[Gmsh] meshing differences between version 1.65.0 and 2.0.4

[Daniel Wheeler]

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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