Page 275 - Mastering SolidWorks

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understanding Fillet tyPes 247

Figure 7.33
a face fillet cover-
ing geometry

On the Website

the model used for this image can be found in the download materials from the wiley website for
this chapter; look for the filename Chapter 7 Plastic Cover Fillets.sldprt.

Using Face Fillets with the Help Point
The Help Point in the Face Fillet PropertyManager is a fairly obscure option. However, it is
useful in cases where the selection of two faces does not uniquely identify an edge to fillet. For
example, Figure 7.34 shows a situation where the selection of two faces could result in either one
edge or the other being filleted (normally, I would hope that both edges would be filleted). The
fillet will default to one edge or the other, but you can force it to a definite edge using the
Help Point.
In some cases, the Help Point is ignored altogether. For example, if you have a simple box,
and select both ends of the box as Selection Set 1, and the top of the box as Selection Set 2, then
the fillet could go to either end. Consequently, assigning a Help Point will not do anything,
because multiple faces have been selected. The determining factor is which of the multiple faces
is selected first. If this were a more commonly used feature, the interface for it might be made a
little less cryptic; but because this feature is rarely, if ever, used, it just becomes a quirky piece
of trivia.
Applying a Single Hold-Line Fillet

A single hold-line fillet is a form of variable-radius fillet. Rather than the radius being driven by
specific numerical values, it is driven by a hold line, or edge, on the model. The hold line can be
an existing edge, forcing the fillet right up to the edge of the part, or it can be created by a split
line, which enables you to drive the fillet however you like. Figure 7.35 shows these two options,
before and after the fillets. Notice that these fillets are still arc-based fillets; if you were to take a
cross section perpendicular to the edge between filleted faces, it would be an arc cross section
with a distinct radius. However, in the other direction, hold-line fillets do not necessarily have a
constant radius, although they may if the hold line is parallel to the edge between faces.