[Gmsh] lower limit for characteristic length

[Zenker, Dr. Matthias]

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.

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?

Thank you and best regards,

Matthias

> -----Original Message-----
> From: Christophe Geuzaine [mailto:cgeuzaine at ulg.ac.be] 
> Sent: Monday, December 15, 2008 1:07 PM
> To: Zenker, Dr. Matthias
> Cc: gmsh at geuz.org
> 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:* gmsh-bounces at geuz.org [mailto:gmsh-bounces at geuz.org] *On
> >     Behalf Of *Zenker, Dr. Matthias
> >     *Sent:* Monday, November 17, 2008 10:49 AM
> >     *To:* gmsh at geuz.org
> >     *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:* gmsh-bounces at geuz.org 
> [mailto:gmsh-bounces at geuz.org] *On
> >         Behalf Of *Zenker, Dr. Matthias
> >         *Sent:* Monday, November 17, 2008 10:16 AM
> >         *To:* gmsh at geuz.org
> >         *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:Matthias.Zenker at ERBE-med.de_>
> >         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
> > 
> > 
> > 
> > 
> ----------------------------------------------------------------------
> > --
> > 
> > _______________________________________________
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> > gmsh at geuz.org
> > 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

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