Delete free nodes

oggy
oggy Altair Community Member
edited October 2020 in Community Q&A

Helloevrybody !!

 

I found a free nodes in my geometry & i want to run a simulation with radioss. any help pllz ?

 

tHNAKS

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Answers

  • Rahul_P1
    Rahul_P1
    Altair Employee
    edited January 2015

    Oggy ,

     

    Can you put up an image and explain what you mean by free nodes?

     

    Do you mean free 1D element nodes?

     

    To rectify free 1D elements, please follow the procedure below:

    Go to 1D > Rigids > Update > Connectivity > select the free rigid element > make sure dependent node selector is active > deselect the node > click on Update 

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited December 2015

    Hi,

      How can we see the Free nodes of a Hypermesh model.

  • Rahul_P1
    Rahul_P1
    Altair Employee
    edited January 2016

    we talk about free nodes in the context of 1D usually and the procedure to see them and rectify them are as in the above post.

     

    If there are nodes in your model that are not associated with anything, you can hide your complete models, create temp nodes by adding all displayed nodes, use fit or f key and visualise them in that way

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2017

    Yes ... But it doesn't answer the question. As you said, these free non-structural nodes are generally hidden and can be identified by creating temp nodes selecting them by having the model completely toggled off. Some of them are created as automatic references such as vectors or coordinate systems or some miscellaneous keywords coming from other solvers such as LS-DYNA. Others are created when some part references are lost or some uncontrolled element deletion takes place involving fixed sets.

     

    When handling complex models and going through multiple project steps handling, these free nodes tend to accumulate and can mess up further meshing or setup operations pretty much if stringent numbering control is not done, and are also pretty annoying since these, although hidden, are still selectable when performing, let's say, a Ruled operation, prompting for mistakes that could not be detected at first glance. Or they are automatically considered for display fitting operations, normally making your view angle distorted or pretty zoomed out. Some external solvers might even crash due to detecting them as massless or pure rigid body motion nodes.

     

    So, the real question here was .... How to delete these nodes? I haven't found any practical way to do so but to identify their number and erase them from a manually exported deck. Which is definitely not practical.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited June 2017

    Well ... Seems like effectively creating the temp nodes and them clearing them all again would seem to work. But confirmation pending.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited October 2017

    Alex,

     

    It has been a while since you asked that question. I don't know if you still need help. If you do, please check Analysis -> Preserve nodes see if there are any preserve nodes in your model. HM would automatically delete those once you transfer any preserve nodes to normal nodes.

  • Altair Forum User
    Altair Forum User
    Altair Employee
    edited December 2017

    Hi Alex and Frehab, 

     

    You both posted quite 'a while ago' but, thanks to your posts, I came up with a workaround of sorts, which isn't very straightforward but helps me as long as there are not tons of rigids to clean. So I would recommend to use it as soon as you start making the first group of rigids in your model.

    To put it simple: 

     

    INITIAL ASSUMPTION: you have FREE 1D NODES in A NUMBER OF RIGIDS

     

    PROCEDURE

    0.SAVE A COPY OF YOUR FILE BEFORE DOING THIS. CAUTION IS ALWAYS THE BEST WAY IN THIS KIND OF THINGS.

    1.Visualize with F10 your free 1d nodes-->save them in the user mark (save found)

    2.create a dummy component. In this component create a rigid retrieving ALL THE NODES SAVED IN 1. This will automatically make HM see them as no more free nodes.

    3.Now go to 2D/3D-->Detach. Detach your rigids (the ones you have created and you WANT TO KEEP) from their components. This will make all the 'correct' nodes of the rigids free nodes.

    4.F10-->recheck 1D free nodes-->you should be able to visualize your correct nodes as free now. Save them in the user mark 

    5.Go to Analysis-->Preserve Nodes-->Retrieve your correct nodes from the user mark (stored in 4) ad click make preserve.

    6.Go to Analysis-->entity sets-->create a set-grid of nodes with these nodes (the ones saved in 4 retrieve them from the user mark as they still should be there). Now you have saved and you can retrieve all the nodes you wish to  keep.

    7.Delete the rigid created in point 2. This will delete all the free nodes (the ones you wished to DELETE IN THE BEGINNING) as well.

    8. Delete your original rigids too. Switch to your actual rigid component and make new rigids. All the dependent nodes are placed in the entity set created at point 6. So you just have to recreate them.

     

    I know it can be bothersome but it should get the job done by click and not by looking for all the nodes in the solver exported file.

     

    Let me know if this helps. And more importantly, let me know if you managed to find a better workaround.