Error while importing mesh with two solids

[Jiahao Ba]

hello

I encountered difficulties importing a mesh model with two parts. The error message is shown below.

An error occurred in line <2594> of file </home/kkl/workspace/dealii/tmp/unpack/deal.II-v9.5.2/source/grid/tria.cc> in function
Static void deali:: internal: TriangulationImplementation:: Implementation:: process_subcelldata (const deali:: internal: TriangulationImplementation: CRS<T>&, Dealii: internal: TriangulationImplementation: TriaObjects&, const std:: vector<dealii: CellData<dim>>&, const std:: vector<dealii: Point<spacedim>>&) [with int structdim=2; int spacedim = 3; T = unsigned int]
The violated condition was:
boundary_id != numbers::internal_face_boundary_id

I find that deleting the units on the interal face between two solids can solve this problem, but I would like to know if there are any other solutions.

[Wolfgang Bangerth]

Jiahoa:

> I find that deleting the units on the interal face between two solids
> can solve this problem, but I would like to know if there are any other
> solutions.

The problem is that you are setting a boundary indicator for a face that
is not actually at the boundary. This can't work. As you found out,
deleting the part of the input file that sets these boundary indicators
works; I don't know whether there is a more elegant way short of telling
the mesh generator to not put boundary information into the mesh file
for faces that are not actually on the boundary.

Best
W.