Page 426 - Kitab3DsMax

Part III: Modeling Basics

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. n
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 poly-
gon 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 selec-
tion 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.
5. Select the Vertex subobject mode in the Selection rollout, press and hold the Ctrl key, and select
the vertices at the center of each quadrant. Then move these vertices downward in the Left view-
port a distance about equal to the height of the Box.
6. Select the Bottom viewport again, and press T to change it back to the Top viewport. Select the
single vertex in the center of the polygon with the Ignore Backfacing option enabled in the
Selection rollout, and drag it slightly downward in the Left viewport.
7. Disable the Ignore Backfacing option in the Selection rollout, and select the entire second row of
vertices in the Left viewport. With the Select and Scale tool, scale these vertices toward the center
in the polygon in the Top viewport.
8. In the Subdivision Surface rollout, enable the Use NURMS Subdivision option and set the
Iterations value to 2.
Figure 13.32 shows the completed tooth.

378

6/30/10 4:23 PM
20_617779-ch13.indd 378 6/30/10 4:23 PM
20_617779-ch13.indd 378