Build a 3d surface from its explicit equation

Dear All,
i would know if there is way to build in OCC a 3d surface directly from its equation.
I have the explicit equation in the form :
z = f ( x,y)
The domain of x,y variables is rectangle , for example say 10x 10 .
Could share a fragment of code if possible a two levels ?:
1. geometry level to get a Handle(Geom_Surface) and / or
2 topology level to get a TopoDS_Face
Thanks in advance