Thanks for suggesting PyGmsh! I bumped into it a while ago but never really figured it out. Now I'm keen since it should help building and modifying meshes more easily.

I installed pygmsh easily using the instructions on the website. It imports correctly. There is even an example that builds a circle, I think.

When I try running this, as well as other examples, I get an error because no module named vtk is found. See below. I get this comes from meshio?

Traceback (most recent call last):
File "circle.py", line 24, in <module>
    meshio.write('circle.vtu', *out)
File "/home/fpoulin/software/firedrake/local/lib/python2.7/site-packages/meshio/__init__.py", line 187, in write
    field_data=field_data
File "/home/fpoulin/software/firedrake/local/lib/python2.7/site-packages/meshio/vtk_io.py", line 204, in write
    import vtk
ImportError: No module named vtk

When I do a pip install it tells me that it is already installed and up to date.

(firedrake) fpoulin@fpoulin-Gazelle:~/software/pygmsh/test/examples$ pip install -U meshio
Requirement already up-to-date: meshio in /home/fpoulin/software/firedrake/lib/python2.7/site-packages
Requirement already up-to-date: pipdated in /home/fpoulin/software/firedrake/lib/python2.7/site-packages (from meshio)
Requirement already up-to-date: numpy in /home/fpoulin/software/firedrake/lib/python2.7/site-packages (from meshio)
Requirement already up-to-date: requests in /home/fpoulin/software/firedrake/lib/python2.7/site-packages (from pipdated->meshio)
Requirement already up-to-date: appdirs in /home/fpoulin/software/firedrake/lib/python2.7/site-packages (from pipdated->meshio)

I realize this isn't necessarily a firedrake question but if anyone had an idea on how to get this working I would be keen to try it.

Cheers, Francis
------------------
Francis Poulin
Associate Professor
Department of Applied Mathematics
University of Waterloo

email:           fpoulin@uwaterloo.ca
Web:            https://uwaterloo.ca/poulin-research-group/
Telephone: +1 519 888 4567 x32637

From: firedrake-bounces@imperial.ac.uk [firedrake-bounces@imperial.ac.uk] on behalf of G. D. McBain [gdmcbain@protonmail.com]
Sent: Sunday, March 19, 2017 6:16 PM
To: firedrake@imperial.ac.uk
Subject: Re: [firedrake] circles in firedrake?

I would expect a user to run gmsh separately (at the command line or through the GUI), rather than from within the Python script. I don't think it's possible to interact with gmsh from Python nowadays without jumping through considerable hoops.

Have you tried the (free third-party) PyGmsh? It generates .geo code from Python. From there one calls Gmsh using Python subprocess and reads in the resulting .msh. I've found it handy.

https://github.com/nschloe/pygmsh