TY - JOUR
T1 - Visual Smoothness of Polyhedral Surfaces
AU - PELLIS, DAVIDE
AU - Kilian, Martin
AU - DELLINGER, FELIX
AU - Wallner, Johannes
AU - Pottmann, Helmut
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported by the SFB-Transregio programme Discretization in geometry and dynamics, through grant I2978 of the Austrian Science Fund. The authors are grateful to Felix Günther for useful discussions, and to the anonymous referees for extensive reviews.
PY - 2019/7/12
Y1 - 2019/7/12
N2 - Representing smooth geometric shapes by polyhedral meshes can be quite difficult in situations where the variation of edges and face normals is prominently visible. Especially problematic are saddle-shaped areas of the mesh, where typical vertices with six incident edges are ill suited to emulate the more symmetric smooth situation. The importance of a faithful discrete representation is apparent for certain special applications like free form architecture, but is also relevant for simulation and geometric computing.
In this paper we discuss what exactly is meant by a good representation of saddle points, and how this requirement is stronger than a good approximation of a surface plus its normals. We characterize good saddles in terms of the normal pyramid in a vertex.
We show several ways to design meshes whose normals enjoy small variation (implying good saddle points). For this purpose we define a discrete energy of polyhedral surfaces, which is related to a certain total absolute curvature of smooth surfaces. We discuss the minimizers of both functionals and in particular show that the discrete energy is minimal not for triangle meshes, but for principal quad meshes. We demonstrate our procedures for optimization and interactive design by means of meshes intended for architectural design.
AB - Representing smooth geometric shapes by polyhedral meshes can be quite difficult in situations where the variation of edges and face normals is prominently visible. Especially problematic are saddle-shaped areas of the mesh, where typical vertices with six incident edges are ill suited to emulate the more symmetric smooth situation. The importance of a faithful discrete representation is apparent for certain special applications like free form architecture, but is also relevant for simulation and geometric computing.
In this paper we discuss what exactly is meant by a good representation of saddle points, and how this requirement is stronger than a good approximation of a surface plus its normals. We characterize good saddles in terms of the normal pyramid in a vertex.
We show several ways to design meshes whose normals enjoy small variation (implying good saddle points). For this purpose we define a discrete energy of polyhedral surfaces, which is related to a certain total absolute curvature of smooth surfaces. We discuss the minimizers of both functionals and in particular show that the discrete energy is minimal not for triangle meshes, but for principal quad meshes. We demonstrate our procedures for optimization and interactive design by means of meshes intended for architectural design.
UR - http://hdl.handle.net/10754/653104
UR - https://dl.acm.org/doi/10.1145/3306346.3322975
UR - http://www.scopus.com/inward/record.url?scp=85073887269&partnerID=8YFLogxK
U2 - 10.1145/3306346.3322975
DO - 10.1145/3306346.3322975
M3 - Article
SN - 0730-0301
VL - 38
SP - 1
EP - 11
JO - ACM Transactions on Graphics
JF - ACM Transactions on Graphics
IS - 4
ER -