Hi, I would like to know how to extract physical surface label for a 2D mesh define on Gmsh. For example, a square domain composed of 4 sub domains (with physical tag 1,2,3 and 4) : I would like to be able to integrate on each of these subdomain (dx(1), dx(2), dx(3) and dx(4)). I naively tried …

Dokken, I really appreciate your help and advice. Thank you very much and have a good day.

Hi, I’m sorry to bother you again with this question but it I cannot make it work again. What did you take for “subdomain” in your lines of code below? V = FunctionSpace(mesh, "DG", 0) f = Function(V) f.vector()[:] = 1.5*(1==subdomains.array()) + 50*(2==subdomains.array()) + ... When I choose “s…

Hi, You need to load your data as described in the post above. mvc = MeshValueCollection("size_t", mesh, 2) with XDMFFile("mf.xdmf") as infile: infile.read(mvc, "name_to_read") mf = cpp.mesh.MeshFunctionSizet(mesh, mvc) So subdomains would be equal to mf

Thank you very much (I wrote your mf file under two different files “mf” and “cf” and I tested only mf…) That’s working. Sorry for this trivial question.

I think this does not work anymore? I am trying to repeat this example but stuck with this part of the code. I will write down what I have done so far. Write xdmf file for surfaces and boundaries with the most recent working script that I can find: import meshio import numpy as np msh = meshio.re…

Actually that is also me :slight_smile: But this time I am trying to define multiple Physical Surfaces inside the domain as in this problem. Physical Lines do not cause a problem but dividing the domain and marking different regions is a problem.

My point is that: You are using an old and very complicated way of converting meshes (that is known to be error prone). The links in the previous posts shows you how to tag both surfaces and volumes. Without a reproducible example, there is not much we can do to help you

I will be using FEniCSx someday for sure. Unfortunately I have to stick with Docker Toolbox and some older scripts for at least a couple of months. Here is the .geo for a rectangle divided to two in gmsh and exported as Version 4 ASCI II: Point(1) = {0, 0, 0, 0.1}; Point(2) = {1, 0, 0, 0.1}; Point…

[image] meteoguc: I will be using FEniCSx someday for sure. Unfortunately I have to stick with Docker Toolbox and some older scripts for at least a couple of months. Consider Mesh generation and conversion with GMSH and PYGMSH | Jørgen S. Dokken

How to extract and use physical labels from GMSH surfaces on FEniCS (2D mesh)

mesh

dokken July 22, 2022, 8:01am 15

See the links in: Marking the boundaries of a 2D mesh for a mixed function-space problem - #4 by dokken

Topic		Replies	Views
Working with different subdomains: from meshio to dolfin mesh	10	2384	March 11, 2021
Different behaviour of a mesh coming from generate_mesh() resp. UnitSquareMesh()? mesh	30	5667	January 18, 2021
How to use gmsh tags to assign material properties? mesh	7	1833	September 13, 2022
How to import xdmf mesh generated by gmsh into fenics General	27	2900	January 20, 2023
Accessing and marking imported boundaries mesh	9	3165	May 12, 2021

How to extract and use physical labels from GMSH surfaces on FEniCS (2D mesh)

Related topics