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Hi Oliver,<br>
You seem to be right and I may have to follow the approach that I
didn't want to pursue initially: manually adding most of the
entities. <br>
<br>
Thanks,<br>
Omid<br>
<br>
<div class="moz-cite-prefix">On 14-09-02 05:57 PM, Oliver Willekens
wrote:<br>
</div>
<blockquote
cite="mid:CAEqQaNCfKFGhK=1J=haYM8zHkbW384MxjLN6UGWxkZ-_dMBLkg@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>
<div>
<div>
<div>If you change the lines in your file after ```//Using
compound volumes``` to the ones from my previous mail,
you should get the same result. <br>
</div>
From the looks of your screenshot, it would seem the
bottom half is not defined as a volume. I got it
automatically as a volume though, from the extrusion
command. Odd.<br>
<br>
</div>
After my first reply, I've looked more into those GRegion
Compound errors, and have seen that they're a recurring
problem on the mailing list when trying to use Compound
Volume, but so far no solutions have been given/found. I'm
hoping an answer will come one day though.<br>
<br>
</div>
The only other solution I see (at the moment, due to the
failing compound volumes) to ensure the mesh is "continuous"
across the interface, is simply not to have the interface at
all. So manually fleshing out the geometry, point by point,
line by line (okay, you can extrude some points and lines of
course) and then definining a single volume by selecting the
faces of the cylinder and the box. So this comes back to your
original question:<br>
>> 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>
</div>
At the moment: no. Unless you don't mind that artificial
interface.<br>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">2014-09-02 21:13 GMT+02:00 Omid
Mahabadi <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:omid.mahabadi@geomechanica.com"
target="_blank">omid.mahabadi@geomechanica.com</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> Hi Oliver,<br>
Thanks for your response. I had also tried the variation
that you sent me. The issue is that I don't want to have
the flat surface that is interfacing the two volumes.
I'd like the mesh to be continuous across that
interface.<br>
<br>
Also, when following your suggestion, I still cannot get
the same exact mesh as you did. Please see the attached
screenshot. <br>
<br>
Is there any other thoughts on how to get the results
I'm aiming for?<br>
<br>
Thank you,<br>
Omid
<div>
<div class="h5"><br>
<br>
<div>On 14-08-28 06:34 PM, Oliver Willekens wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>
<p style="margin:1.2em 0px!important">You
could delete the volume of the cylinder
you’ve created by means of extrusion and
then delete one of the cylinder’s flat
surfaces using the <code
style="font-size:0.85em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px
0.15em;padding:0px
0.3em;white-space:pre-wrap;border:1px
solid
rgb(234,234,234);background-color:rgb(248,248,248);border-radius:3px;display:inline">Delete</code>
command. However, it won’t give you what you
want, because the box “holding the cylinder”
will be unaware of the presence of the
cylindrical hole.</p>
<p style="margin:1.2em 0px!important">I tried
this:</p>
<pre style="font-size:0.85em;font-family:Consolas,Inconsolata,Courier,monospace;font-size:1em;line-height:1.2em;margin:1.2em 0px"><code style="font-size:0.85em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px 0.15em;padding:0px 0.3em;white-space:pre-wrap;border:1px solid rgb(234,234,234);background-color:rgb(248,248,248);border-radius:3px;display:inline;white-space:pre-wrap;overflow:auto;border-radius:3px;border:1px solid rgb(204,204,204);padding:0.5em 0.7em;display:block!important;display:block;padding:0.5em;color:rgb(51,51,51);background:none repeat scroll 0% 0% rgb(248,248,255)">Plane Surface(1) = {1, 2}; // square minus the circle
out1[] = Extrude {0.0, 76.2, 0.0}{Surface{1};};
Plane Surface(2) = {1};
out2[] = Extrude {0.0, -76.2, 0.0} {Surface{2};};
</code></pre>
<p style="margin:1.2em 0px!important">Which
results in the 2D mesh you find in the
attachment. Perhaps this is what you’re
looking for?</p>
<p style="margin:1.2em 0px!important">I also
tried combining those two volumes using <code
style="font-size:0.85em;font-family:Consolas,Inconsolata,Courier,monospace;margin:0px
0.15em;padding:0px
0.3em;white-space:pre-wrap;border:1px
solid
rgb(234,234,234);background-color:rgb(248,248,248);border-radius:3px;display:inline">Compound
Volume(4) = {out1[1], out2[1]};</code>,
but like you, I got GRegion Compound errors.
