[Gmsh] How to obtain small characteristic length in specific area of geometry?

[Mikhail Artemiev]

Hi, John.
When I load your .geo file to my Gmsh 2.5.0 for Windows, it sais that

Error   : 'John.geo', line 628 : Unknown option 'DistMax' in field 1 of type 
'BoundaryLayer'
Error   : 'John.geo', line 629 : Unknown option 'DistMin' in field 1 of type 
'BoundaryLayer'
Error   : 'John.geo', line 630 : Unknown option 'LcMax' in field 1 of type 
'BoundaryLayer'
Error   : 'John.geo', line 631 : Unknown option 'LcMin' in field 1 of type 
'BoundaryLayer'
Error   : 'John.geo', line 632 : Unknown option 'LcMax' in field 1 of type 
'BoundaryLayer'
Error   : 'John.geo', line 633 : Unknown option 'LcMax' in field 1 of type 
'BoundaryLayer'
Error   : 'John.geo', line 634 : Unknown option 'Sigmoid' in field 1 of type 
'BoundaryLayer'
Error   : 'John.geo', line 635 : Unknown option 'StopAtDistMax' in field 1 
of type 'BoundaryLayer'

And I really didn't find these options in Gmsh documentation for 
BoundaryLayer type of field (only for Threshold).
Anyway I can advise you to reduce your tolerance variable on 
"Options->Geometry->General".

Mikhail


>Hi,

>I've been successfully using gmsh for some time, but now I would like to
>specify a much denser mesh around one of the structures in my geometry. I
>have tried using the boundary layer, box, and attractor fields to control
>the characteristic length but they seem to be having no effect on the
>generated mesh.

>Attached is my geometry, I would like to have a characteristic length in 
>the
>region of 1e-8 around the cantilever (or 'diving board') feature in the
>centre of the geometry. Is this characteristic length too small I wonder?
>How should I achieve the desired effect? The attached file has the boundary
>layer that I would like to use, but it has no effect on the mesh density.

>Thank You in advance for any pointers you can share with me.

>Regards,
>John Parkin