Hi Peter, Interesting. This seems to be a problem with the generation of the geometry, not the meshing.
Attached is the .brep file of the buggy surface (debugSurface.brep): - the OpenCASCADE representation is wrong (see attached picture of the OpenCASCADE-produced STL triangulation), which seems to indicate that the parametric representation is wrong - the surface also leads to an incorrect mesh with Gmsh 4.4.1 I would suggest to send the "debugSurface.brep" file to the OpenCASCADE developers for further analysis? Christophe
debugSurface.brep
Description: Binary data
> On 11 Mar 2020, at 12:40, Peter Johnston <[email protected]> wrote: > > Hello, > > I have just observed some strange behaviour with my python script running > gmsh. Attached is a cut down version of a larger script that used to work > under gmsh 4.4.1. This script creates a 3D volume using OCC and contains > multiple surfaces. When I mesh the surface (ie use the 2D meshing button on > the gui) surface number three gives some strange results; so strange that I > cannot create a volume mesh. I have also attached a picture of the mesh on > surface 3, indicating the places where the mesh is misbehaving. I am > currently using gmsh 4.5.4. > > (Please note that I had to change the file extension to escape institutional > spam filters. It is really a python script.) > > Any insights would be much appreciated. > > Thanks very much, > > Peter. > > Associate Professor Peter Johnston (FAustMS, FIMA) > School of Environment and Science > Griffith University | Nathan | QLD 4111 | Technology (N44) Room 3.19 > T +61 7 373 57748| F +61 7 373 57656 Email [email protected] > <gmsh-prob.png><cap_cut.txt>_______________________________________________ > gmsh mailing list > [email protected] > http://onelab.info/mailman/listinfo/gmsh — Prof. Christophe Geuzaine University of Liege, Electrical Engineering and Computer Science http://www.montefiore.ulg.ac.be/~geuzaine
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