3ds Max 2012 Bible - Kelly L. Murdock [179]
The Polygon Properties rollout also includes options for setting vertex Color, Illumination, and Alpha values.
Subdivision Surface
Editable Poly objects include an extra rollout called Subdivision Surface that automatically smoothes the object when enabled. The Subdivision Surface rollout, shown in Figure 13.31, applies a smoothing algorithm known as NURMS, which stands for Non-Uniform Rational MeshSmooth. It produces similar results to the MSmooth button but offers control over how aggressively the smoothing is applied; the settings can be different for the viewports and the renderer.
FIGURE 13.31
The Subdivision Surface rollout includes controls for NURMS subdivision.
To enable NURMS subdivision, you need to enable the Use NURMS Subdivision option. The Smooth Result option places all polygons into the same smoothing group and applies the MeshSmooth to the entire object. Applying NURMS with a high Iterations value results in a very dense mesh, but the Isoline Display option displays a simplified number of edges, making the object easier to work with. The process of smoothing adds many edges to the object, and the Isoline Display option displays only the isolines. The Show Cage option makes the surrounding cage visible or invisible. The two color swatches to the right of the Show Cage option let you set the color of the cage and the selection.
The Iterations value determines how aggressive the smoothing is. The higher the Iterations value, the more time it takes to compute and the more complex the resulting object. The Smoothness value determines how sharp a corner must be before adding extra faces to smooth it. A value of 0 does not smooth any corners, and a maximum value of 1.0 smoothes all polygons.
Caution
Each smoothing iteration quadruples the number of faces. If you raise the number of Iterations too high, the system can become unstable quickly. •
The two check boxes in the Render section can be used to set the values differently for the Display and Render sections. If disabled, then both the viewports and the renderer use the same settings. The smoothing algorithm can be set to ignore smoothing across Smoothing Groups and Materials.
If the Show Cage option is enabled (at the bottom of the Edit Geometry rollout), an orange cage surrounds the NURMS object and shows the position of the polygon faces that exist if NURMS is disabled. This cage makes selecting the polygon faces easier.
Tutorial: Modeling a tooth
If you've ever had a root canal, then you know how much pain dental work can cause. Luckily, modeling a tooth isn't painful at all, as you'll see in this example.
To model a tooth using NURMS, follow these steps:
1. Select Create⇒Standard Primitives⇒Box, and drag in the Top viewport to create a Box object. Set its dimensions to 140 × 180 × 110 with Segments of 1 × 1 × 1. Then right-click, and select Convert To⇒Editable Poly from the pop-up quadmenu.
2. Click the Polygon icon in the Selection rollout to enable Polygon subobject mode. Then select the Top viewport, and press B to change it to the Bottom viewport. Then click the box's bottom polygon in the Bottom viewport.
3. Click the Select and Scale button (R), and scale the bottom polygon 10 percent.
4. Drag over the entire object to select all polygons, and click the Tessellate button in the Edit Geometry rollout once to divide the polygon into more polygons. Then select Edit⇒Region⇒Window (or click the Window/Crossing button in the main toolbar) to enable the Window selection method, and drag over the bottom of the Box object in the Left viewport to select just the bottom polygons. Click the Tessellate button again.