Presented at the First International Symposium on 3D Data Processing, Visualization, and Transmission held in Padua, Italy, June 19-21, 2002, this 11-page paper by James Davis, Stephen R. Marschner, Matt Garr, and Marc Levoy presents an algorithm that can fill holes in 3D models using volumetric diffusion. Using a 3D model of a section of hair from a photograph of the Michelangelo's David, the authors illustrate how certain holes are too "geometrically and topologically complex to fill using triangulation algorithms." As a result, they have come up with a solution that entails a "signed distance function," and a diffusion process that extends this function through the volume until its zero set bridges with existing holes. For science enthusiasts interested in filling holes in 3D models, the authors assert that the "algorithm is simple to implement, is guaranteed to produce manifold non-interpenetrating surfaces, and is efficient to run on large data sets."