Optimizing mesh construction for quad/triangle schemes

Abstract

Modelling high-quality free-form 3D objects is a very time-consuming task. Recently, hybrid subdivision surface schemes have been proposed, allowing quads to be used in surface areas with two-directional symmetry and triangles for the more free-form regions. Until now, this kind of scheme was rather theoretical, as it was not obvious how to create optimal objects with it for e.g. practical animation purposes. We describe a sketching system for quick 3D modelling using such hybrid subdivision, starting from user-drawn 2D curves. These curves are triangularized, and a skeleton is calculated, along with the 3D object. This skeleton can be used to deform the object later on. At the same time, we try to maximize surface quality, and limit the number of faces and vertices. In cases where only little detail is desired, the resulting objects can be used directly, while the object's structure also makes them suitable for subsequent editing and adding detail, using commercially available subdivision modellers.