Takashi Kanai Yutaka Ohtake Kiwamu Kase Hierarchical error-driven approximation of implicit surfaces from polygonal meshes. 21-30 2006 conf/sgp/2006 Symposium on Geometry Processing http://doi.acm.org/10.1145/1281957.1281960 db/conf/sgp/sgp2006.html#KanaiOK06