Hi, (just returned from holidays...) thank you for the hint with the fields, I will try it that way. I have examined demos/fields.geo. Seems like I have to enter all that field-related stuff by hand. I don't mind to do so, but is there a more elegant way, using the GUI? And can I visualize the defined fields before starting the meshing?
Best regards, Matthias > -----Original Message----- > From: Christophe Geuzaine [mailto:[email protected]] > Sent: Tuesday, December 16, 2008 9:41 AM > To: Zenker, Dr. Matthias > Cc: [email protected] > Subject: Re: [Gmsh] lower limit for characteristic length > > Zenker, Dr. Matthias wrote: > > Of course. Here it is. > > > > BTW, I use gmsh 2.2.6 on a WIN XP SP 2, Pentium 4, 3.2 GHz, > 1.5 GB RAM > > computer. > > > > The default random perturbation factor seems to be a bit > small in your case. The following (increased "-rand" from > "1.e-9" to "1.e-7") > > gmsh small_cl.geo -2 -rand 1.e-7 > > seems to work just fine, but I had to stop it before the end > due to insufficient memory on my laptop. Multiplying all the > element sizes by 3 and using the faster del2d algorithm > > gmsh small_cl.geo -2 -rand 1.e-7 -clscale 3 -algo del2d > > produced a nice mesh with about 23 million triangles. > > > > If I could force gmsh not to ignore the cl of the spline control > > points, it would probably be faster for such a case (if it wouldn't > > crash). Is there a trick to do that? Would it help to put isolated > > points with the desired cl at the desired location? > > You should probably use Fields to fine-tune the element > sizes. There are some examples on the mailing list, as well > as in demos/fields.geo. > > > > > > > Thank you and best regards, > > > > Matthias > > > >> -----Original Message----- > >> From: Christophe Geuzaine [mailto:[email protected]] > >> Sent: Monday, December 15, 2008 1:07 PM > >> To: Zenker, Dr. Matthias > >> Cc: [email protected] > >> Subject: Re: [Gmsh] lower limit for characteristic length > >> > >> Zenker, Dr. Matthias wrote: > >>> Hi there, > >>> > >>> the question remains: is there a lower limit for the > characteristic > >>> length cl, and why does gmsh crash when some points have > a small cl? > >> It shouldn't crash, except when "cl" divided by the overall > >> size of model is getting close to machine accuracy (or more > >> accurately, close to the value of the random pertutbation > >> used in the meshing algorithms, which is 1e-9 by default). > >> > >> Could you send a file that shows the problem? > >> > >> > >>> I would like to add another one: Is it possible that gmsh > >> ignores the > >>> cl of the control points of a spline except for the first > and last > >>> one? If > >> That's what Gmsh does: the cls of the control points are ignored. > >> > >> > >> > >>> so, is there a way to force gmsh to take into account the > cl of the > >>> intermediate points also? > >>> > >>> Best regards, > >>> > >>> Matthias > >>> > >>> > >> -------------------------------------------------------------- > >> ---------- > >>> *From:* [email protected] > [mailto:[email protected]] *On > >>> Behalf Of *Zenker, Dr. Matthias > >>> *Sent:* Monday, November 17, 2008 10:49 AM > >>> *To:* [email protected] > >>> *Subject:* Re: [Gmsh] lower limit for characteristic length > >>> > >>> I was wrong, it crashes also for cl=0.0005 (but after a > >> looong time, > >>> and with a runtime error). > >>> > >>> > >> -------------------------------------------------------------- > >> ---------- > >>> *From:* [email protected] > >> [mailto:[email protected]] *On > >>> Behalf Of *Zenker, Dr. Matthias > >>> *Sent:* Monday, November 17, 2008 10:16 AM > >>> *To:* [email protected] > >>> *Subject:* [Gmsh] lower limit for characteristic length > >>> > >>> Hi, > >>> > >>> I wonder if there is a lower limit for the characteristic > >>> length. I have a rather simple 2D geometry, and if > >> I set the cl > >>> for just two points to 0.0001, gmsh crashes during > >> the meshing > >>> after having given the error message "3 identical > points in > >>> Qtest". The .gmsh-errors file is not written. With > >> cl=0.0005, > >>> this does not happen (but it takes veeery long to > >> compute the mesh). > >>> Best regards, > >>> > >>> Matthias > >>> > >>> > >> ---------------------------------------------------------------- > >>> ERBE Elektromedizin GmbH > >>> Dr.rer.nat. Matthias Zenker > >>> Dipl. Phys. > >>> Grundlagenentwicklung Technologie > >>> Waldhoernlestrasse 17 > >>> D-72072 Tuebingen > >>> Tel.: + 49 (0) 7071 - 755 226 > >>> Fax: + 49 (0) 7071 - 755 5226 > >>> E-Mail: <_mailto:[email protected]_> > >>> URL: _http://www.ERBE-med.de_ > >>> > >>> ---------------------------------------------------------------- > >>> > >>> > >>> > >>> > >>> > >>> ERBE Elektromedizin GmbH > >>> Firmensitz: 72072 Tuebingen > >>> Geschaeftsfuehrer: Christian O. Erbe, Reiner Thede > >>> Registergericht: Stuttgart HRB 380137 > >>> > >>> > >>> > >>> > >>> > >>> > >>> ERBE Elektromedizin GmbH > >>> Firmensitz: 72072 Tuebingen > >>> Geschaeftsfuehrer: Christian O. Erbe, Reiner Thede > >>> Registergericht: Stuttgart HRB 380137 > >>> > >>> > >>> > >>> > >>> > >>> > >>> ERBE Elektromedizin GmbH > >>> Firmensitz: 72072 Tuebingen > >>> Geschaeftsfuehrer: Christian O. Erbe, Reiner Thede > >>> Registergericht: Stuttgart HRB 380137 > >>> > >>> > >>> > >>> > >> > ---------------------------------------------------------------------- > >>> -- > >>> > >>> _______________________________________________ > >>> gmsh mailing list > >>> [email protected] > >>> http://www.geuz.org/mailman/listinfo/gmsh > >> > >> -- > >> Prof. Christophe Geuzaine > >> University of Liege, Electrical Engineering and Computer > >> Science http://www.montefiore.ulg.ac.be/~geuzaine > >> > > > > > _____________________________________________________________________ > > ERBE Elektromedizin GmbH > > Firmensitz: 72072 Tuebingen > > Geschaeftsfuehrer: Christian O. Erbe, Reiner Thede > > Registergericht: Stuttgart HRB 380137 > > > > > > > > > -------------------------------------------------------------- > ---------- > > > > _______________________________________________ > > gmsh mailing list > > [email protected] > > http://www.geuz.org/mailman/listinfo/gmsh > > > -- > Prof. Christophe Geuzaine > University of Liege, Electrical Engineering and Computer Science > http://www.montefiore.ulg.ac.be/~geuzaine > > > _____________________________________________________________________ ERBE Elektromedizin GmbH Firmensitz: 72072 Tuebingen Geschaeftsfuehrer: Christian O. Erbe, Reiner Thede Registergericht: Stuttgart HRB 380137 _______________________________________________ gmsh mailing list [email protected] http://www.geuz.org/mailman/listinfo/gmsh
