Non-uniform Quadratic B-spline Subdivision Non-uniform Biquadratic B-spline Subdivision Refinement rules Repeated averaging: Non-uniform linear subdivision: E=+,=9#B+sB出 di+diti ej+ejtl F=i(ditiPij+dPitij)+e(diPiti+dPij) (d+d+i)(e+ei+1) Dual averaging:Q2i.2j=(Pij +E1+E2+F) 。生 Z Huang.G Wang Non-Uniform Recursive Doo-Sabin Surfaces (NURDSes) Non-uniform Quadratic B-spline Subdivision Non-uniform Biquadratic B-spline Subdivision Refinement rules Repeated averaging: Non-uniform linear subdivision: E1 = di+1Pi,j + diPi+1,j di + di+1 , E2 = ej+1Pi,j + ejPi,j+1 ej + ej+1 F = ej+1(di+1Pi,j + diPi+1,j) + ej(di+1Pi,j+1 + diPi+1,j+1) (di + di+1)(ej + ej+1) Dual averaging: Q2i,2j = 1 4 (Pi,j + E1 + E2 + F) Z Huang, G Wang Non-Uniform Recursive Doo-Sabin Surfaces (NURDSes)