Re: How to apply EdgeForm to ParametricPlot3D?

*To*: mathgroup at christensen.cybernetics.net*Subject*: [mg1726] Re: [mg1697] How to apply EdgeForm to ParametricPlot3D?*From*: Richard Mercer <richard at seuss.math.wright.edu>*Date*: Fri, 21 Jul 1995 00:06:38 -0400

> Hello. Is it possible to apply the EdgeForm Graphics3D > directive to a surface plot done with ParametricPlot3D? > The Book says nothing to the contrary, but I haven't > found a way of getting it to work (i.e. ParametricPlot3D > *always* draws black edges on the polygons forming the > surface, regardless of EdgeForm directives). Does anybody > know how to do it? > > Thanks in advance, > > Gabriel Actually "The Book" does say something to the contrary in the sense that MeshStyle is an option for Plot3D but not for ParametricPlot3D or Graphics3D. EdgeForm is a Graphics3D primitive. Unfortunately, graphics primitives can never just be thrown naked into graphics commands. (Unless you use calcE! See http://seuss.math.wright.edu/calcE/calcEHome.html or ask for further info.) Anyway, here's one way to "do it". The result is a sphere with red mesh lines instead of black ones. (Nice!) gr = ParametricPlot3D[{Sin[s] Cos[t],Sin[s] Sin[t],Cos[s]},{s,0,Pi},{t,0,2Pi}]; gr1 = Insert[gr,EdgeForm[RGBColor[1,0,0]],{1,1}]; Show[gr1] To see why this works: Short[InputForm[gr],5] Short[InputForm[gr1],8] The Insert command places the EdgeForm primitive at the beginning of the list of polygons. Richard Mercer