[Gmsh] meshing differences between version 1.65.0 and 2.0.4
Daniel Wheeler
daniel.wheeler at nist.gov
Tue Mar 20 18:40:29 CET 2007
Thanks for the prompt reply.
On Mar 20, 2007, at 5:09 PM, David Colignon wrote:
> Hi Daniel,
>
> yes, there are some differences in the default treatment of the
> characteristic lengths ( lc ) between version 1.65 and 2.04.
> In version 2 we added the ability to import iges or step files and
> in this case there is no characteristic length associated to the
> points, so we have to choose an arbitrary default value. The choice
> is difficult because we have to be able to mesh very small as well
> as very big objects, and also be able to merge step files (no lc)
> with .geo files (imposed lc). And there is also the problem of
> imposed background meshes and of attractor points.
> We are still looking for he best compromise ...
Fair enough.
> We end up with a value for lc that can not be greater than 1/10 of
> the largest dimension of the bounding box (to be able to mesh step
> files).
I am trying to create a tapered mesh from a fine to a coarse region.
If I want one edge to have only one or two elements then the
rectangle must have a length that is 10 times greater than the width.
Is that correct?
> If you want the same kind of behavior in version 2.04 as in version
> 1.65, in _your_ case, you have to modify line 194 in Mesh/
> BackgroundMesh.cpp :
>
> double l3 = CTX.lc / 10.;
>
> becomes
>
> double l3 = CTX.lc / 1.;
>
> and recompile.
Not an option. The code is distributed to others. Could the divisor
be made a parameter that is passed?
--
Daniel Wheeler
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