<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
</head>
<body bgcolor="#FFFFFF" text="#000000">
Hi Christophe and Gmsh team,<br>
I've been trying to model a simple cube with a cylindrical hole that
is NOT through-going (i.e., its depth is smaller than the depth of
the cube), as shown in the attached picture. The Extrude command
doesn't seem to work since it will extrude both surfaces (exterior
and interior -- hole) at the same time. I know I can define all the
surfaces, surface loops, and volumes manually, but is there a better
way of defining something like this in Gmsh? <br>
<br>
I also tried to use the Compound Volume command by first defining
two volumes from Extrude and then trying to combine them but I'm
getting errors for the Compound Volume visualization (Error: Cannot
evaluate bounds on GRegion Compound) and when I mesh the geometry,
the actual shared interfaces are still existing, although by the
notion of compound from the documentation, the internal interfaces
should be neglected. Here is the geometry file:<br>
<blockquote>// Characteristic length (==> element size)<br>
cl_external = 25;<br>
cl_excavation = 5;<br>
<br>
// External boundaries<br>
Point(1) = {-127, 0.0, -127, cl_external};<br>
Point(2) = {+127, 0.0, -127, cl_external};<br>
Point(3) = {+127, 0.0, +127, cl_external};<br>
Point(4) = {-127, 0.0, +127, cl_external};<br>
Line(1) = {1, 2};<br>
Line(2) = {2, 3};<br>
Line(3) = {3, 4};<br>
Line(4) = {4, 1};<br>
Line Loop(1) = {1, 2, 3, 4};<br>
<br>
// Excavation boundaries<br>
Point(5) = {0.0, 0.0, 0.0, cl_excavation};<br>
Point(6) = {19.05, 0.0, 0.0, cl_excavation};<br>
Point(7) = {0.0, 0.0, 19.05, cl_excavation};<br>
Point(8) = {-19.05, 0.0, 0.0, cl_excavation};<br>
Point(9) = {0.0, 0.0, -19.05, cl_excavation};<br>
Circle(5) = {6, 5, 7};<br>
Circle(6) = {7, 5, 8};<br>
Circle(7) = {8, 5, 9};<br>
Circle(8) = {9, 5, 6};<br>
Line Loop(2) = {5, 6, 7, 8};<br>
<br>
//Using compound volumes<br>
Plane Surface(1) = {1};<br>
out1[] = Extrude {0.0, 76.2, 0.0}{Surface{1};};<br>
<br>
Plane Surface(2) = {1};<br>
out2[] = Extrude {0.0, -76.2, 0.0}{Surface{2};};<br>
<br>
Compound Volume(3) = {1, 2};<br>
</blockquote>
<br>
I also tried to create the geometry in CAD software and imported it
as iges, brep or step formats but for reason the hole is not there
completely. See for instances the iges file attached.<br>
<br>
Can you kindly shed some light here? Am I doing something wrong? Or
are there Gmsh tricks/commands that I can use to achieve my goal?<br>
<br>
Thank you,<br>
Omid<br>
<br>
<pre class="moz-signature" cols="72">--
Omid Mahabadi, Ph.D.
Geomechanica, Inc.
<a class="moz-txt-link-freetext" href="http://www.geomechanica.com/">http://www.geomechanica.com/</a>
Tel : +1-647-478-9767
Cell: +1-416-824-2408
</pre>
</body>
</html>