Extraordinary patches:distance bound Limit face F(4,v)can be partitioned into bilinear subfaces defined over: Fu,儿t=F(tu,》 Similar to the regular case,for (u,)e S(u,)-F(4,=小S(u,-F(u,) 22,-B四8O By solving 16 constrained minimization problems,we have lb-b≤cM,0≤i,j≤3 Extraordinary patches: distance bound  Limit face can be partitioned into bilinear subfaces defined over :  Similar to the regular case, for  By solving 16 constrained minimization problems, we have F( , ) u v k  m ( , ) k m u v  ( , ) ( ( , )) k m k k m m u v u v  F F t = ( , ) ( , ) ( , ) ( , ) k k m m S F S F u v u v u v u v − = − 3 3 3 3 , , 0 0 i j ( ) ( ) i j i j i j B u B v = =  −   b b 0 , 3   i j , , , i j , i j i j b b−  c M