Hello,

we are using Nutils to simulate a phase field fracture problem. The code has been working so far as expected on a simple geometry generated using the mesh.rectilinear() function. But now we want to test the code on a multi grain geometry generated using the Neper library. We generated the geometry file in .msh format, but we are running into some errors while importing it. When using the mesh.gmsh() function, we get the error KeyError: 'gmsh:bounding_entities' and error statement looks like:

$ python3 fracture.py 
opened log at file:///home/aravinth/public_html/fracture.py/log-40.html
nutils v6.2 "garak-guksu"
start Mon May 31 08:58:39 2021
KeyError: 'gmsh:bounding_entities'
log written to file:///home/aravinth/public_html/fracture.py/log-40.html

We could not find any documentation on this error. Any guidance on this issue would be helpful. I have attached the mesh file and the block of the source code to recreate the issue. We are running Nutils 6.2.

We also want to evaluate integrals on grain boundaries, which can be considered as curves/lines inside the domain. These grain boundaries are denoted as edges in the .msh file. How would one do this in Nutils? Would a command like topology.boundary['edge1'].integral() work, if the name of the edge is 'edge1' in the .msh file?

Nutils code
Mesh