STEP file meshing

Heather777Heather777
Two questions related to importing and meshing step files.

1.) If meshing fails and log (in command window) denotes problem with a particular surface (say 25) is
there a way to interrogate from GUI what surface MECWAY/netgen is referring to in the STEP rendering?

2.) When meshing fails "spectularly" and the command window disappears is the
log file saved for review?

thanks

Comments

  • SebastianmaklarySebastianmaklary
    edited December 2025
    Hi Heather
    1) The only way I have found to find the particular surface is to download netgen and open the part and in the geometry tab select "edit face mesh size" and then click up until the face number is selected as it is then highlighted. This is however very difficult if the face is very small or if it is not visible from the outside of the part, which can often be the case for failing meshes. I've opened a ticket in Mecways Github, asking for a tool to find faces on the geometry based on face ID. You can see it here on this link and make it known that you also wish for that feature to be implemented.

    2) Not that I know of but when meshing fails, I always sit ready with windows snipping tool to make a "screenshot" of the command window so I can see which faces are failing at being meshed.
  • VictorVictor
    There's a hack you can do. Edit the liml file and delete the <triangle> elements with the surfaceid that you're interested in from the <preview> element. Then open it again and that surface doesn't appear.

    I'm not sure if these ID numbers are the same as reported by Netgen though. They might be off by 1.



  • SebastianmaklarySebastianmaklary
    I just tested this with a simple but asymmetric box shape, which has 6 faces. The .liml file has triangle surfaceid from 2 to 7 and I can confirm that triangleid 2 is the face number 1 in netgen mesher, so the .liml file is off by 1 compared to Netgen.

    The STEP file has 6 FACE_BOUND entities, 6 PLANE entities and 6 ADVANCED_FACE entities. The ADVANCED_FACE entities are referenced in a CLOSED_SHELL entity if it is a closed solid box or a closed surface model and referenced in an OPEN_SHELL entity if it is an open surface model.
    By editing the STEP file and removing the referenced faces in the OPEN_SHELL entity, I have confirmed that the first defined "ADVANCED_FACE" entity corresponds to the surface that Netgen names face index 1 and which the .liml file names surfaceid=2.
    When the reference to the first face removed from the OPEN_SHELL entity, both Netgen and Mecway just assigns the next one as the first face.

    I honestly thought that the STEP file would have something that said "FACE ID 1" but apparently it just comes from the order that the faces are defined in the STEP file.

    It is still difficult to identify where the problematic face is, if it is not something that you would easily notice being missing but this also allows looking at the coordinates x0,y0,z0,x1,y1,z1,x2,y2,z2 in the <triangle surfaceid="2" lines in the .liml file to try to identify where the face is in the model.
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