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Basic Concepts of Surfacing Wireframe Models | 623
The easiest method is to use a single rail and a single section to surface the
entire area, then trim the base surface to the intersecting part of the pump.
This choice might not always be correct. As you gain experience, you can pre-
dict which approach yields the most accurate results. In the previous exam-
ple, verify that the surface created without the top line matches the top line
within a reasonable tolerance.
Always check the fit between a newly created surface and existing wires to be
sure that you are not deviating too far from the wireframe data. If the new
surface is not within tolerance to the existing top line, the surface does not
accurately reflect the wireframe. You can re-create it using all four wire edges.
Verifying Surfacing Results
As you gain experience, you will see the importance of learned skill and judg-
ment. Your challenge is to produce smooth surfaces that fit the wireframe
closely; the surfaces should be as simple as possible.
You can judge the smoothness of surfaces several ways:
■ Analyze a surface and view its color-shaded display to detect small devia-
tions in surface smoothness.
■ Create and review flow lines in different rotated views.
■ Cut sections through a complete set of surfaces, and then examine the
ends to see how closely they match at the edges.
■ On the surface create augmented flow lines with long vectors and examine
the smoothness of the vector ends. The ends of the vectors exaggerate the
smoothness of the surface; areas where it is not smooth become apparent.
rail
section
surface trimmed surface