Node anchoring in tetra mesh optimisation

Altair Forum User
Altair Forum User
Altair Employee
edited October 2020 in Community Q&A

Hi,

 

I have been using the 'tetra mesh optimisation' panel to optimise my meshes. However, with the 'Remesh' option selected and surface nodes anchored during optimisation, few anchored nodes 'disappeared' after the optimisation - they don't belong to any elements at all after the optimisation. I have attached the screenshots taken before and after the optimisation together with the setup I used.

 

Could you please confirm if this is a bug? It existed in HM 12.0 and is still existing in HM 13.0

 

Cheers,

Wensong

<?xml version="1.0" encoding="UTF-8"?>post-32676-0-35457700-1429169127_thumb.j

<?xml version="1.0" encoding="UTF-8"?>post-32676-0-28095900-1429169136_thumb.j

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Answers

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    Hi Wensong,

     

    Can you share the model with us?

     

    Node anchoring was working fine at my end. Let us test with your model.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    I have had this issue before in v11.0 & earlier. It works on a simpIe geometry mesh, but doesnt do a good job on a semi-complex geometry mesh.

    Use Free boundary faces : fixed , that works really well on all meshes.

    If you want a better quality 3D mesh, refine your shell mesh, and then use the tetra remesh with fixed boundary faces.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    Hi Wensong,

     

    Can you share the model with us?

     

    Node anchoring was working fine at my end. Let us test with your model.

     

    Hi Prakash,

     

    The model has been sent to your 'secure file dropbox'. Please check.

     

    Cheers,

    Wensong

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    I have had this issue before in v11.0 & earlier. It works on a simpIe geometry mesh, but doesnt do a good job on a semi-complex geometry mesh.

    Use Free boundary faces : fixed , that works really well on all meshes.

    If you want a better quality 3D mesh, refine your shell mesh, and then use the tetra remesh with fixed boundary faces.

     

    Hi,

     

    Thanks for replying. Glad to know I am not the only one encountered this problem. 

     

    My simulation involves a frequent remeshing and mesh optimisation process which needs to be automated so I am afraid it is not quite possible to manually edit the shell mesh every time.

     

    Regards,

    Wensong

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    Thanks Wensong,

     

    I will check and update you the same.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    Hi,

     

    can you use the settings shown in the image below and check if you see the same issue with the nodes?

    <?xml version="1.0" encoding="UTF-8"?>post-7616-0-09658900-1429266699_thumb.jp

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    Hi,

     

    can you use the settings shown in the image below and check if you see the same issue with the nodes?

     

    Hi Prakash,

     

    'Fix All' under 'Triangles' has always worked fine with node anchoring but 'Remesh' does not. It is the 'Remesh' function that I want to use together with anchored nodes.

     

    Cheers,

    Wensong

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    Hi Wensong,

     

    I tired re-mesh with parameters which I have shared. It worked for me.

     

    with your parameters, you may have to remove the option 'optimize tetras by force' and I think this is causing the problem.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2015

    Hi Wensong,

     

    I tired re-mesh with parameters which I have shared. It worked for me.

     

    with your parameters, you may have to remove the option 'optimize tetras by force' and I think this is causing the problem.

     

    Hi Prakash,

     

    I tried again without using 'optimize tetras by force' but the results still remained the same.

    Can you confirm that 'remesh' was chosen instead of 'fix all' under 'Triangles' (see screen shot attached)?

     

    Would it be possible for you to capture the whole process and send me a video clip so that I can compare it with what I have done?

     

    Sorry about the trouble.

     

    Regards,

    Wensong

    <?xml version="1.0" encoding="UTF-8"?>post-32676-0-41937100-1429600697_thumb.j

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited May 2015

    Hi Prakash,

     

    Any luck?

     

    Regards,

    Wensong

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited May 2015

    Hi Wensong,

     

    I can see at least few nodes are left. I made a video of it and will check with experts what the reason could be. 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited May 2015

    Thanks Prakash,

     

    Please keep me updated.

     

    Regards,

    Wensong

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2016

    Hi there,

     

    I wonder if there is any update on this problem? is it likely to be fixed in next release?

     

    Thanks,

    Wensong

  • Rahul Rajan_21763
    Rahul Rajan_21763 New Altair Community Member
    edited April 2016

    Hi,

    I hope you are referring to the attached issue fixed in 13.110 & latest version is 14.0.

    See attached screenshot from release notes.

     

    Regards

    Rahul R

    <?xml version="1.0" encoding="UTF-8"?>13.110.JPG

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited April 2016

    Hello Zhwang.  The image Shown is not completely emphasizing the issue. But I This the the Nodes that you have shown are Mid nodes, Because of the Change in the order in the Tetra Mesh ,Maybe. I can think at this point these :

     

    1. What is the order of the tetra meshes before and after Optimization ?  It may eat or add nodes from 1st order to 2nd order.

    2. Kindly track the node numbers as Hypermesh adds Fictious ones.

    3. I have observed that to anchor the nodes to the geometry and check it before meshing. As we had these issues in the past.

     

     

    You are welcome to share the model. I would like to learn by understanding the problem.

     

    Cheers

    Girish