TELEMAC-MASCARET Forum: Insert submesh at boundary location (2/2)

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TOPIC: Insert submesh at boundary location

Insert submesh at boundary location 9 years 4 weeks ago #18707

Serrer
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Posts: 720
Thank you received: 304

Hi Guys,

It turns out that this IS a precision problem but not perhaps in the way you might expect.

Explanation:
When Blue Kenue searches for common nodes between the two meshes it uses a proximity tolerance value equal to 1% of the minimum edge length. In this case it turns out to be 0.015662

In Christophes example above the distance between the two nodes is 0.031145 hence we're missing this common node.

I'm guessing that you have saved the submesh to a selafin file at some point and then extracted it again. Whereas the GreaterMesh was not. The Selafin file is single precision so
the node coordinate Y value 4093807.469 is rounded to 4093807.5
And viola, the error.

I suppose the solution is for NRC to implement support for double precision selafin files. In the meantime a work-around is to keep all data in native EnSim t3s/t3m file formats until the end.

Cheers... Martin

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Insert submesh at boundary location 9 years 4 weeks ago #18712

cyamin OFFLINE openTELEMAC Guru Posts: 997 Thank you received: 234	Hello Martin, Your explanation makes sense once the error is introduced. However I did not save the submesh (nor the greater mesh) in selafin format at any point and I have noticed that the precision error is introduced right after the mesh generation and only at the boundary nodes. Interior nodes keep their precision. Regards, Costas
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Insert submesh at boundary location 9 years 3 weeks ago #18713

Serrer OFFLINE Moderator Posts: 720 Thank you received: 304	Hi Costas, Arrrrgggghhhhhh! I think I know what's going on. Are you using Blue Kenue V3.3.4? Lets take this offline for a bit. Send me an email. Martin
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Insert submesh at boundary location 8 years 10 months ago #19227

Santoro OFFLINE Fresh Boarder Posts: 5	Hello Costas, Martin and Christophe, Thanks a lot for this post!! I tried in the past to do this and I had the same problem. The shift to local coordinates also worked for me. Regards, Pablo
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