On local deformations of planar quad-meshes

  • Authors:
  • Tim Hoffmann

  • Affiliations:
  • Zentrum Mathematik, Technische Universität München

  • Venue:
  • ICMS'10 Proceedings of the Third international congress conference on Mathematical software
  • Year:
  • 2010

Quantified Score

Hi-index 0.00

Visualization

Abstract

Planar quad-meshes (meshes with planar quadrilateral faces - PQ-meshes for short) are an important class of meshes (see e.g. Bobenko and Suris [2008]). Although they are often desirable in computer graphics - since planar quads can be rendered with out triangulating them - and architectual geometry (see Pottmann et al. [2007]) - because building with planar tiles ismore cost effective - modelling freeform surfaces with planar quadrilaterals is problematic (in fact in practical applications one deforms or subdivides PQ-meshes without obeying the planarity constraint and ensures it afterwards in a global optimization step). In this paper we present a method that allows local deformations of PQ-meshes (with square grid combinatorics) that makes it possible to modify a PQ-mesh while keeping all quadrilaterals planar through the whole process (without a minimization step). In principle the method allows for PQ-mesh subdivision as well. The deformation scheme outlined in the following is a new approach and it is currently implemented in a prototype stage by Christian Hick. The general idea is that while moving a single vertex will generically destroy the planarity of the adiacent faces, moving the plane of a face and allowing its four points to adjust as necessary, has exactly enough freedom to generically allow for planarity of the central face as well as its neighbours.