Graphics Programs Reference
In-Depth Information
FIG. 2.5
Even in a mesh made of only quads, bringing too many quads together in a single point can cause
subdivision problems.
Poles cannot always be avoided, but their ef ect can often be diminished with
appropriate spacing or edge loop rerouting, as you will see throughout the
modeling in later chapters.
Avoiding Holes
Silo will allow you to create polygons with holes (sometimes i lled with another
polygon) embedded in them. Note that this is dif erent from using several
regular, solid polygons to carve out a hole in your mesh. Polygons with holes can
be useful in the modeling process when you are not working with subdivision,
such as in architectural models. However, holes embedded within polygons will
not subdivide in a desirable way, and can cause unpredictable problems down
the road in rendering packages and game engines. Most 3D software is not built
to handle embedded holes in polygons, so you will likely want to eliminate these
before subdividing or exporting. You can do this by turning each polygon with a
hole in it into multiple solid polygons that surround an opening.
Figure 2.6 shows two objects with holes. The i rst simply has a missing
polygon, and will cause problems in subdivision and when trying to use the
object in other programs. The second has a hole all the way through the
object connected on all sides by polygons, and won't cause problems.
M aintaining Appropriate Polygon Density
One of the hardest senses to gain as a novice 3D modeler is how much detail
to add to a model, and when to do so. Most professionals lean on the side of
keeping the polygon density as low and uniform as possible until adding more
geometry for specii c details becomes necessary. Throughout this topic you will
see how, when using box modeling techniques, we dei ne all the larger, simpler
shapes, such as arms and legs, before going into details like i ngers or toes.
