There are always some black lines between elements ?

LIMING LI_21655
LIMING LI_21655 Altair Community Member
edited November 2020 in Community Q&A

image

When I try to repair the elements at the boundary of the model, there are always some black lines appearing. Is this normal? How should I solve this problem?

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Best Answer

  • Viraj Kulkarni_21218
    Viraj Kulkarni_21218
    Altair Employee
    edited November 2020 Answer ✓

    Hi Liming,

    Here are few things you can check if those elements really have some problems or is it a graphics issue.

    Firstly are these 2d-shell elements or is it a tet mesh?

    1)You can use this Tools-->edges panel to check if there is a connectivity issue for the elements.

    image

    Enter tolerance for search according to your model dimensions. You can click view edges. If you see edges in between where elements should be connected there is an issue. (It shows edges-which are shared by only 1 element) You can click preview equivalence-where it can equivalence nodes within tolerance.

    2) Also check if there are any duplicate elements by Tools-->check elems panel

    image

    Try masking one or two elements to inspect the area as well.

    You can use all these options to find/fix your connectivity issues. If all is good it might be just graphics issue.

     

Answers

  • Viraj Kulkarni_21218
    Viraj Kulkarni_21218
    Altair Employee
    edited November 2020 Answer ✓

    Hi Liming,

    Here are few things you can check if those elements really have some problems or is it a graphics issue.

    Firstly are these 2d-shell elements or is it a tet mesh?

    1)You can use this Tools-->edges panel to check if there is a connectivity issue for the elements.

    image

    Enter tolerance for search according to your model dimensions. You can click view edges. If you see edges in between where elements should be connected there is an issue. (It shows edges-which are shared by only 1 element) You can click preview equivalence-where it can equivalence nodes within tolerance.

    2) Also check if there are any duplicate elements by Tools-->check elems panel

    image

    Try masking one or two elements to inspect the area as well.

    You can use all these options to find/fix your connectivity issues. If all is good it might be just graphics issue.

     

  • LIMING LI_21655
    LIMING LI_21655 Altair Community Member
    edited November 2020
    Viraj Kulkarni_21218 said:

    Hi Liming,

    Here are few things you can check if those elements really have some problems or is it a graphics issue.

    Firstly are these 2d-shell elements or is it a tet mesh?

    1)You can use this Tools-->edges panel to check if there is a connectivity issue for the elements.

    image

    Enter tolerance for search according to your model dimensions. You can click view edges. If you see edges in between where elements should be connected there is an issue. (It shows edges-which are shared by only 1 element) You can click preview equivalence-where it can equivalence nodes within tolerance.

    2) Also check if there are any duplicate elements by Tools-->check elems panel

    image

    Try masking one or two elements to inspect the area as well.

    You can use all these options to find/fix your connectivity issues. If all is good it might be just graphics issue.

     

    Hi Viraj,

    Thanks for your help.

    Often the unit near the black line is faulty, but the black line is still displayed after the fix is completed.  I have also used the options you introduced to find the connectivity and all is good. It seems to be just graphics issue.

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