Re: ContourPlot3D and positive contours
- To: mathgroup at smc.vnet.net
- Subject: [mg88300] Re: ContourPlot3D and positive contours
- From: Szabolcs Horvát <szhorvat at gmail.com>
- Date: Thu, 1 May 2008 03:20:02 -0400 (EDT)
- Organization: University of Bergen
- References: <fv9jtb$52h$1@smc.vnet.net>
guerom00 wrote:
> Hello everyone :)
>
> Using the ContourPlot3D, how can I plot only the positive contours (or
> only the negative ones for that matter=85)
> I would imagine an option like this :
>
> ContourPlot3D[f,Contours->{#>0&,10}]
>
> which would plot the first 10 positive contours. But that does not
> exist=85
>
> Right now, I'm plotting the contours of the positive part of my
> function like this :
>
> ContourPlot3D[1/2*(f+Abs[f]),Contours->{10}]
>
> but that's not pretty=85
>
> Is there a better way to do this ?
You could try using RegionFunction. Here's is an example:
ContourPlot[x^3 - 3 y^2 x, {x, -3, 3}, {y, -3, 3},
RegionFunction -> Function[{x, y, f}, f > 0], Contours -> 20]
This should be applicable to 3D as well.