Feature-Sensitive Subdivision and Isosurface Reconstruction

We present improved subdivision and isosurface reconstruction algorithms for polygonizing implicit surfaces and performing accurate geometric operations. Our improved reconstruction algorithm uses directed distance fields [Kobbelt et al. 2001] to detect multiple intersections along an edge, separates them into components and reconstructs an isosurface locally within each component using the dual contouring algorithm [Ju et al. 2002]. It can reconstruct thin features without creating handles and results in improved surface extraction from volumetric data. Our subdivision algorithm takes into account sharp features that arise from intersecting surfaces or Boolean operations and generates an adaptive grid such that each voxel has at most one sharp feature. The subdivision algorithm is combined with our improved reconstruction algorithm to compute accurate polygonization of Boolean combinations or offsets of complex primitives that faithfully reconstruct the sharp features. We have applied these algorithms to polygonize complex CAD models designed using thousands of Boolean operations on curved primitives.