RE: ParametricPlot3D is buggy
- To: mathgroup at smc.vnet.net
- Subject: [mg25245] RE: [mg25223] ParametricPlot3D is buggy
- From: "David Park" <djmp at earthlink.net>
- Date: Sun, 17 Sep 2000 04:47:23 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Will,
This does look like a bug in the Mathematica graphics. For some reason
Mathematica's algorithim for automatically picking the PlotRange has
misfired.
plot2 = ParametricPlot3D[{Cos[t]Cos[u], Sin[t]Cos[u], Sin[u]},
{t, 0, 2Pi}, {u, -Pi/2, Pi/2}, PlotPoints -> {7, 3}, PlotRange ->
Automatic];
(a plot but no polyhedron)
FullOptions[plot2, PlotRange]
{{-1.05, 1.05}, {-3.141996211819542*^-15,
2.131357156737179*^-15}, {-1.05, 1.05}}
You will get a proper plot if your choose PlotRange -> All.
Of course, you are using ParametricPlot3D to render polyhedrons by using a
low number of plot points. ParametricPlot3D probably wasn't designed with
that in mind. But PlotRange -> All or a specific PlotRange should solve the
problem.
David Park
djmp at earthlink.net
http://home.earthlink.net/~djmp/
> -----Original Message-----
> From: Will Self [mailto:wself at msubillings.edu]
To: mathgroup at smc.vnet.net
> Can anyone explain this bug that appears in ParametricPlot3D
> in my version of Mathematica 4.0.2 on Windows 2000?
>
> -----------------------------------------------------------
>
> This works fine:
>
> ParametricPlot3D[{Cos[t]Cos[u], Sin[t]Cos[u], Sin[u]},
> {t, 0, 2Pi}, {u, -Pi/2, Pi/2}, PlotPoints -> {8, 3}]
>
> But this doesn't give a picture:
>
> ParametricPlot3D[{Cos[t]Cos[u], Sin[t]Cos[u], Sin[u]},
> {t, 0, 2Pi}, {u, -Pi/2, Pi/2}, PlotPoints -> {7, 3}]
>
>