TABLE OF CONTENTS Using surface profile curves discussed in Section 10.3, we can create various surface models. According to the usage of surface profiles in modeling, we can categorize surface models into: (1) single-profile surface models; and (2) multiple-profile surface models. When creating surface models by single profile, there are only two modeling options: revolved and extruded. Revolving a single profile curve will result in surface models with various radii of rotation, whereas extruding a single profile curve will result in the expansion of the curve to having a surface model.
When surface models are created by multiple-profile curves, there are, again, different scenarios according to the number of groups of curves used: (1) single group profiles; (2) two groups of profiles; and (3) three groups of profiles. In the first scenario, all the profile curves are in the same general orientation, whereas in the second scenario, a second group of profile curves will interweave with the first group of profile curves in different angles. In the third scenario, there is a spine profile curve(s) in addition to the two groups of profiles.
In surface modeling practices, we often extract these models by categorizing them into the three groups of surface profile curves just defined. We may call one group the cross-section profiles and the second group the transitional profile, as they govern the transitions between cross section profile curves. According to the modeling intent, either cross-section profiles or transitional-profile curves may be interchangeable.
