Netgen now on Sourceforge
 

Hello and a Good Evening :-)!

I just wanted to inform the OpenFOAM community, that the opensource mesher by Joachim Schoeberl and his team (Netgen) now has its own Sourceforge project entry at:

http://sourceforge.net/projects/netgen-mesher

The latest source code can be downloaded from the SVN repository:

http://netgen-mesher.svn.sourceforge.net

The version available from the repository uses "autotools" to ease compilation, but since it is still being implemented, it would be great if people could try to compile it on their machines, and provide feedback (preferably directly to the Netgen Forum on Sourceforge) when they trip up on something.

Enjoy, and have a nice day!

Philippose

Hello again, A Good Day to
 

Hello again,

A Good Day to everyone :-)!

This is just to add on to the previous post, to inform the OpenFOAM Community, that now the Netgen SVN repository hosted at Sourceforge has been updated with Project files for Microsoft Visual C++ 2005 and 2008 (including the Express Editions :-)!)

The complete functionality of Netgen is now available in both Linux (simple compile via the autotools suite), and Windows.... including the support for OpenCascade (hence, STEP and IGES) files.

In addition, there have been some tweaks to the system:

1. More mesh control in STEP geometry allows the user to limit the mesh size also individually on each face by clicking on the face and specifying the local limit.

2. XDE Support for the Opencascade interface allowing the face colours of the geometry to also be imported (this is currently only cosmetic, but the first step to colour based automation of boundary patch selection)

3. Export of the mesh in the Gmsh v2 format (with suppoert for higher order elements.... though this will not be directly useful in OpenFOAM)

It would be interesting to get something like a "wishlist" from the OpenFOAM users, for improvements, additions and changes... which would be relevant in the context of Netgen as a mesher for OpenFOAM.

Have a great week ahead!

Philippose

Setting up the boundary (by selection Faces) and initial conditions (at the Run Dialog) is very easy in www.discretizer.org
It would be nice to make it as easy in netgen.

Adding on to my initial posts regarding the status of Netgen, the following changes have been made over the last couple of months:

1. Netgen now has a skeletal Mediawiki webpage at Sourceforge (http://sourceforge.net/apps/mediawik...itle=Main_Page), which is intended to become the main portal for the Netgen mesher.

2. Version 4.9.11 is now available.

3. Netgen Windows binaries are available for 32-bit and 64-bit systems, including all the dependencies (The main one being 64-bit versions of the OpenCascade libraries)..... all packaged into an actually working install file (created using NSIS).

4. The API version of Netgen (Nglib) has been extended with more functionality which also includes support for Opencascade geometry (STEP/IGES), which were till now only avaliable in the stand-alone version.


Have a nice day!

Philippose

I forgot to mention the following new features:

1. The maximum mesh size on individual faces can now be explicitly specified when meshing OCC Geometry (STEP/IGES) by using the "Edit Face Mesh Size" menu option under the "Geometry" menu, double clicking on a face, and specifying the allowed maximum mesh size.

2. Netgen now also allows colour based assignment of the boundary patch numbers (but currently only for STEP/IGES... because STL does not support colours).

Basically, Netgen imports any face colours available when a STEP/IGES file is opened, and once the meshing is done, these face colours can be used to automatically assign patch numbers, instead of having to manually click and assign each face.

This can be done in two ways....

a. Automated assignment - In this case, Netgen assigns all faces which did not have any colour assigned as patch number 0, and assigns patch numbers to the rest of the colours based on the number of surface mesh elements of a given colour (larger the number of surface mesh elements, higher the assigned patch number for that colour)

b. Using a user defined profile - In this case, the user specifies the patch number, and the associated (r,g,b) colour for that patch in a file called "netgen.ocf" in the netgen bin folder. This mapping is then used by Netgen to assign patch numbers.


Note.... these features are all still in development, and if anyone has any other bright (but at the same time... generic... not purely OpenFOAM specific) ideas, please feel free to let me know...

