Bézier surfaces |
Bézier surfaces are special types of rational surfaces, which use Bernstein bases to represent the polynomial functions. Several types of Bézier surfaces exist.
A rectangular or tensor product Bézier parametric surface is the image of a map of the form
where are the control points, and , are the Bernstein basis elements of degree for the interval .
A rational tensor-product Bézier surface is constructed as follows:
where are the weights of the control points (usually ).
The bidegree of the parametrisation is .
A triangular or simplex Bézier parametric surface is the image of a map of the form
where is the triangle defined by the points , are the control points, and , are the barycentric coordinates of with respect to ().
A rational triangular Bézier surface is constructed similarly as for rectangular surfaces:
where are the weights 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 :