Scripted Mesh Generation Software

Question

I'm looking for a mesh generation software that

is free and open source,
provides a sane scripting interface for domain specification,
works for complex geometries,
can generate 2D and 3D meshes,

What options do I have?

score 10 · Answer 1 · answered Jun 04 '13 at 18:10

10

I would recommend you look at gmsh. It has both text and CAD-like input, capable of 2D and 3D, higher order meshes. It is licensed under the GPL, so there are some restrictions on integrating it into closed source software, but is otherwise completely free/open-source.

answered Jun 04 '13 at 18:10

Godric Seer

4,637
2
23
38

Unfortunately, the scripting language is insane. ;) – Nico Schlömer Jun 04 '13 at 18:11
In what way? Are you refering to the text file inputs, or some other interface? – Godric Seer Jun 04 '13 at 18:17
The text input indeed. Variables are replaced by integer identifiers that you have to manage yourself, Functions are really macros, and if you make one mistake in handling the points/lines/surfaces, Gmsh often just segfaults. At least that is my experience. It is interesting to hear that it seems to work out well for you though. – Nico Schlömer Jun 04 '13 at 18:23
2

I have only used gmsh in someone simple-ish geometries since my problems are almost always complicated by factors other than geometry. While I have only worked on these simpler geometries, I definitely found gmsh to be the most intuitive and easiest to learn. I won't argue with you though about trying to do more complicated procedures since I don't have experience with them. – Godric Seer Jun 04 '13 at 18:28
5

You can always write your scripts in whatever language you like and simply create files as a result of your script that are then fed as inputs to gmsh. – Wolfgang Bangerth Jun 05 '13 at 10:34
gmsh has one big advantage - you can link libraries in your own software and use as an object in your software. The basic API is pretty straight forward. – Krzysztof Bzowski Jun 05 '13 at 13:41
1

@WolfgangBangerth I actually started a little toy project in Python on https://github.com/nschloe/python4gmsh. – Nico Schlömer Oct 03 '13 at 21:53
gmsh supports 'newp' and 'newl' to allocate identifiers dynamically. See http://www.geuz.org/gmsh/doc/texinfo/#t5_002egeo for examples – lurscher Dec 04 '13 at 17:47

aterrel · Answer 2 · 2013-06-05T13:44:08.293

4

I usually use tetgen for 3D (MIT license for research/non-commercial) and triangle for 2D (Custom license free for non-commercial). To script them, you write a input file and call the command line.

edited Jun 05 '13 at 13:44

answered Jun 04 '13 at 22:07

aterrel

3,644
24
26

2

"Please note that TetGen is free for research and non-commercial uses. For any commercial utilization, a commercial license is available upon request." -- This is not a free or open source software license (under OSI or FSF definition), let alone an MIT license. – Jed Brown Jun 05 '13 at 04:25
Yes I just read the first bit of the License file. Most people are not as strict in their meaning of Free as the OSI or FSF. – aterrel Jun 05 '13 at 13:41
I was about to ask a similar question. Is tetgen compatible with FEniCS? – seb Jun 05 '13 at 14:10
@aterrel Read the LICENSE file: "This means that TetGen is no free software, but for private, research, and educational purposes it can be used at absolutely no cost and without further arrangements." – Jed Brown Jun 05 '13 at 14:16
1

Yes, @JedBrown, I agreed with you and edited the response. But to the laymen, free usually means "I don't have to pay for it" not the RMS legalize. I would also argue that GPL is not "free" but that is probably not an appropriate discussion for this forum. – aterrel Jun 05 '13 at 14:55
@sebastian Depends what you mean by compatible. It is not compatible with LGPL which is what most of FEniCS is licensed as. IANAL: my understanding is for non-commercial products you are fine mixing the two. – aterrel Jun 07 '13 at 14:14

score 3 · Answer 3 · answered Jun 27 '13 at 14:33

3

MeshPy can be used for obtaining triangular and tetrahedral meshes. It provides an easy means of scripted mesh generation.

MeshPy provides Python interfaces to Triangle and TetGen mentioned by aterrel.

answered Jun 27 '13 at 14:33

Subodh

1,480
14
31

score 2 · Accepted Answer · answered Apr 10 '18 at 09:54

2

In the meantime, I created

pygmsh as a Python front end for gmsh and
pygalmesh as a Python front end for CGAL's 3D meshing capabilities.

Both are fairly well received, so I'm guessing they are helpful to others as well.

answered Apr 10 '18 at 09:54

Nico Schlömer

3,126
17
36

score 1 · Answer 5 · answered Mar 29 '17 at 12:12

1

OpenSCAD fits all points except volume meshing. It is based on input scripts and generates STL surface meshes.

answered Mar 29 '17 at 12:12

Dohn Joe

559
2
9

Riccardo Volpe · Answer 6 · 2018-08-13T16:15:09.397

1

Why not Blender? It is a powerful, free and open-source software with python scripting support too.

In Blender 2.79 you need to choose Scripting as Screen layout.

In the top-left Text Editor press + to create a new text data-block; start it with import bpy and then insert the python commands relative to each operation that you can do from the GUI, reading the relative command putting your mouse over the GUI item.

In the attached screenshot are shown the commands to triangulate a circle, starting from the default scene with a cube:

In this way, you can use Blender in scripting mode, without its GUI to export, for example, an output file, running your python script in a terminal:

blender --background --python myscript.py

Here a videotutorial on YouTube.

Cheers

edited Aug 13 '18 at 16:15

answered Mar 31 '17 at 00:19

Riccardo Volpe

111
3

Blender can do this? Never knew. How would I triangulate, for example, a circle? – Nico Schlömer Mar 31 '17 at 08:32
@ChristianClason: How is this not an answer? It addresses the question. You can complain that it lacks detail or even that it is wrong, but that’s what downvotes are for. It certainly isn’t a comment. – Wrzlprmft Mar 31 '17 at 10:50
@Wrzlprmft Thanks a lot. I think that could be good if I will provide to Nico Schlömer a detailed videotutorial, writing the essential code here. But in the meanwhile, I can link a topic written by myself times ago in Italian language, asking for an help to export a mesh by using Blender's scripting (that website has been updated, for which some resources are not more available):
https://www.blender.it/forums/topic/difetto-texture-file-obj-da-wrl/

Here an example of videotutorial on YouTube:

https://www.youtube.com/watch?v=K0yb4sZ7B4g
– Riccardo Volpe Mar 31 '17 at 16:46
If you have something to add to your question, please [edit] it in. – Wrzlprmft Mar 31 '17 at 16:48

score 1 · Answer 7 · answered Jun 27 '13 at 14:11

1

I have found Salome to be very flexible, with a much better environment than gmsh. It has a much more professional feel IMHO. Moreover, it can generate also hexahedral meshes. It is really worth a try!

answered Jun 27 '13 at 14:11

FlatronL1917

111
1

I don't like the fact that nothing in the geometry model is editable from either UI or Python console. Basically if you want to do changes you need to delete and recreate. That adds a lot of overhead during design – lurscher Dec 04 '13 at 17:49
This is true if you import a geometry given to you in a STEP file for example. But if I am not mistaken, this is also true for the other programs mentioned here! Moreover, if you have the HDF file or the python dump script, you can surely change anything. – FlatronL1917 Jan 07 '14 at 13:14

Scripted Mesh Generation Software

7 Answers7