[R] 3D plot with it's quadratic approximation superimposed in same plot

[Megh Dal]

Dear all, I would like to draw a 3D plot as shown here http://en.wikipedia.org/wiki/File:NaturalLogarithmAll.png, for this function "f = exp[ 1 - x^2 - y^2]" (this function is some arbitrary!). I am aware of different 3D plotting system in R, however it would be great if I can get that kind of "soft look" (this will help me to make a good-looking presentation.)

Additionally, I want to superimpose the Quadratic approximation (at some arbitrary point) of that function, on the top of the same plot. Can somebody help me to achieve that?

Thanks,