Introducing Sweep Features in Modeling with Subdivision Surfaces

In recent times, subdivision surfaces have been considered a powerful representation for shape design. They have been successfully introduced in character animation software packages. In the last few years they have obtained greater attention also from CAD applications due to their potential in overcoming some of the problems intrinsic of spline-based modeling. Anyhow, their major drawbacks are related to the difficulty in constraining the shape of the limit surface and to the limited high level modeling tools to manipulate the shape. In this paper, we propose a feature-based approach to extend the modeling capabilities of subdivision surfaces and to allow users to deal with this new modeling technique closer to the way they are used to. In particular, features obtainable by means of generalized sweep operations are formalized and treated. This type of feature has been chosen because it covers a large set of shapes commonly appearing in industrial products (e.g. car door internal panel cavities, stiffeners, ...).