<\body> Bézier surfaces are special types of rational surfaces, which use Bernstein bases to represent the polynomial functions. \ Several types of Bézier surfaces exist. A or Bézier parametric surface is the image of a map : [a,b]**\[c,d]\ \> of the form <\equation*> (s,t)\[a,b]**\[c,d]\>>\ B>(s;a,b) B>(t; c,d)\ where \\> are the control points, and (s; u,v)= (s-u)(v-s)>, d)> are the Bernstein basis elements of degree for the interval . A rational tensor-product Bézier surface is constructed as follows: <\equation*> (s,t)\[a,b]**\[c,d]\>>w \ B>(s;a,b) B>(t; c,d) |>>w B>(s;a,b) B>(t; c,d)> where \\> are the of the control points (usually \0>). The bidegree of the parametrisation is ,d)>. A or Bézier parametric surface is the image of a map : \ T\ \> of the form <\equation*> s\T\> (s;A,B,C)> where > is the triangle defined by the points \>, \ \\> are the control points, and (s;A,B,C) = \ s s s>, ,s,s)> are the barycentric coordinates of T> with respect to ( A + s B+ s C>). A rational triangular Bézier surface is constructed similarly as for rectangular surfaces: <\equation*> s\T\w > (s;A,B,C)>|> (s;A,B,C)>> where \\> are the of the control points (usually positive). Here is the well-known \ example of a teapot model made of \ 32 pieces of tensor product Bézier surfaces of bidegre : <\with|par-mode|center> |bezier_surface_teapot.axl>