How to mesh Solid objects in step-54?

[HIMAL MAGAR]

Hello,

I am trying to mesh an oxygen gas cylinder(which is part of our project in our University) using step-54. For simplicity, I have generated a coarse mesh(cuboid) using step-1 and prepared .IGS file of a cuboid of same dimension. But , I have encountered following error while running it:

PS: After this error, I have done/tried following things:

1. changed the scale among 1e-3, 1 and 1e+3

2. increased the tolerance up to 100.

...but the error is still present.

Thanks,

Himal.

[Marc Fehling]

Hi Himal,

the vertices of your coarse mesh must be located on the geometry provided by the IGES file.

It is hard to tell from that amount of information where exactly your error comes from. I advise you to draw a sketch of both your IGES cylinder and your coarse mesh. Usually you should find out this way what the error message is about.

On a different note: Creating a cylinder out of a cuboid is general not a good idea, as your cells near the corner vertices get distorted. I would rather advise you to choose a coarse cylinder from our GridGenerator namespace instead.

Marc

[HIMAL MAGAR]

Thank you for your response. Actually I was trying to learn the code by testing simple case(i.e a cuboid). Here is another problem:

I made a mesh surf.vtk in gmsh from a step file. When exporting from gmsh, the vtk version in the file was 2.0. So, I changed it to 3.0 and still I have got the following error:

The surf.vtk file contains following mesh:

Thanks!

Himal.

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[Marc Fehling]

Hi Himal,

please double check if you are loading the correct vtk file. Because that line is clearly present in the screenshot you posted.

In step-49 we are using the msh file format when working with Gmsh. Maybe you have more success with this format?

Marc

[HIMAL MAGAR]

Dear Sir,

As you suggested, I worked on the .msh format. And it WORKED!!. Thank you so much.

 A quick question, while working on 3d meshes, I frequently encounter the error " the point(...) is not on the manifold". I know what the error is about and I have confirmed the vertices of the coarse mesh are on the manifold. However, the error pertains. Are there any other sources that this error might have happened?

Thanks again.

Himal.

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[Marc Fehling]

Hi Himal,

I'm glad it works now with the msh format.

You can look at the implementation of the "the point (...) is not on the manifold" check and convince yourself that if you encounter the error, then it is because the point is not on the manifold within the given tolerance. How did you confirm that the vertices are on the mesh? I would not try to silence the error by increasing the tolerance. Usually it indicates that something is wrong with your setup, and you should investigate the cause of the error.

Marc

[HIMAL MAGAR]

Hi Marc

Thank you for your reply. I had confirmed that the vertices were on the manifold by visualizing the coarse mesh( in .vtk format) and .iges file in gmsh together.

 Thanks.

Himal.

To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/37973012-83e9-483f-9b9e-e9ba80ff9b25n%40googlegroups.com.