Probably some basic restriction from
triangulations I’m overlooking. This only
means your 3D meshes will be clearly stopped
at a flat interface about half-way through
those two boxes, but you’ll still have a 3D
mesh. I was hoping that the Compound Volume
would make some tetras across this boundary
though… But with the above lines, you’ll
have a working mesh.</p>
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dmUgYSB3b3JraW5nIG1lc2guPGJyPgo8ZGl2Pjxicj48L2Rpdj4="
style="min-height:0;font-size:0em;padding:0;margin:0"></div>
</div>
</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">2014-08-28 17:08
GMT+02:00 Omid Mahabadi <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:omid.mahabadi@geomechanica.com"
target="_blank">omid.mahabadi@geomechanica.com</a>></span>:<br>
<blockquote class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex">
<div 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<span><font color="#888888"><br>
<br>
<pre cols="72">--
Omid Mahabadi, Ph.D.
Geomechanica, Inc.
<a moz-do-not-send="true" href="http://www.geomechanica.com/" target="_blank">http://www.geomechanica.com/</a>
Tel : <a moz-do-not-send="true" href="tel:%2B1-647-478-9767" value="+16474789767" target="_blank">+1-647-478-9767</a>
Cell: <a moz-do-not-send="true" href="tel:%2B1-416-824-2408" value="+14168242408" target="_blank">+1-416-824-2408</a>
</pre>
</font></span></div>
<br>
_______________________________________________<br>
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target="_blank">gmsh@geuz.org</a><br>
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href="http://www.geuz.org/mailman/listinfo/gmsh"
target="_blank">http://www.geuz.org/mailman/listinfo/gmsh</a><br>
<br>
</blockquote>
</div>
<br>
<br clear="all">
<br>
-- <br>
Oliver Willekens<br>
PhD Student <br>
<a moz-do-not-send="true"
href="https://lcp.elis.ugent.be/"
target="_blank"><img moz-do-not-send="true"
src="http://lcp.elis.ugent.be/sites/lcp.elis.ugent.be/files/logo.jpg"
alt="LCP group logo"
style="float:left;margin-right:20px;margin-top:20px"></a>
<p style="margin-top:20px"> Liquid Crystals
& Photonics Group <br>
Sint- Pietersnieuwstraat 41 <br>
9000 Gent <br>
Phone: <a moz-do-not-send="true"
href="tel:%2B32%209%20264.89.51"
value="+3292648951" target="_blank">+32 9
264.89.51</a> </p>
</div>
</blockquote>
<br>
<pre cols="72">--
Omid Mahabadi, Ph.D.
Geomechanica, Inc.
<a moz-do-not-send="true" href="http://www.geomechanica.com/" target="_blank">http://www.geomechanica.com/</a>
Tel : <a moz-do-not-send="true" href="tel:%2B1-647-478-9767" value="+16474789767" target="_blank">+1-647-478-9767</a>
Cell: <a moz-do-not-send="true" href="tel:%2B1-416-824-2408" value="+14168242408" target="_blank">+1-416-824-2408</a>
</pre>
</div>
</div>
</div>
</blockquote>
</div>
<br>
<br clear="all">
<br>
-- <br>
Oliver Willekens<br>
PhD Student <br>
<a moz-do-not-send="true" href="https://lcp.elis.ugent.be/"
target="_blank"><img moz-do-not-send="true"
src="http://lcp.elis.ugent.be/sites/lcp.elis.ugent.be/files/logo.jpg"
alt="LCP group logo"
style="float:left;margin-right:20px;margin-top:20px"></a>
<p style="margin-top:20px">
Liquid Crystals & Photonics Group <br>
Sint- Pietersnieuwstraat 41 <br>
9000 Gent <br>
Phone: +32 9 264.89.51
</p>
</div>
</div>
</blockquote>
<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>
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