Hi, I'd like to plot the surface of a function such as exp(x*y) only for the (x,y)'s in the unit ball B = \{(x,y) \in \mathbb{R}^2 : x^2+y^2 \le 1\}. I do not want to set the value of the function outside B to some particular value (e.g. 0). Do you know if there exists some pstricks package that can make this ? Thanks, elef