Re: How To invert ColorFunction

• To: mathgroup at smc.vnet.net
• Subject: [mg106738] Re: [mg106719] How To invert ColorFunction
• From: "Eric G" <eric.phys at gmail.com>
• Date: Fri, 22 Jan 2010 05:38:37 -0500 (EST)
• References: <201001211131.GAA20635@smc.vnet.net>

```Hi Vladimir,
try this:

c4 = 1;

z4[rho_, theta_] := rho^2*Cos[2*theta];

min = -1 (* the minimun in your z axis*);
max = 1   (*...maximun ....*);

RevolutionPlot3D[c4*z4[rho, theta], {rho, 0, 1}, {theta, 0, 2*Pi},
ColorFunction -> (ColorData["Rainbow"][(#3 - min)/(max - min)] &),
ColorFunctionScaling -> False]

----- Original Message -----
From: "Vladimir" <svetlana_47 at yahoo.de>
To: <mathgroup at smc.vnet.net>
Sent: Thursday, January 21, 2010 3:31 AM
Subject: [mg106738] [mg106719] How To invert ColorFunction

> Hi everybody,
>
> I am plotting Zernike-Polynomials like this:
>
> ---------
> c4 = 1;
>
> z4[rho_, theta_] := rho^2*Cos[2*theta]
>
> RevolutionPlot3D[c4*z4[rho, theta], {rho, 0, 1}, {theta, 0, 2*Pi},
> ColorFunction -> "Rainbow"]
> ---------
>
> To be able to compare the plot to measured data from an
> interferometer, I would like to invert the Rainbow colouring, that is
> red at the bottom and blue on top. However, I can't find to work this
> out. Does anyone know how to do this?
>
> Thank you,