Time Critical Isosurface Refinement and Smoothing

Multi-resolution data-structures and algorithms are key in Visualization to achieve real-time interaction with large data-sets. Research has been primarily focused on the off-line construction of such representations mostly using decimation schemes. Drawbacks of this class of approaches include: (i) the inability to maintain interactivity when the displayed surface changes frequently, (ii) inability to control the global geometry of the embedding (no self-intersections) of any approximated level of detail of the output surface. In this paper we introduce a technique for on-line construction and smoothing of progressive isosurfaces (see Figure 1). Our hybrid approach combines the flexibility of a progressive multi-resolution representation with the advantages of a recursive subdivision scheme. Our main contributions are: (i) a progressive algorithm that builds a multi-resolution surface by successive refinements so that a coarse representation of the output is generated as soon as a coarse representation of the input is provided, (ii) application of the same scheme to smooth the surface by means of a 3D recursive subdivision rule, (iii) a multi-resolution representation where any adaptively selected level of detail surface is guaranteed to be free of self-intersections.