Interactive editing of multiresolution meshes

Meshes are useful to represent surfaces in computer graphics and geometric modeling. Interactive editing and deformation of meshes is very important for a variety of applications, ranging from mechanical design to animation and virtual reality. For example, deforming a parametric surface can be done by moving at least one of its control points. In case of a mesh surface, we can get a more intuitive control on deformations by directly pulling a vertex. Alternatively, as proposed in this paper, editing operations can be confined to sub-meshes. These operations are geometric transformations such as, for example, scaling, rotation, tapering and twisting. When applied to a sub-mesh, they change the shape of a mesh locally without changing its overall shape, as required for many animation applications and game technologies. Is is important to note that these editing operations are carried out in the context of multiresolution meshes. Editing a multiresolution mesh involves a three basics steps. This paper presents a new approach for interactive editing of multiresolution meshes. Editing operations (e.g. scaling and rotation) are confined to mesh regions of interest, called sub-meshes. Also, intuitive deformation operations (e.g. tapering and twisting) as required for animation systems can be used as well, allowing the user to have control on the local deformations of mesh objects. For that, each sub-mesh is defined interactively by picking up the cells of its frontier. Alternatively, a sub-mesh can be delimited by the shortest path of edges that approximates the intersection between a mesh and a given cutting plane. In order to speed up editing operations, the mesh is first simplified, the target sub-mesh is edited, and finally the whole mesh is refined back to its original resolution. This is particularly important for large meshes.