Services & ResourcesWolfram ForumsMathGroup Archive

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

Re: A 3D Plot Query

• To: mathgroup at smc.vnet.net
• Subject: [mg94353] Re: A 3D Plot Query
• From: "David Park" <djmpark at comcast.net>
• Date: Thu, 11 Dec 2008 03:43:07 -0500 (EST)
• References: <31362096.1228736527369.JavaMail.root@m02> <200812091159.GAA20944@smc.vnet.net> <31958869.1228906532926.JavaMail.root@m02>

Needs["Presentations`Master`"]

With[
 {a = 1},
 Draw3DItems[
  {Opacity[.5, Brown], 
   ParametricDraw3D[{r Cos[\[Theta]], r Sin[\[Theta]], 
     2 - r^2}, {\[Theta], 0, \[Pi]/2}, {r, 0, a}, 
    PlotPoints -> {30, 10},
    Mesh -> None,
    MaxRecursion -> 3],
   Opacity[1, Black],
   DrawArrow3DAxes[{0, 0, 1}, 1, .1],
   VerticalText3D["x", {1.2 a, 0, 2 - a^2}, 0, {.1, .1}],
   VerticalText3D["y", {0, 1.2 a, 2 - a^2}, 90 \[Degree], {.1, .1}],
   VerticalText3D["z", {0, 0, 2.1}, 90 \[Degree], {.1, .1}],
   VerticalText3D["a", {0, a/2, 2 - .9 a^2}, 90 \[Degree], {.1, .1}]},
  NeutralLighting[.0, .5, .1],
  NiceRotation,
  PlotRange -> {{-.2 a, 1.4 a}, {-.2 a, 1.4 a}, All},
  ViewPoint -> {5, 5, 3},
  BoxRatios -> Automatic,
  Boxed -> False,
  PlotLabel -> Style[z == 2 - Sqrt[x^2 + y^2], 16]]
 ]


David Park
djmpark at comcast.net
http://home.comcast.net/~djmpark/  




From: Murray Eisenberg [mailto:murray at math.umass.edu] 


Another "for engineers and scientists" version of a graph -- and not 
what the poster requested.  As I understand the query, what is desired 
is the positive semi-axes shown emanating from the origin, with z up, x 
forward, and y to the right (roughly).  No frame.

David Park wrote:
> Sid,
> 
> Not silly at all.
> 
> Use cylindrical coordinates and ParametricPlot3D to get a surface with a
> circular base.
> 
> Use the ViewPoint option to get the x and y axes in the position you want.
> 
> With[{a = 5},
>  ParametricPlot3D[{r Cos[\[Theta]], r Sin[\[Theta]], 
>    2 - r^2}, {\[Theta], 0, 2 \[Pi]}, {r, 0, a},
>   PlotPoints -> {30, 10},
>   MaxRecursion -> 3,
>   AxesLabel -> {"x", "y", "z"},
>   ViewPoint -> {5, 5, 3},
>   BoxRatios -> {1, 1, 1}]
>  ]
> 
> 
> David Park
> djmpark at comcast.net
> http://home.comcast.net/~djmpark/  
> 
> 
> From: pcoords29 at gmail.com [mailto:pcoords29 at gmail.com] 
> 
> 
> Hi,
> 
> This may sound silly, but I can't get it to work. (I'm using v 6.0)
> 
> How do I get my 3D plots look as given in textbooks, ie. with the y-
> axis pointing to the right, the z-axis up and x-axis pointing out of
> the paper/screen ( showing the first octant)?  I mean the kind of
> plots one draws on paper when working out surface integrals  in
> Calculus classes.
> 
> If this is of any help, I'd like to get the plot of  the paraboloid
> 
>  z = 2-(x^2+y^2),  as given in Fig. 10-10  of  Spiegel's Advanced
> Calculus, Schaum Series.
> 
> I tried
> 
>         Plot3D[2 - (x^2 + y^2), {x, -a, a}, {y, -a, a}],
> 
> with various values of a. Unfortunately, none of them look like the
> traditional cap-shaped paraboloid.
> 
> Thanks for any help.
> 
> Sid.
> 
> 
> 
> 
> 
> 

-- 
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305

• References:
  • RE: A 3D Plot Query
    • From: "David Park" <djmpark@comcast.net>