Chapter 27: Working with Surfaces
Revolved Surface
The Revolved Surface functions like its solid counterpart, right down to the rules for how it han-
dles entities that are touching the axis of revolution; nothing can cross the axis. A single sketch
entity is allowed to touch it at a single point, but multiple sketch entities cannot touch it at the
same point.
Swept Surface
Swept Surfaces work much like their solid counterpart, and the sketch rules and available entities
are the same. The main difference here is going to be that Swept Surfaces usually use an open con-
tour for the profile, while swept solids use closed contours.
Lofted Surface
The main difference between Lofted Surfaces and lofted solids is that the surfaces can use edges
and curve features as profiles, rather than simply sketches and faces.
Boundary Surface
The Boundary Surface was created as a higher quality replacement for the Loft feature, but certain
limitations mean that Loft has not been removed from the feature list. The Boundary Surface most
resembles a loft, but has elements of the Fill Surface, and at times can also function like a sweep. It
requires you to select edges or sketch elements in two different directions, directly relating to the
NURBS scheme I discussed earlier in this chapter. This feature can work with only one set of edges
selected.
If several edge or sketch segments combine to form one side of a direction, then you must use the
SelectionManager to form the edge segments into a group. SelectionManager enables you to select
portions of a single sketch or to combine elements such as sketch, edge, and curve into a single
selection for use as a profile or guide curve for Boundary or Loft features.The interface for the Boundary Surface is shown in Figure 27.4.The types of models where you end up using the Boundary Surface are highly curvy models that
are modeled mainly with surface features and require a four-sided patch.The main advantage of Boundary Surface over Loft is that Boundary Surface can apply a Curvature
boundary condition all the way around, while Loft cannot apply curvature on the guide curves. Fill
Surfaces also can apply a Curvature boundary condition all the way around.Boundary Surface can be a rather nuanced feature, but when working on the type of model that
suits it well, I default to Boundary Surfaces when possible. Boundary solid features are now also
available, and I expect these will also take a little bit of a learning curve to understand where they
are best applied.