[Octave-bug-tracker] [bug #33239] Incorrect mesh lines after 'hidden off'

[anonymous]

URL:
  <http://savannah.gnu.org/bugs/?33239>

                 Summary: Incorrect mesh lines after 'hidden off'
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Thu 05 May 2011 07:35:46 PM UTC
                Category: Plotting
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: David O'Neill
        Originator Email: address@hidden
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 3.2.3
        Operating System: GNU/Linux

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Details:

Plotting the unit sphere so that it is bisected in the yz plane (at the edge
of a plot, in the example shown below through x = -1), then specifying 'hidden
off' as follows:


octave-3.2.3:1> [x,y,z] = sphere;
octave-3.2.3:2> mesh(x-1, y, z);
octave-3.2.3:3> axis([-1 1 -1 1 -1 1]);
octave-3.2.3:4> hidden off;
octave-3.2.3:5> print -djpg hemisphere.jpg; %(to include with this report)


leads to three problems 

1) two additional lines, unrelated to the sphere, appear (from the "south
pole" in directions that comprise various resultants of the positive x and z
axes)

2) mesh lines are missing from parts of the great plane of bisection

3) additional mesh lines appear: 

from the "north pole" - lines of longitude" up to, but not including, the
second "line of latitude";

from one of (the two) "lines of longitude" in the bisected plane, - "lines of
latitude", up to, but not including,  the second "line of longitude", of the
two omitted by the bisection. The lines pass directly from the "line of
longitude" that is plotted, to the position of the nodes with the "line of
longitude".

I understand (from a thread in the Nabble forum) that the problem also occurs
with Portable Octave 3.0.0 under windows/cygwin (see
http://octave.1599824.n4.nabble.com/quot-axis-scale-dataspectratio-quot-problem-with-3D-graph-td3491951.html)




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File Attachments:


-------------------------------------------------------
Date: Thu 05 May 2011 07:35:46 PM UTC  Name: hemisphere.jpg  Size: 93kB   By:
None
Image, as noted in the code above, to illustrate the problem
<http://savannah.gnu.org/bugs/download.php?file_id=23355>

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