How to make a mesh so that it does not have negative volume?

Vladimir001Vladimir001 Member
edited August 21 in Preprocessing

I make a project in a workbench, geometry in the Design modeler with maximum accuracy, exported the geometry to icem cfd, made a mesh using blocks, after exporting to CFX and setting the boundary conditions, it gave an error that there is an orthogonal volume, how to fix if the inner side is approaching the outer and I can't fix it, I tried the automatic method, it doesn't work, I also found a video on how to fix it, -failure {link to video (} please help, I will attach all screenshots and the icem project to the question.

blue is the inner side

Here you can see that the inner side crosses the outer, the project is available at the link, could not download it, more than 50 MB:

Best Answer


  • RobRob UKForum Coordinator

    How thick is the domain? It's rare for faceting to cause surfaces to touch unless the gaps are of the same order as the CAD tolerancing.

  • Vladimir001Vladimir001 Member
    edited August 23

    The largest distance is 75 microns, the thickness of the 30 elements, design modeler,also did geometry in parasolid-xt format but there is the same as on the first geometry, also merge these 4 sites

  • RobRob UKForum Coordinator

    Scale up so gaps are 7.5mm also increase the CAD faceting (SpaceClaim File>Options>CAD/geometry to 10). CAD tools tend to be accurate to 0.1 or 0.01mm so 75microns is going to cause problems. In Fluent you can scale the mesh back to the desired size.

  • Ok, thanks, I did as you said, but the blocks that I oriented overlap. is this a possible problem?

  • RobRob UKForum Coordinator

    If those are the mesh blocks then it could be. Because of the domain size relative to the thin section you may struggle due to tolerance issues.

  • Thank you, but if the tolerance and scale of the model do not affect the result, then what other ways can there be to solve the problem?

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