Connectivity Editing for Quadrilateral Meshes Chi-Han Peng∗

mesh, (b) a rendering of the design as glass construction. In (c) and (d) we show the edited mesh. The glass panels on the roof are generated from the edges in the meshes. We propose new connectivity editing operations for quadrilateral meshes with the unique ability to explicitly control the location, orientation, type, and number of the irregular vertices (valence not equal to four) in the mesh while preserving sharp edges. We provide theoretical analysis on what editing operations are possible and im-possible and introduce three fundamental operations to move and re-orient a pair of irregular vertices. We argue that our editing op-erations are fundamental, because they only change the quad mesh in the smallest possible region and involve the fewest irregular ver-tices (i.e., two). The irregular vertex movement operations are sup-plemented by operations for the splitting, merging, canceling, and aligning of irregular vertices. We explain how the proposed high-level operations are realized through graph-level editing operations such as quad collapses, edge flips, and edge splits. The utility of these mesh editing operations are demonstrated by improving the connectivity of quad meshes generated from state-of-art quadran-gulation techniques