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Old   December 6, 2021, 19:11
Default Surface Intersects Self
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Hello everyone,

I am trying to do a simulation of a racing car as you can see under Geometry > Parts. After solving some problems with the mesh, I was able to do the mesh operation with a base size of 0.3m. Whenever I try to refine even more the base size, I get the error ' Surface Intersects Self'. I am using the meshers seen in the picture.

Additionally, the mesh that I am getting has some issues as you can see in the picture.

I was wondering if anyone would have any suggestions of what the cause of this issue would be.

Thank you.
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File Type: jpg Meshers.JPG (46.6 KB, 90 views)
File Type: jpg Error.jpg (34.6 KB, 78 views)
File Type: jpg Front Wing Mesh.JPG (99.7 KB, 106 views)
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Old   December 7, 2021, 06:39
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Hi Jselin.

I suggest you to import geometries in 3D CAD module and use imprint operation inside the 3D CAD. That can eliminate self intersection errors.
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Old   December 8, 2021, 06:55
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Hi Jselin,
if the intersection error ocurs and the meshing process is aborted, you should right click on your geometry (in your case I think "SUBTRACT") and select "Repair Surface". In the next dialogue you can select "Latest Surface" under Geometry Description. Now you can identify your problem regions and maybe you see better whats to do.
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Old   January 1, 2022, 10:52
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Hi everyone,

Thank you very much for your answers.

The problem was indeed with the CAD geometry, apparently although the surfaces are closed, they are 'non-connex', so at the moment of importing them to STAR CCM+, it gives these errors.

As I cannot improve the quality of the CAD, I solved the issues by firstly doing imprints in the problematic surfaces, enabling the option ''reimprint existing contacts'', and then doing surface wrappers in each surface with the options ''pre-part meshing'', ''perform curvature refinement'' and ''perform proximity refinement'' enabled. This solved the issues regarding the mesh quality. The Repair Surface tool helped me a lot to identify the areas where there was poor meshing.

I hope this helps to anyone with similar problems.

Thank you again,

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Old   September 6, 2023, 13:51
Default Change the Tessellation Settings on subtracted parts
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Looks like an old post... but ran into the same issues.

I imported my geometry as using a .stp file. I fixed this issue by changing the tessellation of the geometry to "very fine." You can change this settings under the "Tessellation Options" when right clicking on the geometry part. Also be sure to select "All CAD Edges" under the "Mark feature Edges" option.

If you used a subtraction operation with your part selected, make sure you change ALL your subtraction parts to these tessellation settings as well.

You can always check your mesh by right clicking on your domain (Fairfield), go to "Surface Repair," and then change the setting from "root" to "latest surface." Then in the bottom right of the screen, press "execute all." If you see orange or red cells, you will get the intersection error. But you shouldn't get those errors if you changed the tessellation settings.
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Old   September 7, 2023, 01:08
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Imprint. Prior to any Part Operation (Subtract, Unite etc) - do Imprint.
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