Interactive Patient-Specific Vascular Modeling with Sweep Surfaces
A technique is presented for generating implicit sweep objects that support direct specification and manipulation of the surface with no topological limitations on the 2D sweep template. The novelty of this method is that the underlying scalar field has global properties which are desirable for interactive implicit solid modeling, allowing multiple sweep objects to be composed. A simple method for converting distance fields to bounded fields is described, allowing implicit sweep templates to be generated from any set of closed 2D contours (including "holes"). To avoid blending issues arising from gradient discontinuities, a general distance field approximation technique is presented which preserves sharp creases on the contour but is otherwise <i>C</i><sup>2</sup> smooth. Flat endcaps are introduced into the 3D sweep formulation, which is implemented in the context of an interactive hierarchical implicit volume modeling tool.