[1] Zhejiang Univ City Coll, Comp & Comp Sci, Hangzhou 310015, Peoples R China
[2] Ningbo Univ, Sch Mech Engn & Mech, Ningno 315211, Peoples R China
[3] Zhejiang Univ, State Key Lab CAD & CG, Hangzhou 310058, Peoples R China
[4] Hangzhou Dianzi Univ, Coll Comp Sci & Technol, Hangzhou 310005, Peoples R China