[Gmsh] holes and layers

[Christophe Geuzaine]

Jin Chen wrote:
> 
> On Tue, 17 Jun 2003, Christophe Geuzaine wrote:
> 
> 
>>Jin Chen wrote:
>>
>>>Hi,
>>>
>>>I am starting to learn Gmsh. Can anyone explain to me what they are and
>>>how to use them ?
>>>
>>
>>- "Holes" stands for "holes in a surface or a volume". See e.g.
>>tutorial/t4.geo for the definition of a surface with a hole in it, or
>>tutorial/t5.geo for the definition of a volume with holes (cavities).
>>
>>- "Layers" is only used in conjunction with the "Extrude" command, and
>>specifies how many layers of elements you want to generate during the
>>extrusion. See e.g. tutorial/t3.geo.
> 
> Can we see these layers after meshing?

Yes. If you only display the volume elements and choose a different
volume number for each layer (cf. 9000, 9001, 9002 and 9003 in t3.geo),
each layer will have its own color.

> 
> How to decide the number of layers and the number of subdivision? From the example,
> there are either 3 or 4 layers.

It's up to you. If you don't need multiple volume numbers along the
extrusion, just change the number of subdivisions. This is usually what
I do.

> 
> Also how to assign the volume numbers to them? What's does each layer's
> height means?

See http://geuz.org/gmsh/doc/texinfo/gmsh_5.html#SEC36

> 
> Can you give me an example to extrude a point or line with layers?
> 

Just replace "Surface" with "Line" or "Point".

Christophe

-- 
Christophe A. Geuzaine
Applied and Computational Mathematics, Caltech
geuzaine at acm.caltech.edu - http://geuz.org