******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Hello everyone, to gain experience with NekMesh I first decided to generate a simple 3D boundary layer mesh after working my way through the very helpful tutorials. I started with creating a square duct in Gmsh, exporting the geometry as a STEP file (as recommended in the user guide) and finally feeding it to the mesh configuration file (MCF) and it worked very well. However, since in my case it is necessary to pass the parameter “BndLayerSurfaces” within the MCF, I tried to figure out where this information is stored inside the STEP file. Of course, to first set up the MCF I used the surface information written in the GEO file provided by Gmsh, but I wondered what would happen if I didn’t have a GEO but only a STEP file, e.g. of a more complex geometry created with a more sophisticated CAD tool? How would I know the necessary “BndLayerSurfaces” IDs in such a case? Thanks in advance and all the best, Alex