[krzychu111]

Hi,


I'm working on meshing with use of snappyHexMesh, to use it properly I have to provide a stl file with geometry. Unfortunately gmsh doesn't export geometry divided by patches but whole geometry is in single "Created by Gmsh" group. So I want to bypass this issue by exporting patch by patch and by script marge and add group's names.


But I don't know how to export only patch of whole volume. I tried using "gmsh -string "Physical Volume(1) = {27};" or setting visibility to single patch but this doesn't work and each time I got whole geometry.



Does anybody know how to export single patch from volume?

[caja94]

Hello krzychu111,

I am having a similar problem trying to export .stl file from gmsh. Sorry i don't have an answer if you didn't solve this problem, but in case you did, i have a question.
Is it possible to export all patches by their names in .stl files e.g. "fluidInlet" or something like that? Because i only get "Created by Gmsh", the same thing you quoted above.
If you, or anyone else, have an answer, it would be greatly appreciated.

Best regards, Petar

[qwertyus]

Originally Posted by krzychu111

Hi,


I'm working on meshing with use of snappyHexMesh, to use it properly I have to provide a stl file with geometry. Unfortunately gmsh doesn't export geometry divided by patches but whole geometry is in single "Created by Gmsh" group. So I want to bypass this issue by exporting patch by patch and by script marge and add group's names.


But I don't know how to export only patch of whole volume. I tried using "gmsh -string "Physical Volume(1) = {27};" or setting visibility to single patch but this doesn't work and each time I got whole geometry.



Does anybody know how to export single patch from volume?

As of now (v 4.8.3 and a few previous ones), Gmsh allows exporting stl by physical surface, which then can be read in by snappyHexMesh when creating the patches. To do so, go to "File -> Export" and select .stl format. When prompted, select "Per physical surface". Of course, you have to have defined the corresponding surfaces when importing/creating the geometry in Gmsh.

What I'm trying unsuccessfully to do is do that on a .geo script. I was only able to save the stl using default settings (which yield exactly the same result as yours).