Enhancement of a multi-sided Bezier surface representation

A new multi-sided surfacing scheme - the Generalized Bezier (GB) patch - has been introduced recently by Varady et al. (2016). The patch is created over a polygonal domain, its parameterization is defined by means of generalized barycentric coordinates. It has a simple control structure; the control points are associated with a combination of biparametric Bernstein functions, multiplied by rational terms. GB patches are compatible with adjacent quadrilateral Bezier patches and inherit most of their properties. In this paper we present an enhanced version of the former scheme. The control structure has been slightly modified, yielding a perfect generalization of quadrilateral patches. The parameterization has also been altered, matching a concept of how quadrilateral domains transform to n-sided polygons. We propose improved blending functions and investigate how the weight deficiency of the basis functions can be distributed amongst control points. The former rational weighting functions have been modified to support not only G(1), but higher degree continuity between adjacent patches. After briefly discussing how degree reduction and elevation proceed, we present algorithms to automatically create and optimize the internal control points of GB patches. A few simple examples and suggestions for future work conclude the paper. (C) 2017 Elsevier B.V. All rights reserved.