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616 | Chapter 21 Surfacing Wireframe Models
Review the wireframe in detail, to determine where you will have design
challenges.
Consider the following:
■ The complexity of the surfaces you need to create. For example, what
curvature is required of surfaces? Is it sufficient to have surfaces with no
curvature (such as ruled surfaces), or do you need surfaces with multiple
curvatures?
■ How you can simplify shapes. Surfaces created from polylines or splines
with a large number of points are complex and greatly increase computa-
tion time.
■ Which surfaces are continuous. Continuous surfaces are smoother and
take less time to compute. You can set preferences so that lines with breaks
or changes in curvature aren’t converted to splines.
■ Are default preference settings appropriate for the model. Allow as much
tolerance as is practical to avoid converting polylines to splines. Splines
take longer to compute than polylines—a factor that becomes more
important with complex models.
Identifying Logical Surface Areas
Once you determine the intent of the pump design, you get an idea of the
requirements for creating its shape and for constructing it. Identify the loca-
tion and extent of each logical surface area—an area that can be described by
a single surface.
A surface must be smooth and free of sharp breaks. Often, an individual sur-
face area is clearly-defined because it is surrounded by sharp break lines on
all sides. The pump top is a surface because it is surrounded by sharp edges
on three sides. The fourth edge is the end of the part.