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Wien3 October 20, 2014 09:14

Check overlapping faces: This seems to be a bug in the grid
Good afternoon,
Iīm new using this web and also about using Blender and engrids. In order to start learning how to use it I have started making the tutorial called "Unstructured Grids for OpenFOAM With Blender and enGrid 1.2", which is in the own engrid Homepage.

I followed all Blender steps without any Problem, including checking if itīs watertight and removing double Vertices (I hope I did it well). The Problem is that when I export this model to enGrid and click in the Option "Check overlapping faces" the message which appears is:

"This seems to be a bug in the grid. File: facefinder.cpp. Line:39". As the beginning I didnīt take care of that, so I tried to follow the next steps, assigning boundaries, creating the volume and so on (These didnīt cause Problems).
Of course when I tried to make a mesh it doesnīt work. Actually I donīt know if itīs a Problem of de blender file or just because Iīm doing something wrong in enGrid.

I attach both elements, hoping someone could see my mistake.

I would really really appreciate any kind of help.
Thank you

Wien3 October 20, 2014 10:30

These are the files I told about:

Attachment 34482

Wien3 October 22, 2014 07:28

Ok, I achieved to solve the problem. It was due to I did not proper triangle the different faces.
Concerning the mentioned tutorial, I did it succesfully until 'Extruding prismatic layer'. When I create it (selecting icosphere and removing points), the programm crash and appears the following message:

p, li { white-space: pre-wrap; } Netgen stopped with the following error:
Illegal position in Geomsearch

I don have any idea about how to continue. Just I could say is the only step which I did not the same than the tutorial is when he create the rule mesh. At least to me it doesn't appear the "adding set" (I guess it is because of the version 1.4) so I surfed the net and I found these should be the commands to introduce in that box:

Back <AND> Inlet <OR>
Bottom <AND> Inlet <OR>
Front <AND> Inlet <OR>
Inlet <AND> Top <OR>
Back <AND> Outlet <OR>
Bottom <AND> Outlet <OR>
Front <AND> Outlet <OR>
Outlet <AND> Top <OR>
Back <AND> Bottom <OR>
Bottom <AND> Front <OR>
Front <AND> Top <OR>
Back <AND> Top = 0.1;


I would really appreciate any kind of help, just for not going crazy :confused::confused:

I attached the engrid and blender files.

Thank you

Wien3 October 22, 2014 07:40

And enGrids...

BlnPhoenix December 2, 2014 09:25

Hi Wien3,

did u manage to create the prismatic boundary layer in your geometry? I'm having difficulties to do so. It says that i have 'overlapping faces' which i dont know what to do about it.

Kind regards!

KateEisenhower May 4, 2015 05:32


I suggest you go back to blender and try to repair your geometry. Be sure to check your geometry (page 7 on Once you have imported a valid geometry in enGrid, you can improve your surface mesh before you start building your boundary layer.

Best regards,


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