Re-use meshes

[jomey]

Is it possible to save the calculated meshes and re-use them on later runs?

I found this config option in the wiki WRITE_FOAM_FILES, but then am unsure how to tell WindNinja on a second run how to use these.

My use case has WindNinja running every morning via cron job and catching up with simulation from the previous day. My simulation domains are quite large (related question here #569) and saving the meshes on an unchanged topography seems an easy one to not to redo every day.

I also found #176 which seems exactly for what I am looking for, but could not find the PR where it went in.

[nwagenbrenner]

Hi Joachim, You should be able to set the existing_case_directory option in the CLI to re-use an OpenFOAM case (and mesh). This is not a commonly used/tested feature, so let me know how it goes. I'm short on time right now, but can help if you run into issues. Hopefully this helps. Thanks, Natalie

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On Fri, Dec 12, 2025 at 8:50 AM Joachim Meyer ***@***.***> wrote: Is it possible to save the calculated meshes and re-use them on later runs? I found this config option in the wiki WRITE_FOAM_FILES, but then am unsure how to tell WindNinja on a second run how to use these. My use case has WindNinja running every morning via cron job and catching up with simulation from the previous day. My simulation domains are quite large (related question here #569 <#569>) and saving the meshes on an unchanged topography seems an easy one to not to redo every day. I also found #176 <#176> which seems exactly for what I am looking for, but could not find the PR where it went in. — Reply to this email directly, view it on GitHub <#674>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AA4GQDL5I3RZB7TTNDLG74D4BLP4XAVCNFSM6AAAAACO3VPUACVHI2DSMVQWIX3LMV43ERDJONRXK43TNFXW4OZZGI2DCNRUHA> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[jomey]

Thank you, Natalie.

To clarify, setting the WRITE_FOAM_FILES=1 should be enough to use the existing_case_directory parameter? Or should that be =2?

Cheers,
Joe

[nwagenbrenner]

Hi Joe, We actually removed the WRITE_FOAM_FILES environment variable a while back. It was mainly used for debugging purposes as it allowed you to write various stages of an OpenFOAM case without actually executing it. We'll have to update our wiki to remove that configuratoin option. I think what you want is just the existing_case_directory option in the CLI (it doesn't rely on any other environment variables). Please take a look at this and let me know what you think. This option should let you re-use a case for running under different input conditions without rebuilding the mesh each time. Like I said, the option is not frequently used, so let me know if you encounter issues with it and we can take a look. Hopefully it will just work for you though. Thanks, Natalie

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On Fri, Dec 12, 2025 at 11:15 AM Joachim Meyer ***@***.***> wrote: Thank you, Natalie. To clarify, setting the WRITE_FOAM_FILES=1 should be enough to use the existing_case_directory parameter? Or should that be =2? Cheers, Joe — Reply to this email directly, view it on GitHub <#674 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AA4GQDL2DMEPW3CFXQAR5234BMA3BAVCNFSM6AAAAACO3VPUACVHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTKMRUGI4TEMI> . You are receiving this because you commented.Message ID: ***@***.***>