Basis Functions:

The basic functions of a Bézier surface are the coefficients of control points. From the definition, it is apparent that these two-dimensional basis functions are the product of two one-dimensional Bézier basis functions and as a result the basic functions for a Bézier surface are parametric surfaces of two variables u and v described on the unit square. Figure illustrated the basic functions for control B_2,0 (u) in the u direction and B_2,0 (v) in the v direction. In Figure (a), both B_2,0 (u) and B_2,0 (v) are illustrated along with their product. Illustrated the basis function for p_1,1, that is the product of B_2,1 (u) in the u direction and B_2,1 (v) in the v direction.