Can an arrow be drawn on a 3D plot?

*To*: mathgroup at smc.vnet.net*Subject*: [mg81253] Can an arrow be drawn on a 3D plot?*From*: chuck009 <dmilioto at comcast.com>*Date*: Tue, 18 Sep 2007 00:30:03 -0400 (EDT)

The code below draws a surface and a contour over that surface. I'd like to show the direction of the contour with arrows. Looks like Arrow only works in 2D. Any way to draw an arrow lying on a 3-D surface? Ideally, I'd like to place say 2 arrows on the green contour on the red surface showing the direction (of integration). f[z_] := z; iSurface = ParametricPlot3D[ {Re[z], Im[z], Im[f[z]]} /. z -> r*Exp[I*t], {r, 0, 5}, {t, -Pi, Pi}, PlotStyle -> Red]; traceC1 = ParametricPlot3D[ {Re[z], Im[z], Im[f[z]]} /. z -> 2*Exp[I*t], {t, 0, 2*Pi}, PlotStyle -> {Darker[Green], Thickness[0.004]}]; Show[{iSurface, traceC1}, PlotRange -> {{-7, 7}, {-7, 7}, {-7, 7}}, BoxRatios -> {1, 1, 1}, ImageSize -> {500, 500}]

**Follow-Ups**:**Re: Can an arrow be drawn on a 3D plot?***From:*Gianluca Gorni <gianluca.gorni@dimi.uniud.it>