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Dear developers and
users,<br>
<br>
<b>*** The problem</b><br>
our group wants to
use Gmsh for setting up meshes for simulation of geophysical data.<br>
Therefore we need to
create surfaces which are bounded by a circle or rectangular curve
and that contain some topographic information (from given point
cloud) in the “interior” part.<br>
The given points
have to be part of the resulting mesh.<br>
<br>
Defining a Curve
Loop from piece-wise splines (or just Lines) and adding all the
points to the surface leads to undesired “topographic features”
in the area between the boundary and the point cloud in the
resulting
mesh.<br>
<i>See
surface_using_points.geo</i><br>
<br>
Furthermore, by
refining the mesh by splitting, one can see that the mesh around the
points added is not flat/smooth anymore.<br>
<i>See mesh_issue.png</i><br>
<br>
So we separately
defined a surface of the interior part by defining a surrounding
spline curve, which provides a "nice" mesh for that part.<br>
<i>See
surface_splitted.geo</i><br>
<br>
Now we need to
obtain a flat surface that is bounded by the outermost rectangular
curve and the spline curve to obtain a coherent surface.<br>
We played around
with ThruSection (hoping that this is the most promising way to go)
but facing the following problems:<br>
<br>
1)<br>
<i>Curve Loop(50) =
{out_spl[]};</i><i><br>
</i><i>
Wire(1) = {1};</i><i><br>
</i><i>
Wire(2) = {30};</i><i><br>
</i><i>
ThruSections{1, 2}</i><br>
→ Here we get an
Error, that OpenCASCADE can’t find the Curve Loop from splines<br>
<br>
So we neglect the request for a rectangular outermost boundary an
tried<br>
2)<br>
<i>Spline(1) = {1:4,
1};</i><i><br>
</i><i>
Curve Loop(50) =
{1};</i><i><br>
</i><i>
Wire(1) = {1};</i><i><br>
</i><i>
Wire(2) = {30};</i><i><br>
</i><i>
ThruSections{1, 2}</i><br>
→ now Wire(1) can
be created from Spline(1) but the resulting mesh is somehow twisted
(although enjoyable flat …)<br>
<br>
<br>
<b>*** The question(s)</b><br>
Can our approach be
used at all?<br>
→ we definitely
want to avoid playing around with meshes externally like:
<a class="moz-txt-link-freetext" href="http://onelab.info/pipermail/gmsh/2018/012591.html">http://onelab.info/pipermail/gmsh/2018/012591.html</a><br>
<br>
If so – how? <br>
Or is there a more
promising way to attack our problem?<br>
<br>
Best regards,<br>
Mathias<br>
<br>
ps: We are using
Gmsh 4.3.0.<br>
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<pre class="moz-signature" cols="72">--
Dr. Mathias Scheunert
Institute of Geophysics and Geoinformatics, TU Bergakademie Freiberg
Gustav-Zeuner-Str. 12, D-09596 Freiberg
Tel.: +493731393630</pre>
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