How to check mesh quality?

mesh
1

Hi everyone

How do I check my mesh is good or not? I found some videos on youtube but they are a little bit advance. If you know some tutorials, please let me know.

Best regards

2

You could try visualising your mesh using eg Gmsh or Paraview.

In what way(s) do you think your mesh might not be good?

3

There are several functions in dolfin to check meshquality, see the API:
https://fenicsproject.org/docs/dolfin/2019.1.0/python/_autogenerated/dolfin.cpp.mesh.html?highlight=meshquality#dolfin.cpp.mesh.MeshQuality,
Which can be import by from dolfin.cpp.mesh import MeshQuality

However, I agree with @mscroggs that Paraview is a very suitable tool for visualizing the quality of the mesh, as it has several filters for this purpose

4

Thank you dokken and mscroggs

I will use Paraview for checking mesh quality.

Do you know where I can find an example or a tutorial for this purpose? And how to fix the mesh after checking it too.

Thank you very much

5

Depending on how you have generated your mesh, that tool might have ways of improving mesh quality (changing meshing algorithms etc).

Which tool Did you use?

6

vtkplotter has methods to measure mesh quality, see here.

import dolfin
from vtkplotter.dolfin import MeshActor, plot, datadir
from vtkplotter import meshQuality

mesh = dolfin.Mesh(datadir + "dolfin_fine.xml")

vtkmesh = meshQuality(MeshActor(mesh)) # wrap mesh
vtkmesh.lineWidth(0.1)

plot(vtkmesh, bg='white')

Screenshot from 2020-01-27 23-29-55
Screenshot from 2020-01-27 23-29-55573×528 200 KB

7

Hi Dokken

I am using gmsh, but I usually take the mesh from others.

8

Gmsh has several meshing algorithms implemented that can change the mesh quality.

It is possible to perturb meshes in dolfin using ALE.move(mesh, pert), Where pert is a CG1 vector function over the mesh. So, if you can Express the change you would like to do as a CG1 function in dolfin, you can modify the mesh there.