[Reptider]

Hello!
I create physical surfaces for using them in OpenFOAM later in .geo thanks to:

Merge "fisrt.stl";
Surface Loop(1) = {1};  // first surface*
Physical Surface("firstWall") = {1};

Merge "second.stl";
Surface Loop(2) = {2};  // second surface*
Physical Surface("secondWall") = {2};

Volume(1) = {1,2};
Physical Volume("Volume") = {1};

I can create a stl file using Export -> ASCII + per physical surfaces and receive nessecary results in stl file like:

solid firstWall
... 
endsolid firstWall
solid secondWall
...
endsolid secondWall

However, when I use in the terminal this command: "gmsh -2 name.geo -o name.stl:, I get a single solid:

solid Created by Gmsh
...
endsolid Created by Gmsh

How can I do this operation using only the terminal?
Thanks!

[saladbowl]

I figured a way to do this by changing some default options in gmsh. I am using version 4.8.1. Open the GUI, then

Help --> Current Options and Workspace

Then search for the option Mesh.StlOneSolidPerSurface and set it to 2;

Mesh.StlOneSolidPerSurface = 2;

Click Update (lower right corner)

Before closing gmsh, go to Menu "Tools", select "Options", select "Advanced Tab" and check the option "Save options on exit".

Now when meshing and exporting from the command line you should get the desired behaviour.