1Pi Xuexian, Yang Xudong, Li Sikun. High-perform ance navigation and rendering of very-largescale landscape and seascape [ C]//ComputerA ided Design and Computer Graphics, 2005 Ninth International Conference. [ S. 1. ] : [ s. n. ] ,2005.
2Bradshaw G O,Sullivan C. Adaptive medial - axis approxi- mation for sphere-tree construction [ J ]. ACM Transactions onGraphics, 2004,16 (2) : 1 - 26.
3Raffin R, GesquiereG, Remy E. VirSculpt : a virtual sculp- ting environment [ C ]//GraphiCon'04 Proceedings. [ S. 1. ] : [s.n. ], 2004:184-187.
4Suri S, Hubbard P M, Hughes J F. An alyzing bounding box for objectintersection[J]. ACM Transaction on Graph- ics,2006, 18(3) :257 -277.
7Mark de Berg, Marc van Kreveld,Mark Overmars, et al. Com- putational geometry: algorithms and applicationsEMJ. Secau- cus NJ : Springer2Verlag New York Inc, 1997.
