Dolfin-convert Diffpack Mesh Assertion Error

Dear Community,

I have been able to import a model from Inventor (Windows 10) STEP file via NETGEN (ElementaryOS) Diffpack to dolfin XML and work with it in Fenics. However certain models for no discernable reason cause a failure in the dolfin-convert throwing an Assertion error:

Convert from Diffpack tetrahedral/triangle grid format to DOLFIN XML.
Expecting 134106 vertices
Found all vertices
Expecting 666259 cells
Traceback (most recent call last):
File “/usr/bin/dolfin-convert”, line 132, in
main(sys.argv[1:])
File “/usr/bin/dolfin-convert”, line 79, in main
meshconvert.convert2xml(ifilename, ofilename, iformat=iformat)
File “/usr/lib/python3/dist-packages/dolfin_utils/meshconvert/meshconvert.py”, line 1301, in convert2xml
convert(ifilename, XmlHandler(ofilename), iformat=iformat)
File “/usr/lib/python3/dist-packages/dolfin_utils/meshconvert/meshconvert.py”, line 1337, in convert
diffpack2xml(ifilename, ofilename)
File “/usr/lib/python3/dist-packages/dolfin_utils/meshconvert/meshconvert.py”, line 947, in diffpack2xml
assert(len(marker_intersection)==1)
AssertionError

I have no idea what this error means and I have attempted to remake several STEP files from AutoDesk Inventor and attempted different settings in NETGEN to no avail. I read a similar post in the old Launchpad forum where someone was experiencing a similar issue but there did not appear to be a solution and was around 7 years old.

Any help will be greatly appreciated.

Many thanks,
Matthew.

Hi, dolfin-convert is no longer maintained, and you should use software such as meshio to convert meshes to dolfin.xml or xdmf (preferred). See Transitioning from mesh.xml to mesh.xdmf, from dolfin-convert to meshio for loads of examples of usage.

1 Like

This is perfect, thank you so much!