Add support for subdomains in 3D

[Benjamin Dam Kehlet]

mshr should support subdomains in 3D as well as in 2D with the same user API.

For CGAL this requires implementing a mesh domain class which can * return the subdomain index for a given point. * add the sharp features of the subdomain boundaries when the mesh engine is initialized.

[Adriaan]

@benjamik I'm working with 3D meshes for a while and restricted by the absence of sharp subdomain boundaries in my meshes. Any progress on this issue?

[Joshua Chen]

Will this be available for 2018.1?

[Ryan Haagenson]

I've been using mshr with FEniCS for 2D simulations for a while now. I need to expand into 3D, but need subdomains to facilitate multiple material types in my domain. Any progress on this issue? Is there a known work-around? Thanks.

[Håkon Gabrielsen]

Hi Ryan

Using Gmsh and dolfin-convert is a good work-around for me.

This link helped a lot on retrieving subdomains based on physical regions in Gmsh: https://www.allanswered.com/post/lokwq/

[Matti Masten]

Hi @benjamik -- thanks for your fantastic work on this project.

I was wondering if you have an update for where the 3D subdomain support is at, even if it's that it's no longer a priority. I noticed that you said on Google Groups last year that the merge would only affect the Tetgen backend; I tried using that backend and still got the error, but wanted to make sure that it's not a mistake on my end.

Thanks for any information available, and for a great tool!