Philippose

Hi

It would be nice if Netgen had the possibility to double click the face and assign it to a BC index number, would help a lot when converting to OpenFOAM.

I know the automatic exists, but that's is not always a good approach depending on how complex the geometry is.

Best
Linnemann

Hello Linnemann,

This option does exist in Netgen already.... You will find it in the following Menu:

Mesh -> Edit Boundary Conditions

It pops up a window which shows the currently selected face (or a -1 if no face is selected), and the associated boundary condition number.

A face can be selected by double clicking on the face, and then the assoicated boundary condition can be manually modified.

The automated options are good when you have a large number of boundary conditions to define, and if the colours are always "standardised".... however, as you said.... the manual method is very much required :-)!

Feedback on the the usage of Netgen in connection with OpenFOAM would be great :-)!

Have a nice day!

Philippose

Hi

Thx for clearing that, the problem is that i have a propeller geometry which consists of many faces (<600, see attached) and I would like to select the faces that aren't associated with the propeller (bounding box) and put them in a separate BC's. All the faces of the propeller would then be associated with BC 0.

So at import have a BC that has all faces and as you assign the boundingbox faces to other BC's they will be deselected in BC 0.

Also using the "quad dominated" option in the mesh generates really nice surface mesh, but when doing the volume meshing nothing happens, any idea? This is also the case with Salome (netgen plugin) if I have quads on some of the faces then netgen volume just uses alot of cpu power but no output (ran for 48 hours).

Regards

Ok found the solution to the first problem.

Just assign all faces to a BC number and then reassign the others to their own.

The problem with quads on faces and volume mesh generation is although still an open issue.

Also is it possible to assign faces which should be "quad dominated"?

Regards

Hello again Linnemann,

A Good Evening to you :-)!

Great to see that you were able to solve your problem regarding the boundary conditions.... after posting the message I remembered that I should have also mentioned something about the "all" button which assigns the same BC number to all the faces in the mesh :-)! However.... looks like you found it anyway :-)!

As for the issue with Quad Dominated...... as of now (and I think also for the foreseeable future), the option "Quad dominated" only works for either 2D geometry... or for surface meshes..... it is not possible to create a Volume mesh using a Quad dominated surface mesh.

I guess we should be considering disabling that option when the geometry is 3D and when volume meshing is selected....

I dont know if you have seen it yet.... in the "Meshing Options" menu, you can select which steps Netgen should do when it meshes the geometry....:

1. Surface Meshing
2. (1) + Surface Mesh Optimisation
3. (2) + Volume Meshing
4. (3) + Volume Mesh Optimisation

So, if you select only Surface Mesh or Surface Mesh and Mesh Optimisation, you can use the option "Quad Dominated"..... but not with volume meshing.

Netgen is basically intended to be an automatic "tetrahedral" mesh generator.

Personally I prefer using the Netgen GUI rather than the Netgen meshing library available in Salomé.... the standalone version provides a much larger array of mesh controls.

I am very sorry that the documentation for Netgen is extremely skeletal..... its just that..... the main developer is the head of the computational mathematics department at the RWTH-Aachen...... and I work full-time in the R&D department of a hydraulic company..... hence.... Netgen development necessarily takes priority over Netgen documentation due to lack of free time.

If you have any questions regarding Netgen, the best option would be to post it in the "Help" forum of the Netgen Sourceforge website:

http://sourceforge.net/projects/netgen-mesher


Hope this helps!

Have a nice day ahead!

Philippose

Just a short note for openSUSE users. Some time ago Andrea Florio (anubisg1) and I packaged some CFD tools for openSUSE. Netgen and Engrid are among these, and are available for all the supported versions of openSUSE:

Netgen: http://software.opensuse.org/search?...L&p=1&q=netgen
Engrid: http://software.opensuse.org/search?...L&p=1&q=engrid

Best,

Hi philippose

Thx for the help.

So far things are working ok, although I have a minor program problem which I posted info about on the sourceforge site.

Regards

Hello Alberto,

A Good Evening to you!

