Why do metal faces in my simulation all but disappear?

Ted Zeeff
Ted Zeeff Altair Community Member
edited October 2022 in Community Q&A

I have a simulation that consists of a few near-field sources next to a large metal object.  All geometries are PEC.  When I detach the mesh to repair it for simulation, Feko adds the front and back medium options to the triangles. When I run the simulation, all of the metal disappears. What combination of front/back mediums do I need to set to get my PEC objects to show up in the simulation? Where is the documenation for this software?  Am I missing the location where things like this are discussed? All I see in the documents are that these features exist, without explaination.

I have two surface meshes:

    First surface mesh: close to NF sources. Has an enclosed area.  Front medium: Free space, Back Medium: PEC. Face medium: PEC, Solution None

    Second mesh: Open PEC structure connected to first surface mesh. No enclosed area. Front and back medium: Free Space, solution: PO

Any ideas?

 

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Answers

  • Ted Zeeff
    Ted Zeeff Altair Community Member
    edited October 2022

    A quick follow-up to myself.  I made a simple version of my model using exact same settings and everything works with that simple model.  Something is wrong with my geometry or with the software. Reinstalling the software now. 

  • Ted Zeeff
    Ted Zeeff Altair Community Member
    edited October 2022

    Reinstalling did not help. Also, our FAE is not responding. I have to assume that the software is just broken. 

  • Torben Voigt
    Torben Voigt
    Altair Employee
    edited October 2022

    Hi @Ted Zeeff ,

    I'm not aware of any related bug in Feko 2020.1. Could you maybe attach the model (.cfx) here and explain the steps to reproduce the problem?

    Could it be that the faces are just not shown because you only visualize mesh in CADFEKO?

    image

    Note, a "GettingStarted.pdf" as well as the UserGuide can be found in the Feko launcher:

    image

    Best regards,
    Torben

  • Ted Zeeff
    Ted Zeeff Altair Community Member
    edited October 2022

    Thanks, Torben.  I think the issue is that my geometry was corrupt but not showing any signs of corruption until I ran the simulation. I spent many hours improving the geometry, but in the end, it was all wasted because the corruption carried through without any signs of a problem. I think in addition to saving nearly every hour to a new file name, that I will export/import the geometry as well. It's a huge waste of time, but necessary.

     

    As for the documentation, I am looking for practical advice on the features. The documentation simply lists the features. What I have been doing is creating simple models, enabling a feature, and seeing what it does prior to using the feature on the larger model. Is there another way? 

  • Torben Voigt
    Torben Voigt
    Altair Employee
    edited October 2022

    Hi @Ted Zeeff ,

    it sounds like your geometry is extremely large. Does it make sense to simulate it in Feko without simplification, de-featuring etc.? I would imagine that memory requirements and runtime would be extremely large.

    Usually, very complex CAD data is first processed in tools like HyperMesh, so that a mesh suitable for EM simulations can be generated.

    Regarding your question about "practical advice for features", there are already a lot of How To videos on Altair One or on YouTube. Having a single video for every single workflow in Feko is of course not possible.

    Classically, users take part in a training or use our technical support on Altair One.

    Best regards,
    Torben

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