Progressive Iso-Surface Extraction from Hierarchical 3D Meshes

A multiresolution data decomposition offers a fundamental framework supporting compression, progressive transmission, and level-of-detail (LOD) control for large two or three dimensional data sets discretized on complex meshes. In this paper we extend a previously presented algorithm for 3D mesh reduction for volume data based on multilevel finite element approximations in two ways. First, we present efficient data structures which allow to incrementally construct approximations of the volume data at lower or higher resolutions at interactive rates. An abstract description of the mesh hierarchy in terms of a coarse base mesh and a set of integer records offers a high compression potential which is essential for an efficient storage and a progressive network transmission. Based on this mesh hierarchy we then develop a new progressive iso-surface extraction algorithm. For a given iso-value, the corresponding iso-surface can be computed at different levels of resolution. Changing to a higher or coarser resolution will update the surface only in those regions where the volume data is being refined or coarsened. Our approach allows to interactively visualize very large scalar fields like medical data sets, whereas the conventional algorithms would have required at least an order of magnitude more resources.