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Dear Jose,<br>
<br>
I think I have had similar error, when importing GMSH mesh into
FreeFEM++, few years ago (although it seems that the error message
might have changed). It turned out that the direction of loop
definition in GMSH was the issue for me. See below my exchange with
FreeFEM++ mailing list.<br>
<br>
Maybe it can be helpful for you.<br>
<br>
Best regards,<br>
Ugis Lacis<br>
Researcher<br>
KTH Mechanics<br>
<br>
------------------------------------------------------------------------------------------------------------------------------------------------------------------<br>
-------- Forwarded Message --------
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">Subject: </th>
<td>Re: [Freefempp] Issue with loading mesh from GMSH.</td>
</tr>
<tr>
<th valign="BASELINE" nowrap="nowrap" align="RIGHT">Date: </th>
<td>Fri, 3 Aug 2018 09:41:29 +0200</td>
</tr>
<tr>
<th valign="BASELINE" nowrap="nowrap" align="RIGHT">From: </th>
<td>Uģis Lācis <a class="moz-txt-link-rfc2396E" href="mailto:ugis.lacis@gmail.com"><ugis.lacis@gmail.com></a></td>
</tr>
<tr>
<th valign="BASELINE" nowrap="nowrap" align="RIGHT">To: </th>
<td>FreeFem mailing list <a class="moz-txt-link-rfc2396E" href="mailto:freefempp@ljll.math.upmc.fr"><freefempp@ljll.math.upmc.fr></a></td>
</tr>
</tbody>
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<br>
<br>
Hi everyone,<br>
<br>
I managed to solve the issue myself. It turned out that the
direction of GMSH loop was surviving till FreeFEM++ and while GMSH
did not complain about anything, FreeFEM++ couldn't use the mesh.
mesh2 could be fixed by changing signs in all lines within the line
loop, i.e.,<br>
change<br>
Line Loop(5) = {18, 19, 20, 12, 7, 8};<br>
to<br>
Line Loop(5) = {-18, -19, -20, -12, -7, -8};<br>
<br>
Maybe this helps to someone at some point.<br>
<br>
Best,<br>
Ugis<br>
<br>
On 02/08/18 15:30, Uģis Lācis wrote:<br>
Dear FreeFEM++ users and developers,<br>
<br>
I have run into an issue which I am unable to solve by myself. I
have been using FreeFEM++ together with GMSH without any problems
for quite some time. Now, however, trying to load a 2D mesh
generated by GMSH, gives me following error:<br>
<br>
Assertion fail : (area>0)<br>
line :281, in file ./include/fem.hpp<br>
<br>
I attach the corresponding geo and msh files of two meshes (mesh1 -
working fine, mesh2 - does not load), as well as edp file for
reading and plotting the mesh.<br>
<br>
I have carefully checked that physical tags are applied correctly, I
have tried exporting both in MSH and MESH (medit) formats, using
GMSH versions 3.06 and 2.16.0, as well as using FreeFEM++ versions
3.560000 and 3.610002, all try has led me to the same behaviour. I
have identified that the issue comes from the surface mesh, if I
export only line mesh (comment out "Physical Surface(11) = {3,4};"
from mesh2.geo and run "gmsh -2 mesh2.geo"), then it loads fine. But
checking the mesh within GMSH, everything seems to be perfectly
fine...<br>
<br>
Do you have any suggestions on how to solve this issue?<br>
<br>
Best regards,<br>
Ugis Lacis<br>
Researcher<br>
KTH Mechanics<br>
------------------------------------------------------------------------------------------------------------------------------------------------------------------<br>
<br>
<br>
<div class="moz-cite-prefix">On 14/05/2020 12:03, Jose Juan Alonso
del Rosario wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAPPcFGa5+PXL4ge9n5uYOtL3RxK6xRO7wVnH7vvBpSTDjsEy0Q@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="ltr">
<div>Dear colleages</div>
<div><br>
</div>
<div>I am trying to build the mesh for a slice with a pentagonal
hole.</div>
<div>GMSH runs properly with good quality tets but when trying
to read it from freefem++ the error is:</div>
<div><br>
</div>
<div>" Bad orientation: The adj border element defined by [ 16
246 ] is oriented in the same direction in element 3922 and
in the element 446 ****** bug in mesh construction?
orientation parameter? <br>
current line = 12 mpirank 1 / 2<br>
</div>
<div>"</div>
<div>Can you give any advice on this?</div>
<div><br>
</div>
<div>Thanks in advance<br>
</div>
<div><br>
</div>
<div>Jose<br>
</div>
<div><br>
-- <br>
<div dir="ltr" class="gmail_signature"
data-smartmail="gmail_signature">
<div dir="ltr">Prof. Dr. Jose Juan Alonso del Rosario<br>
Applied Physics Dept.,
<div>Naval and Oceanic Engineering. </div>
<div>University of Cadiz.<br>
Avda Rep Saharaui s/n. Puerto Real, 11510, Cadiz, Spain<br>
Tlf: +34 956 016054<br>
Fax: +34 956016079<br>
Secretary: +34 956016078<br>
<br>
</div>
<div>"All I wanna say is that they don't really care about
us", Michael Jackson<br>
</div>
</div>
</div>
</div>
</div>
<br>
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<pre class="moz-quote-pre" wrap="">_______________________________________________
gmsh mailing list
<a class="moz-txt-link-abbreviated" href="mailto:gmsh@onelab.info">gmsh@onelab.info</a>
<a class="moz-txt-link-freetext" href="http://onelab.info/mailman/listinfo/gmsh">http://onelab.info/mailman/listinfo/gmsh</a>
</pre>
</blockquote>
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