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Re: SphericalPlot3D ColorFunction problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg104693] Re: [mg104653] SphericalPlot3D ColorFunction problem
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Sat, 7 Nov 2009 06:47:00 -0500 (EST)
  • Reply-to: hanlonr at cox.net

In the documentation for the options for SphericalPlot3D it gives an example that shows that the ColorFunction for SphericalPlot3D has six arguments

SphericalPlot3D[Abs[Cos[t]],
 {t, 0, Pi}, {p, -Pi, Pi},
 ColorFunction ->
  Function[{x, y, z, t, p, r},
   Hue[Arg[Cos[t]]/(2. Pi)]],
 ColorFunctionScaling -> False]

SphericalPlot3D[Abs[Cos[t]],
 {t, 0, Pi}, {p, -Pi, Pi},
 ColorFunction ->
  (Hue[Arg[Cos[#4]]/(2. Pi)] &),
 ColorFunctionScaling -> False]


Bob Hanlon

---- Porscha Louise McRobbie <pmcrobbi at umich.edu> wrote: 

=============
Hello,

Can anyone explain why the following simple plot is a single color?

SphericalPlot3D[Abs[Cos[t]], {t, 0, Pi}, {p, -Pi, Pi},
  ColorFunction -> Function[{t}, Hue[Arg[Cos[t]]/(2. Pi)]],
  ColorFunctionScaling -> False]

Arg[Cos[t]]/(2. Pi)] should be zero for t<Pi/2, and 0.5 for t>Pi/2, so  
I expect the the upper lobe of the plot to be red (Hue[0]) and the  
lower lobe to be cyan (Hue[0.5]).  Is there something different about  
ColorFunctions in SphericalPlot3D compared with Plot3D?

Any help is greatly appreciated!

Porscha



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