<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
</head>
<body>
<p> Dear developers and users,</p>
<p><br>
</p>
<p><b>*** The goal</b></p>
<p>We want to create a checkerboard model to run some resolution
studies with our FE software.</p>
<p>For that, we construct a geometry consisting of a large box which
includes an arbitrary amount of small boxes at an arbitrary
position using the OpenCascade kernel features.</p>
<p>Subsequently, we add some arbitrary points to that geometry which
we need to be part of the 3D mesh, i.e. which should be contained
in mesh as mesh vertices.</p>
<p>In case of these points are located within any face or volume of
the geometry, `<code>Point | Curve { <var>expression-list</var> }
In Surface { <var>expression</var> };`</code> or `<code>Point |
Curve { <var>expression-list</var> } In Volume { <var>expression</var>
};` </code>does it's job very well!</p>
<p>However, if points are <span class="gt-baf-term-text"><span
class="gt-baf-cell gt-baf-word-clickable">accidentally located
on edges, </span></span>making them part of the mesh vertex
list is not possible as unfortunately there is no `<code>Point |
Curve { <var>expression-list</var> } In Line { <var>expression</var>
};` </code> so far.</p>
<p><br>
</p>
<p><b>*** The workaround</b></p>
<p>We tried to force Gmsh adding that points to the edges by
defining small lines which we add to the surface that belongs to
the respective edges.</p>
<p>-> Please have a look on the attached MWE, that illustrates
our approach.</p>
<p><br>
</p>
<p><b>*** The problem<br>
</b></p>
<p>We are controlling the cell sizes by using a combination of
filter.</p>
<p>When changing the scales of our geometry or changing the
parameter set of our filters, meshing sometimes fails without any
- at least for us - understandable reason.</p>
<p>-> Please try using line 6 instead of line 5 in the MWE.</p>
<p><br>
</p>
<p>Does somebody have a hint how to fix that?</p>
<p>Or, does somebody have an even better workaround for subsequently
adding points to edges?<br>
<b></b></p>
<p><br>
Best regards,<br>
Mathias<br>
<br>
ps: We are using Gmsh 4.5.6.</p>
<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>
</body>
</html>