Modeling quadrilateral meshes by composition

Abstract

In this work we address the problem of modeling quadrilateral meshes by composition, i.e., by stitching together parts. We get to build pure quadrilateral meshes in the spirit of Constructive Solid Geometry (CSG), but working only with quadrilateral meshes. Our proposal to compose quadrilateral meshes preserves the majority of the original layout of the parts, i.e, it keeps untouched all the quads in the patches which are not involved in the blending, and runs at interactive rates. We use a number of well-established techniques to achieve a stable implementation, but in short, we first perform robust boolean operations on the corresponding triangle meshes, then we use this result to identify and build new surface patches for small regions neighboring the intersection curves. These blending patches are carefully quadrangulated respecting boundary constraints and stitched back to the untouched parts of the original models. The resulting mesh preserves the designed edge flow that, by construction, is captured and incorporated to the new quads as much as possible. At the end, we present some results showing the potential of our prototype for real applications, in particular, with models designed for animation.