Drawing specific contours in a 3D Surface Plot?

*To*: mathgroup at smc.vnet.net*Subject*: [mg46002] Drawing specific contours in a 3D Surface Plot?*From*: Carsten Aulbert <carsten at welcomes-you.com>*Date*: Mon, 2 Feb 2004 05:20:48 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Hi, is it possible to create a 3d plot of a smooth function f[x,y] (e.g. via Plot3D[...]) and mark specific contour levels in this plot? To add some flesh: f[t_]:= Exp[-t/2]; g[u_,v_,w_]:=BetaRegularized[u, v + 1, w - v]; Plot3D[g[f[x], y,200], {x,0,10}, {y,0,200}] In this plot (with Mesh->False and increased PlotPoints) I'd like to mark the contours at 0.5, 0.5+/- 0.3413. Is this possible? Thanks for any help/link Carsten