Re: Export Plot3D as text

• To: mathgroup at smc.vnet.net
• Subject: [mg112937] Re: Export Plot3D as text
• From: Fred Klingener <gigabitbucket at BrockEng.com>
• Date: Wed, 6 Oct 2010 03:17:37 -0400 (EDT)
• References: <i8c8r0\$g68\$1@smc.vnet.net>

```On Oct 4, 6:04 am, Laura Elizabeth McMullen
<mcmul... at science.oregonstate.edu> wrote:
> Hi all-
>
> I have functions I am plotting in 3D in Mathematica, defining ranges
> of values for two of the variables in the function with the Plot3D
> command.  I would like to reproduce these plots in another program,
> but am having difficulty exporting the data in a useful format.  I
> would like the data to be lists of numerical data, but when I export
> the data as text, the file is huge.  Any suggestions?  Thanks for your
> help.

There are probably very terse and elegant ways to get this, but I
usually have to start with brute force. Here's a Plot3D from the doc
center:

p = Plot3D[Sin[x + y^2], {x, -3, 3}, {y, -2, 2}]

This shows the structure, a GraphicsComplex inside a Graphics3D:

p // FullForm

You can look at the basic structure with

{Graphics3D, 2, 11}

p[[1]] is the GraphicsComplex and p[[2]] is the Option list for the
Graphics3D.

Looking at the GC:

In[19]:= {Head[#], Length[#], Depth[#]} & /@ p[[1, 1 ;; 3]]

Out[19]= GraphicsComplex[{List, 3372, 3}, {List, 2, 9}, {Rule, 2, 4}]

So the simplest useful thing you probably want to export is the
surface node list p[[1, 1]], but connectivity and vertex normals are
in 2;;3 if you need refinement.

p[[1, 1]] can be 'huge,' but as a List, it's a lot easier to handle
than a text file.

Hth,
Fred Klingener

```

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