Graphics Reference
In-Depth Information
With this general shape formed, we can start creating a smooth shape and adding a few details. Modo fea-
tures two types of subdivision surfaces: native (which we will call
SubDs
from here out) and the latest imple-
mentation of Catmull-Clark subdivision surfaces, which are technology from Pixar (referred to as
PSubs
).
PSubs feature a more advanced method of creating smooth surfaces and offer a few additional controls over
the model. The trade-off is in the speed department. PSubs tend to render slightly more slowly than regular
SubDs. In general, this speed difference will be quite small and, for the purposes of this topic, the difference
is relatively negligible, so in most instances, we will use PSubs. The Tab key is the hot key to toggle SubDs
on and off, and the Shift+Tab combination toggles PSubs.
With that quick explanation, press Shift+Tab to turn on PSubs. You will notice that the top and bottom of
the bottle are now rounding off a bit harshly. The top is easy to deal with: because the top of a bottle has a
hole, simply select the polygon on top and cut it out (Ctrl+X or Command+X).
Deleting Polygons
For deleting polygons, use the typical “cut” operation. Pressing the Delete key gets rid of the polygon but
keeps the vertices associated with the polygon. This command (known as the Kill Polygon command)
is sometimes desirable when the vertices are needed, but the polygon is not. However, this method of
removing polygons typically results in a large number of empty vertices and should be avoided.
The bottom of the bottle needs some added detail, so you will create that now. To start, you need to add
more geometry to get the proper shape. To add the necessary divisions in the mesh, you will use two tools
that are very common in 3D modeling: Bevel and Loop Slice.
Start by selecting the bottom polygon on the bottle. The Bevel tool is located in the Polygon section on
the left side of the modeling tabs (the tabs running vertically in this window) or by pressing the B key. Bevel
the polygon by dragging the red square handle inward. Set the inset to 15 mm. Then hold Shift and click in
the viewport (not on the tool handles) to start a new bevel. This time, bevel in just 2.5 mm. This will create
a good start for adding edges and will help keep the bottom polygon from becoming distorted.
N-gons
Using
n-gons
(polygons with more than four sides) in modeling must be done carefully. Creating a ring
of four-sided polygons around the n-gon will ensure that the surface renders properly. The second bevel
will keep the bottom surface of the bottle clean and smooth.
Now you will use the Loop Slice tool to add a couple of extra edges around the bottom of the bottle.
Select two polygons running around the bottom of the bottle, leaving the bottom polygon and the surround-
ing loop alone. Run the Loop Slice tool from the Mesh Edit section or with the Alt/Option+C hot key. Set
Count to 2 and click the Uniform button in the tool options. This creates two additional edges around the
bottom of the mesh. With this geometry created, selecting the right polygons and simply moving them can
detail the bottom of the mesh very quickly. Do the following to start the bottom:
1. Select the bottom polygon and press Shift+up-arrow.
2. Select one polygon around the perimeter of the current selection.
3. Skip over three polygons and Shift+select another in the same loop.
4. Hold the up-arrow key until the rest of the pattern is selected around the loop.
