshing out the body involves splitting polygons and moving vertices into position. Splitting polys effectively involves judicious use of Maya's splitting and cutting tools and a working knowledge of how those split polys will be smoothed. Our goal is to create a model with as low a polygon count model as possible while still creating the detail necessary so that when smoothed at render time, the model will look good. Maya's smooth function is powerful, but it can be difficult to control.

Figure 3.19 illustrates how Maya's polySmoothProxy node works and provides a guide for how we will be modeling. Figure 3.19a shows that Maya smooths two polygons into eight and demonstrates that the act of subdividing polygons by a factor of 1 actually increases the polygon count by a power of 4. This is why judicious and careful use of the splitting, cutting, and subdividing toolsets is an important skill to master. Splitting the proxy object in the middle of the polygons tightens the bend somewhat in Figure 3.19b, but moving that edge down to the corner in Figure 3.19c tightens the bend in the smoothed object. Figure 3.19d through f illustrate how to tighten an edge to bring back the hard corners by splitting the polys near the edge. The closer the polygon edges on a proxy model, the tighter the corner or other detail on the smoothed model.

Maya's polySmoothFace node (choose Mesh ■ Smooth) smooths in much the same way as Smooth Visually, but the point order of a polySmoothFace object will be different from that of a polySmoothProxy object. This is crucial if you are using deformers such as BlendShapes that rely on point order to work properly.

Figure 3.19 This Subdiv Proxy example illustrates how to control Maya's smooth function.

In editing Machismo's body, it is useful to try to do as much with the points you have to match the desired shape, and only when you have done all you can should you cut or split polygons. It is far too common for beginning modelers to subdivide the model too much at the outset and then have to contend with large numbers of points. We will subdivide/smooth the model once and move points into position. This box modeling technique works much like sculpting clay. We will work from large general shapes and model down to specific details. This is the essence of box modeling. Let's edit this model as follows.

1. RMB click the proxy object and choose Vertex. Select and pull the vertices to match the shape shown in Figure 3.20. While you are translating the vertices on the proxy object, you want to watch the smoothed object on the right. If the smoothed object is too rough at this stage, you can press the PageUp button to increase its density.
2. With the model selected in object mode, choose Mesh ■ Smooth Under the Exponential Controls section, uncheck all the properties under the Preserve label. Map Borders can be set to Smooth Internal.
3. Click Smooth. You should have something like Figure 3.21.

Figure 3.20 Moving the vertices at the start of editing. Notice how the vertices on the proxy object extend far outside the lines of the template while the smoothed object stays largely within the outline.

Figure 3.21 After smoothing, you now have more points to contend with, but it should be quite manageable.

We will now edit the smoothed proxy object using Maya's Move Normal function along with "pick-walking" polygonal vertices using the keyboard's arrow keys. We'll edit this model as follows.

1. RMB click the proxy object and choose Vertex.
2. Hold down the W key and click a vertex to open the Move tool's marking menu. Select Normal. This feature is usually used with NURBS CVs. But when pulling individual vertices, it can be used to quickly move points either along the surface or outward along the vertex normal. This makes it useful for our purposes because many times when editing, it makes more sense to pull points once along the normal as opposed to pulling them in X, then Y, then Z.
3. Select the vertex shown in Figure 3.22. Note that the manipulator is oriented on the U, V, and N axes. This makes it useful for editing individual points as we can move the points more along the surface of the model.
4. With the top view active (MMB click in that window), press the Down arrow key. Note that the U and V axes flip. This shows why the Move tool set to Normal is effective only with single points: if you try to use this tool to move multiple points in U or V directions, they will move in unpredictable ways.
5. Pull the front three vertices outward along the normal until the smoothed object expands to match the template. Notice that when you pull the center line vertex, it does not pull parallel with the center line plane; it overlaps the smoothed object. This is generally undesirable. You may need to pull it back along the U axis until it lines back up.

Continue around the figure either using the arrow keys or simply clicking to select each vertex. Move vertices either along the normal or local axes (by using LM with the W key held down to switch between them) to model the figure to match what you see in Figure 3.23. Notice that we moved the points at the bottom of the proxy figure up. We will extrude the waist and legs later.

Figure 3.22 Choose the vertex in the front corner of the model. Then use the arrow keys to pick-walk around the model.

Figure 3.23 The model at this point

Figure 3.23 The model at this point