NURDSes Non-uniform Recursive Doo-Sabin Surfaces A closer look at a aj is the sum of some products of the n knot intervals,which correspond to the n vertices respectively. ai=oii+ain 1=0.l≠ ▣++心 where o=如et+元l 1=iim=-dn 月0 Z Huang.G Wang Non-Uniform Recursive Doo-Sabin Surfaces (NURDSes) NURDSes Non-uniform Recursive Doo-Sabin Surfaces A closer look at αj αj is the sum of some products of the n knot intervals, which correspond to the n vertices respectively. αj = αj,j + Xn−1 l=0,l6=j αj,l = 1 2 ( nY−1 k=0 pj+k + nY−1 k=0 qj−k) + Xn−1 m=1 ( Ym k=1 qj+k nY−1 k=m pj+k). where αj,j = 1 2 ( nY−1 k=0 pj+k + nY−1 k=0 qj−k) αj,l = Ym k=1 qj+k nY−1 k=m pj+k, m = (l − j) mod n Z Huang, G Wang Non-Uniform Recursive Doo-Sabin Surfaces (NURDSes)