Graphics Reference
In-Depth Information
Fig. 14.14
The two patch groups labeled
A
have identical patch layouts despite their shape
differences. Patch group
B
is connected to
A
at seam
S01
14.3.3
Patch Layout
When working with NURBS for the fi rst time it can be helpful to approach the
problem schematically by sketching a
patch layout
(Fig.
14.14
). Instead of worrying
about specifi c shapes, you fi rst determine the total number of parts and how they are
attached to each other. This will allow you to understand the topological structure of
your object better. After you have an idea how each part is related to the others, you
can analyze their shapes.
14.3.3.1
Patterns
The complexity of a network is increased when the number of connections or the
number of nodes infl uenced by each node is increased. The addition of nodes if they
have only one connection does not increase the topological complexity of the prob-
lem (Figs.
14.15
and
14.16
).
14.3.4
Topology of Tools
For any NURBS surface, its interior is defi ned by the intersection of U and V
isoparms that are defi ned by your curves or tool settings. These intersections create
a grid network of CVs within your surface that may be used to further modify it.
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