Travis Thompson wrote:
Dave,
I certainly will. I checked the options for the 3d algorithm; they
have been set to Tetgen + Delauney, so this has been the one that was
crashing all along. I tried changing it to Netgen for grins - Gmsh
did not crash but the message console complained with about 200 lines
of:
"Info : WARNING: Intersecting elements<Number> and <Number>"
The files that are attached:
plainGeom.geo : The naked geometry
GeomWithVolumeElement.geo: The geometry where the ambient box has
been selected as the 'volume' and the interior object has been
selected as the 'hole'
Surfaces 3 and 11 overlap in your model. So there should in fact be no
hole in your volume, but 2 separate volumes: see attached file.
Note: it is a bit difficult to see that the interior object is closed
as the top surface of the interior object is coplanar with the
bounding box.. but if you click around you can see that the top plane
'closing off' the interior object is indeed there :)
I appreciate your help!
-Travis Thompson
Graduate Student
Dept. of Mathematics, Texas A&M University
On Wed, Oct 29, 2008 at 8:37 AM, David Colignon
<[EMAIL PROTECTED]> wrote:
Hi Travis,
solution a) should have worked. Can you send us your .geo file to check ?
And can you try with with the Tetgen 3D meshing algorithm instead of netgen
?
Cheers,
Dave
--
David Colignon, Ph.D.
Collaborateur Logistique du F.R.S.-FNRS
CÉCI - Consortium des Équipements de Calcul Intensif
ACE - Applied & Computational Electromagnetics
Sart-Tilman B28
Université de Liège
4000 Liège - BELGIQUE
Tél: +32 (0)4 366 37 32
Fax: +32 (0)4 366 29 10
WWW: http://hpc.montefiore.ulg.ac.be/
Agenda: http://www.google.com/calendar/embed?src=david.colignon%40gmail.com
Travis Thompson wrote:
Hello. I have been working with Gmsh for a finite elements project at
Texas A&M university in college station, tx.
I am new to Gmsh and have been stuck on a particular problem for a
while now; I was hoping maybe someone could shed some light on it.
The setup is fairly simple. I have a 3 dimensional rectangle which
completely contains another 3 dimensional object.
The object inside the box is completely closed; i will refer to this
object as Object A. If I attach a volume element to object A and mesh
the box + object A everything works wonderfully. I get a nice 2d mesh
on the bounding box and a nice 3d mesh inside object A.
The problem is that I need a 3d mesh inside the bounding box and i
want *no mesh* in the interior of object A (that is, I want to mesh
the complement of Object A with respect to the bounding box).
What I have tried:
a) I have tried attaching a volume element to the ambient bounding box
and selecting Object A as 'a hole'
b) I have tried attaching a volume element to the bounding box and a
volume element to Object A with the intention of Deleting the volume
element attached to object A *after* computing the mesh.
However both (a) and (b) lead to gmsh crashing (same error on both
windows and Linux versions)
The error is:
----------------------------
Assertion Failed!
Program: c:\program files\gmsh-2.2.4-Windows\gmsh.exe
File: tetgen.cxx
Line: 22506
Expression: matchflag == true
---------------------------
I would imagine that what I am trying to do is quite basic; ie:
meshing the complement of an object inside an ambient object. I have
been through the documentation but due to my lack of familiarity with
Gmsh I have failed to figure out a method.
If anyone can shed any light on this I would greatly appreciate it!
Thank you in advance!
-Travis Thompson
Graduate Student
Dept of Mathematics, Texas A&M University
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Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine
Point(1) = {-20, 20, 0, 1};
Point(2) = {20, 20, 0, 1};
Point(3) = {20, -20, 0, 1};
Point(4) = {-20, -20, 0, 1};
Point(5) = {-20, 20, 10, 1};
Point(6) = {20, 20, 10, 1};
Point(7) = {20, -20, 10, 1};
Point(8) = {-20, -20, 10, 1};
Point(9) = {10, 10, 10, 1};
Point(10) = {-10, 10, 10, 1};
Point(11) = {10, -10, 10, 1};
Point(12) = {-10, -10, 10, 1};
Point(13) = {3, 3, 5.5, 1};
Point(14) = {-4.071067812, 3, 5.5, 1};
Point(15) = {3, -4.071067812, 5.5, 1};
Point(16) = {-4.071067812, -4.071067812, 5.5, 1};
Point(17) = {-0.535533906, -0.535533906, 5.5, 1};
Point(18) = {-0.535533906, -0.535533906, 0.5, 1};
Line(1) = {1, 2};
Line(2) = {2, 3};
Line(3) = {3, 4};
Line(4) = {4, 1};
Line(5) = {2, 6};
Line(6) = {6, 5};
Line(7) = {5, 1};
Line(8) = {7, 6};
Line(9) = {5, 8};
Line(10) = {8, 7};
Line(11) = {7, 3};
Line(12) = {4, 8};
Line(13) = {9, 10};
Line(14) = {10, 12};
Line(15) = {12, 11};
Line(16) = {11, 9};
Line(17) = {13, 14};
Line(18) = {14, 16};
Line(19) = {16, 15};
Line(20) = {15, 13};
Line(21) = {13, 9};
Line(22) = {14, 10};
Line(23) = {16, 12};
Line(24) = {15, 11};
Circle(25) = {15, 17, 18};
Circle(26) = {18, 17, 14};
Circle(27) = {16, 17, 18};
Circle(28) = {18, 17, 13};
Line Loop(1) = {1, 2, 3, 4};
Plane Surface(1) = {1};
Line Loop(2) = {1, 5, 6, 7};
Plane Surface(2) = {2};
Line Loop(3) = {8, 6, 9, 10};
Plane Surface(3) = {3};
Line Loop(4) = {10, 11, 3, 12};
Plane Surface(4) = {4};
Line Loop(5) = {12, -9, 7, -4};
Plane Surface(5) = {5};
Line Loop(6) = {11, -2, 5, -8};
Plane Surface(6) = {6};
Line Loop(7) = {-21, 17, 22, -13};
Plane Surface(7) = {7};
Line Loop(8) = {22, 14, -23, -18};
Plane Surface(8) = {8};
Line Loop(9) = {23, 15, -24, -19};
Plane Surface(9) = {9};
Line Loop(10) = {24, 16, -21, -20};
Plane Surface(10) = {10};
Line Loop(11) = {13, 14, 15, 16};
Plane Surface(11) = {11};
Line Loop(12) = {25, -27, 19};
Ruled Surface(12) = {12};
Line Loop(13) = {25, 28, -20};
Ruled Surface(13) = {13};
Line Loop(14) = {28, 17, -26};
Ruled Surface(14) = {14};
Line Loop(15) = {26, 18, 27};
Ruled Surface(15) = {15};
Delete {
Surface{3};
}
Plane Surface(29) = {3, 11};
Surface Loop(30) = {1, 2, 6, 4, 29, 5, 8, 7, 10, 9, 12, 13, 14, 15};
Volume(31) = {30};
Surface Loop(32) = {11, 9, 8, 7, 10, 13, 12, 15, 14};
Volume(33) = {32};
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