By combining techniques for smooth surface remeshing with some clever
optimizations, we were able to develop Delaunay refinement algorithm
for meshing isosurfaces with guaranteed topology and approximate
geometry. The algorithm is split into two stages; the first akin to
traditional Delaunay refinement and in the second the Delaunay
triangulation is discarded entirely--greatly improving the running
time. More details can be found in the following papers.
T. K. Dey and J. A. Levine. Delaunay meshing of isosurfaces. Proc. Shape Modeling International (2007), 241-250.
T. K. Dey, G. Li and T. Ray. Polygonal surface remeshing with Delaunay refinement. Proc. 14th Intl. Meshing Roundtable., 2005, 343--361.
The DelIso software based on this result is available.