[Gmsh] How to separate faces in an *.STL file

[Mark van Doesburg]

Hello Alex,

I am using BRL-CAD to generate input for gmsh as well. What I initially
did was to use g-iges to generate a faceted brep model, for example:

	g-iges -o region.iges -f brl.g region.r


For each region I generated a seperate IGES file. If you merge the iges
files using the Merge command in the .geo file you can add physical
regions and surfaces.

When using the IGES format, each triangle will be a seperate geometrical
surface.

regards,

Mark van Doesburg


Alexandre Pereira <iskandhar2000 at gmail.com> wrote:

	Hi Forum

	I want to use GMSH to mesh *.stl files that have been built
	elsewhere ( In BRL CAD to be more exact ) which will be used as
	models for FEA analysis in Code Aster.

	I want to export them in *.med format containing the
	mesh info as well as some topological info about physical
	lines/surfaces/volumes.

	In GMSH, I can import the *.stl, define a volume using the *.stl
	boundary, mesh/refine the boundary, and mesh/refine the created
	volume, what i cannot ( do not know how to ...) do is to separate
	the boundary of my *stl in primitive faces to give the a physical
	meaning ( they will be used on Boundary condition addressing in
	ASTER ), can this be done in GMSH, or sould I build my geometry
	in GMSH prior to do all this...?


	My maisn issue is that BRL CAD contains some 3D primitives that do
	not exist in GMSH, like elliptical/hyperbolic cones generalyzed
	ellipsoids, etc, and I use the generated surfaces in my *.stl
	as boundaries in some of my models....


	Can someone please help...?


	Best regards


	Alex