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Re: Q: Varying colors in Plot3D according to Height

• To: mathgroup at smc.vnet.net
• Subject: [mg55436] Re: Q: Varying colors in Plot3D according to Height
• From: Jeff Bryant <jeffb at wolfram.com>
• Date: Wed, 23 Mar 2005 05:34:46 -0500 (EST)
• References: <200503220851.DAA23758@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

   There are a number of ways you can do this.  Using Plot3D, you can 
use the following:

Plot3D[{4 Sin[x] + 4 Cos[y], If[4 Sin[x] + 4 Cos[y] > 1,
     Red, RGBColor[1, 1, 1]]}, {x, 0, 4 Pi}, {y, 0, 4 Pi},
     BoxRatios -> {1, 1, 1/GoldenRatio}, PlotPoints -> 50]

You can get better effects, including easier lighting effects, using 
ParametricPlot3D:

ParametricPlot3D[{x, y, 4 Sin[x] + 4 Cos[y],
    {EdgeForm[], SurfaceColor[If[4 Sin[x] + 4
     Cos[y] > 1, Red, RGBColor[1, 1, 1]]]}}, {x, 0, 4 Pi},
     {y, 0, 4 Pi}, BoxRatios -> {1, 1, 1/GoldenRatio}, PlotPoints -> 50]

-Jeff

--------------
Jeff Bryant
Wolfram Research, Inc.


Mark Coleman wrote:

> I am plotting a three-dimension function using Plot3D. I would like to 
> highlight the portion of the surface whose height exceeds 1.0 a 
> different color or hue than the portion of the surface below 1.0. My 
> attempts at using ColorFunction to do this have been less than 
> aesthetically pleasing, to say the least. Ideally, I'd like the portion 
> below 1.0 to retain the default Mathematica blue shading (I'm using
> Mathematica ver 5.1.1 on a Mac OS X 10.3.8), and perhaps have the portion
> above 1.0 to have a red shading. Any help would be greatly appreciated.
> 
> Thanks,
> 
> -Mark

• References:
  • Q: Varying colors in Plot3D according to Height
    • From: Mark Coleman <mark@markscoleman.com>