Volume meshing surface meshes with intended holes.

I have a surface mesh which has a hole. I looked around, but found no info on flags or special commands needed to process such meshes. To generate the volume mesh, I run the script:

import netgen.meshing as meshing
mesh = meshing.Mesh()

The mesh (srfmsh_in_2.vol) seems clean - netgen doesn’t complain, and it is not a huge mesh (~63K faces). After ~1/2 hour, several notifications “start tetmeshing”, and many ‘Smooth Mesh’ steps noted in the gui pane . . . netgen dies. I include the output below.

Any pointers?


Developed by Joachim Schoeberl at
2010-xxxx Vienna University of Technology
2006-2010 RWTH Aachen University
1996-2006 Johannes Kepler University Linz
Including OpenCascade geometry kernel
optfile ./ng.opt does not exist - using default values
togl-version : 2
OCC module loaded
loading ngsolve library
Using Lapack
Including sparse direct solver Pardiso
Including sparse direct solver UMFPACK
Running parallel using 4 thread(s)
importing NGSolve-6.2.1707-81-g909f6c6e
(should) load python file ‘script_2.py’
generate vol mesh

Meshing subdomain 1 of 1
Delaunay meshing
start tetmeshing
start tetmeshing
start tetmeshing
start tetmeshing
start tetmeshing
start tetmeshing
start tetmeshing
start tetmeshing
start tetmeshing
start tetmeshing
Traceback (most recent call last):
File “”, line 5, in
RuntimeError: Caught an unknown exception!
Finished executing script_2.py

Could you post the surface mesh somewhere so we can have a look? What do you mean by holes in the surface mesh? How shall they be volume meshed?



The file is attached.



The (apparent) answer to my question is that no flags or settings are needed by netgen to mesh a surface mesh with a hole, as with the file I sent you.

Although netgen didn’t tell me of mesh problems, nor did I see any problems using meshlab (but I don’t now much about either code); I used some code that cleans surface meshes. After doing that, I did get a volume mesh out of netgen.

I don’t know everything that ‘cleaning’ code does to the mesh, which is a concern - but that is my problem.

Thanks again,