Source : Free On-Line Dictionary of Computing

Bezier surface
     
         A surface defined by mathematical formulae, used in
        {computer graphics}.  A surface P(u, v), where u and v vary
        orthogonally from 0 to 1 from one edge of the surface to the
        other, is defined by a set of (n+1)*(m+1) "control points"
        (X(i, j), Y(i, j), Z(i, j)) for i = 0 to n, j = 0 to m.
     
        	P(u, v) = Sum i=0..n {Sum j=0..m [
        		(X(i, j), Y(i, j), Z(i, j))
        		* B(i, n, u) * B(j, m, v)]}
     
        	B(i, n, u) = C(n, i) * u^i * (1-u)^(n-i)
     
        	C(n, i) = n!/i!/(n-i)!
     
        Bezier surfaces are an extension of the idea of {Bezier
        curves}, and share many of their properties.
     
        (1996-06-12)