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Mesh computation failed

Posted by A. Bhattarai at October 08. 2015

Dear Salome Users,

 

I have a small doubt concerning the mesh computation. I generated a mesh from a geometry using the algorithm: triangle mefisto and wire discretisation. When the generated mesh is computed then a pop-out menu opens displaying "Mesh computation failed" with "invalid input mesh . too few segments: 2" for some faces. The error is attached below.

The strange aspect is when I export the mesh and import again, the message will be gone and mesh computation does not produce any warnings like before.

Could anyone give me some hint if the mesh generation is fine or have to do something else?

Thank you in advance for the support.

Best regards,

A. Bhattarai 

Attachments

Re: Mesh computation failed

Posted by SMESH expert at October 08. 2015

Hello

This error occurs when a boundary of geom face is discretized too coarsely: with only 2 segments. To eliminate this error, set up finer discretization of such a face.

Best regards

Edward

Re: Mesh computation failed

Posted by A. Bhattarai at October 08. 2015

Hi Edward,

Thank you for your quick response. I am not sure how one can do such finer discretisation on particular faces. Do you mean this step has to be done after the mesh is created? 

 I looked into the forum but not able to find information to do so. Could you please add up some lights on this procedure?

Thank you again.

Best regards,

A. Bhattarai 

 

Re: Mesh computation failed

Posted by A. Bhattarai at October 08. 2015

After I repaired the geometry with 

Repair > Shape Process = FixShape + FixFaceSize, about half of the problematic faces are gone. But the problem exists the same for the rest of them. For the fine discretisation on such faces, could you please help me with the procedure?

Thanks again.

A. Bhattarai 

Re: Mesh computation failed

Posted by SMESH expert at October 08. 2015

In a dialog showing errors, select the both lines in Errors table and click [Publish sub-shape]. As a result the problematic faces will appear in the Object Browser under the main shape. Close the dialog, select the mesh, invoke Create Sub-mesh, select the published faces as Geometry, select Wire Discretisation as 1D Algorithm, and create your favorite 1D hypothesis. Change parameters of the hypothesis to get a finer 1D mesh.

Best regards

Edward

Re: Mesh computation failed

Posted by A. Bhattarai at October 08. 2015

Wow, this step is awesome. Many thanks Edward for the hint and considering my little experience on Salome.

 

Best regards,

A. Bhattarai

Re: Mesh computation failed

Posted by A. Bhattarai at October 22. 2015

Hello again,

This time my question is somehow related to the question from the first post. Previously, I encountered the problematic faces of

                   invalid input mesh . too few segments: 2

for which the solution were already explained and could be fixed. However, just to understand, I ran a simple test case with the mesh containing such faces and the simulation went fine with out any convergence problem. 

Since, the simulation ran successfully, at the moment I do not understand, that if those faces might create any influence on the quality and quantity of the results? Also, if the simulation is fine and these faces might not be problematic for the quality and quantity of the results, is it fine to ignore such errors and continue the simulation what I need? Could anyone please guide me about this condition.

Thank you in advance.

Best regards,

A. Bhattarai

Re: Mesh computation failed

Posted by Fynn at May 24. 2017

Hi Edwald,

I am experiencing the same error and would like to visualize the faces on which the algorithm fails. But I am meshing my geometry through a python script, so I don't get the dialog box in which I select the Error and publish the faces as a sub-shape. 

Do you have an idea how I could still get to visualize my faulty faces?

cheers,

Fynn

 

Previously SMESH expert wrote:

In a dialog showing errors, select the both lines in Errors table and click [Publish sub-shape]. As a result the problematic faces will appear in the Object Browser under the main shape. Close the dialog, select the mesh, invoke Create Sub-mesh, select the published faces as Geometry, select Wire Discretisation as 1D Algorithm, and create your favorite 1D hypothesis. Change parameters of the hypothesis to get a finer 1D mesh.

Best regards

Edward

 

Re: Mesh computation failed

Posted by Saint Michael at May 24. 2017

Hi Fynn

To get the dialog box with meshing errors, just invoke Compute of your mesh in GUI. As meshing parameter do no change, nothing will be re-computed and you will see the same errors in the dialog.

St.Michael

Re: Mesh computation failed

Posted by Sita Drost at September 26. 2018

Hi everyone,

Thanks a lot for these comments (and this forum in general)! I remember getting a meshing error earlier, and using Publish Sub-shape to get it fixed, but now this Publish Sub-shape button is greyed out and it will only let me use Show Sub-shape. Am I doing something wrong?

Some details: I'm using Salome 8.4.0 on Ubuntu 18.04, and at the moment I'm trying to mesh several faces on a solid geometry.

Thanks in advance for any help,

Sita

Re: Mesh computation failed

Posted by Saint Michael at September 29. 2018

Hi Sita

Publish Sub-Shape is greyed out when a sub-shape is already published in the Object Browser.

St.Michael

Re: Mesh computation failed

Posted by Sita Drost at October 04. 2018

Hi St. Michael,

Thanks, I'll see if I can find it in the Object Browser somewhere.

Sita

 

Previously Saint Michael wrote:

Hi Sita

Publish Sub-Shape is greyed out when a sub-shape is already published in the Object Browser.

St.Michael

 

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