How do I add a color bar to a 3D plot?

Question

I tried

Plot3D[Exp[-x^2 - y^2], {x, -2, 2}, {y, -2, 2},
 ColorFunction -> (ColorData["TemperatureMap"][#3] &),
 PlotLegends -> Automatic]

in an attempt to add a colorbar legend to the plot, but this did not work. It did work here:

DensityPlot[Exp[-x^2 - y^2], {x, -2, 2}, {y, -2, 2},
 ColorFunction -> "SunsetColors",
 PlotLegends -> Automatic]

Any suggestions in how I can get it to work in the first bit of code?

Thanks.

Answer 1

A little twisted, and needs some generalisation:

<< PlotLegends`;
c = ColorData["TemperatureMap"];
s := Plot3D[Exp[-x^2 - y^2], {x, -2, 2}, {y, -2, 2},  ColorFunction -> (c[#3] &), 
            ImageSize -> {300, 300}];
k = ShowLegend[ s /. Plot -> DensityPlot, {c[1 - #1] &, 10, " 1", " 0",  
              LegendPosition -> {1.1, -.4}, LegendShadow -> None}] /.  
              Graphics[{_, b_}, ___] :> Graphics[b, ImageSize -> 50];
GraphicsGrid[{{s, k}}]