Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2006
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2006

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: 3D plot with range restricted to non-rectangular region

  • To: mathgroup at smc.vnet.net
  • Subject: [mg66125] Re: 3D plot with range restricted to non-rectangular region
  • From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
  • Date: Sun, 30 Apr 2006 04:21:36 -0400 (EDT)
  • References: <e2v6od$neh$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Hi,

no really but

Off[ParametricPlot3D::pplr]
gr = ParametricPlot3D[{x, y,
h[x, y, 1 - x - y]}, {y, 0, 1}, {x, 0, 1}, DisplayFunction -> Identity];
Show[Graphics3D[
     Cases[gr, p_Polygon /; FreeQ[p, Indeterminate], Infinity]]]

may help you.
Regards
   Jens

David Sanders wrote:
> Hi,
> 
> I want to plot a function whose range is naturally restricted to a
> non-rectangular region:
> 
> h[x_, y_, z_] := Log[x] + Log[y] + Log[z]
> 
> h2[x_, y_] := h[x, y, 1 - x - y]
> 
> Only the region {(x,y): 0<x<1; 0<y<1-x}  is allowed.
> 
> If I try the naive
> Plot3D[h2[x, y], {x, 0, 1}, {y, 0, 1}]
> 
> then I get error messages of the type:
> 
> Plot3D::plnc: h2[x, y] is neither a machine-size real number at {x,
> y}={0.5, \
> 0.5} nor a list of a real number and a valid color directive
> 
> But then it plots the graph anyway.
> 
> I also need contour plots of functions like this.
> 
> Is there a proper way of avoiding these error messages, like making it
> ignore points whenever they contain an illegal operation (here, Log of
> a negative number)?
> 
> Thanks,
> David.
> 


  • Prev by Date: Re: Conditions with Statistical Functions
  • Next by Date: Re: 2D/3D plots scaled to unit of dimension
  • Previous by thread: Re: 3D plot with range restricted to non-rectangular region
  • Next by thread: Re: 3D plot with range restricted to non-rectangular region