Pseudoedge: nonintersected parametric quilt modeling of multiply connected objects

Abstract

The paper presents a new modeling approach for the representation of physical objects. In this approach, the shape of an object is expressed by its areas of prominence or high curvature, for which the term ‘pseudoedges’ is used. In terms of traditional mechanical design, these represent fillet, chamfer and intersection lines, as well as more general shape features. The pseudoedges of the model combine with a skeletal shape that is used as a starting form, thereby creating a hierarchy of geometric dependencies that allows both global and local control. The resulting surface may be closed and multiply connected, and it is represented by a quilt of parametric patches, with tangent-plane continuity being ensured by simple rules. Considerable degrees of deformation are possible, with predictable control and small computational expense; no computation of intersections or parameter-space trimming of patches are involved.