# Create sub-mesh with GSH3d/BLSURF

Hello everyone

I have a problem in generating sub-mesh using BLsurf and GSH3d in order to refine only a part of my domain.

What parameters I Have to set for making it works (even for a simple geometry). I tried to perform it to a cube partitioned (a simple sub-cube inside) but it doesn't works for now...

netgen as 3D algorithm and Mefisto for 2D with different hypothesis to max size for regular 1D (factor 3 of difference) works pretty well. I get my cube refined.

GSH3d is supposed to be more powerful, so I think that I made some mistakes in parametrising it

Thanks for your help

Hello Cyril

You are right, in V6.5.0 BLSURF is hard to be used with sub-meshes. To be precise:

IMpossible usage:

mesh - BLSURF

sub-mesh - BLSURF

Possible usage:

mesh - Netgen 2D

sub-mesh - BLSURF

In V6.6.0, coming soon, BLSURF will be fully-functional.

As about GHS3D, it should be OK.

Best regards

Edward

Thank you very much smesh expert for your help.

Now it works well even with a more complex geometry with your configuration, nevertheless I have several questions :

Is it possible to automatically refine mesh near detailed locations with BLsurf as well as netgen do ?

What is the best parametrisation when using Hexotic to perform the same task of refined submesh ?

It seems that the hexotic algorithm ignore any of the 2D/1D hypothesis such as BLSURF physical size or regular 1D.

Cyril

Hello Cyril

Is it possible to automatically refine mesh near detailed locations with BLsurf as well as netgen do ?

Yes, it is. Among fields of BLSURF_Parameters hypothesis, there are parameters of "Geometric Mesh" (Angle Mesh S, etc) which define allowed deviation of mesh elements from geometry. Click Help in Hypothesis Construction dialog for more description of Geometric Mesh parameters.

What is the best parametrisation when using Hexotic to perform the same task of refined submesh ?

It seems that the hexotic algorithm ignore any of the 2D/1D hypothesis such as BLSURF physical size or regular 1D.

AFAIK, Hexotic mesher uses the input 2D mesh just as definition of geometrical domain to be meshed. On curved refined surfaces it generates finer 3D mesh, but on planar refined surfaces it generates coarse mesh.

Best regards

Edward

Thanks again Edward

As far as I tested the "geometric Mesh" parameters, I didn't succeed to refine near curvatures. I observed that :

- Angle mesh S/C had no influences

- Modify max/min geometric size only refine in a homogeneous manner without getting smooth near curvatures

Is this right ?