SolidWorks 2010 Bible

Chapter 27: Working with Surfaces

Extend Surface

The Extend Surface feature functions much in the same way that the Extend function works in
sketches. Figure 27.9 shows the PropertyManager interface and an example of the feature at work.

FIGURE 27.9

The Extend Surface PropertyManager

The only item here that requires explanation is the Extension Type panel. The Same surface option

means that the extended surface will simply be extrapolated in the selected direction. A Planar

Surface is the easiest to extend because it can go on indefinitely without running into problems. A

cylindrical surface can only be extended until it runs into itself. Complex lofted or Swept Surfaces

are often difficult to extend. Extrapolating a complex surface is not easy to do and often results in

self-intersecting faces, which cause the feature to fail.

When the Same surface setting works, it creates a nice result because it does not create an edge

where the extension begins; it smoothly extends the existing face.

The Linear option is more reliable than the Same surface option because it starts tangent to the

existing surface and keeps going in that direction, working much like a Ruled surface, which is

covered later in this chapter. It does not rely on extending the existing surface. This option creates

an edge at the starting point of the new geometry.

Trim Surface

The Trim Surface feature is described briefly earlier in this chapter, but it warrants a more com-
plete description here. Surfaces can be trimmed by three different types of entities:

l Sketches

l (^) Planes
l Other surfaces