Sweepers: Swept deformation defined by gesture

Sweepers is a framework for defining space deformation operations for interactive shape modeling. The artist describes a basic deformation as a path through which a tool is moved. Our tools are simply shapes. So we can use shapes already created as customized tools to make more complex shapes or to simplify the modeling process. When a tool is moved, it causes a deformation of the working shape along the path of the tool. More complicated deformations are achieved by using several tools simultaneously in the same region. It is desirable that deformations for modeling are 'foldover-free,' so that the deformations are reversible. Our deformations can satisfy this criterion. We have an efficient formulation for a single tool following a simple path and we have a formula for blending conveniently the effects of multiple tools used simultaneously. For representing shapes, we provide a mesh refinement and decimation algorithm specially adapted to our deformations.