Thanks a lot for having created a Netgen package for OpenSUSE. I was discussing with Prof. Joachim last night, and he told me that they use OpenSUSE on their institute systems at RWTH-Aachen.... and that he has seen the Netgen package.

However, he told me that the package uses Netgen-4.9.9. Is there some way of easily repackaging it with the latest version of Netgen? And.... how can one maintain this package so that its always updated? Is it too much work to maintain packages? I have no experience with Linux software deployment....

Or... Are you or maybe Andrea Florio willing to maintain the package for OpenSUSE?

Currently I handle the Windows installer.... and since I am a Fedora user, I was wondering if I should also look into creating RPMs....

Do you use Netgen regularly by any chance?

Have a nice day!

Philippose

The idea is to maintain the package for openSUSE, which makes it quite easy thanks to the openSUSE Build Service (we could potentially build for fedora and other distributions too, but I did not look into that).

Andrea or I will update it shortly, and I'll inform you of the update. We did not notice a new release came out! Sorry about that.

Best,

You find the updated netgen package here :D:

http://software.opensuse.org/search?...1&p=1&q=netgen

Hello Alberto,

A Great (but uncomfortably cold) evening to you :-)!

Wow... that was fast :-)! Thank you very much for the update to 4.9.11!! And I was overjoyed to see that the corresponding "_x64" RPM also exists :-)!! Really cool !!

I hope this helps all those linux users who fall into the category of "linux users" rather than the default expected "linux tinkerers" or "linux developers"!!

I was looking into the RPM build guide for OpenSUSE, and they have also mentioned ways of making "Cross distribution" RPM packages.... which will work for more than one flavour of Linux....

Do you have any experience with this concept?

I shall see if I can find some time to look into it too.... would be very interesting to have one RPM which works on all popular linux distributions....


By the way... one question..... who do I need to contact if I want the link to the Netgen project on the OpenFOAM-Wiki to be updated?

Have a wonderful weekend and thanks once again :-)!

Philippose

Hehe, power of the openSUSE buildservice: one .spec file for all :D

Oh I'm lazy myself. I choose the distribution that provides me what I need, not the one that makes me work harder :cool:

It is basically very simple from what I know. You need to write the .spec file to build the RPM using macros instead than hardcoding names, paths and other information. Once that is done, the buildservice will take care of everything.

For example, with one .spec file we build for all the openSUSE versions with a simple click on the distributions we want to build against, as long as all the dependencies are satisfied. If a build fails for one distribution, the others are untouched.

We do not do that with the openSUSE buildservice. We provide different RPM's for each distribution. You can use the build service to build packages for openSUSE, fedora, ubuntu, SLES, RHEL, CentOS, debian and ubuntu.

Best,
Alberto

Netgen4.9.11 from SourceForge wont run...
 

I have been using netgen4.4 on windows xp

I downloaded the discussed version of netgen at:
http://sourceforge.net/projects/netg...2.exe/download

I installed Netgen-4.9.11_Win32.exe sucessfully, however it will not run.

The error says:
__________________________________________________
C:\Program Files\Netgen-4.9.11_Win32\bin\netgen.exe

This application has failed to start because the application configuration is incorrect. Reinstalling the application may fix this problem.
__________________________________________________

Thoughts? How do I configure it?

Thanks guys!

Hello there :-)!

A Good Evening to you!!

This error usually comes up when you dont have the Microsoft Visual C++ runtime libraries installed.... you need to install both the MSVC++ 2005 and MSVC++ 2008 runtime libraries....

You can find them by either searching on:

http://www.microsoft.com/downloads/en/default.aspx

Or my googling "MSVC++ runtime libraries 2008" and "..... 2005"

Have a nice day!

Philippose

Fixed
 

Your awesome philippose!


That fixed it. Thanks! These are the direct links to the downloads for everyones info:
http://www.microsoft.com/downloads/d...d-074b9f2bc1bf
http://www.microsoft.com/downloads/d...9-220b62a191ee


Now all i have to do is learn how to use it... :)