Hello,

We have developed an open-source mesh generation program named ENGRID; it is licensed under the GPL. The current version (0.9) is in a beta state and we would be happy if people download and try it. It creates unstructured grids with prismatic boundary layers. The prismatic layer generation is a new development, done in-house by enGits, and the tetrahedral part is being created by the NETGEN library ( <a ref=http://www.mathcces.rwth-aachen.de/netgen> http://www.mathcces.rwth-aachen.de/netgen </a>).

Currently the tool cannot create surface meshes, but it can import surface meshes that have, for example, been created by Gmsh ( <a href=http://www.geuz.org/gmsh> http://www.geuz.org/gmsh </a>) or NETGEN.

The ENGRID homepage can be found here: <a href=http://www.engits.com/cms/index.php?id=16> http://www.engits.com/cms/index.php?id=16 </a>.

A very rudimentary documentation is also available.

Any feedback is most welcome!!

Oliver

Hi,

interesting... are there any plans to do hexa as well?

Flo

Unstructured hexas yes -- block structured is a whole different story and not planned so far.

At the moment you can extrude quads and end up with hexas, but you cannot "grow" a hexahedral or mixed boundary layer yet. For the farfield it is also planned to have hexahedral regions (Cartesian, cylindrical, and maybe spherical). To connect the boundary layer to the far field, however, tetras will be required. Ideally there will be a polyhedral connection between boundary layer and farfield (based on the dual mesh of tetras). It all depends a bit on the funding that I manage to get for this project, but at the moment I am reasonably optimistic ...

Why develop another open source mesh generator when we already have so many mesh genertors like gmesh, salome, netgen etc? Is it not better to work on only one or two mesh generators and develop them to the extent that we do not have to pay to ansys no more. Code developers should work on a single platform and destroy these money making monsters.

Your mesh generator looks great by the way but with these documentations it will be an uphill task to understand it.

Good luck,

Regards

This project started a bit out of frustration about not having an open-source mesher that could do boundary layers. After starting my own business, I quickly realised I had plenty of options for CFD-solvers (OpenFOAM, own code, friend's code, etc.), excellent post-processing tools, but no mesh-generator capable of generating grids for Navier-Stokes simulations. Instead of paying for a commercial software I managed to get some funding for this development.

About the lack of documentation: You are right, the documentation is more or less non-existent. I hope that the little tutorial will give an idea about the process and the documentation will hopefully improve as well. It has been tried to keep the mesh generation as simple as possible. For most geometries it boils down to:

(1) define boundary conditions (2) create prismatic layer (3) refine volume grid (4) save grid (5) refine boundary layer (6) export grid to solver

If you would like to try it and get stuck (compilation, usage, import, export, ...), don't hesitate to ask for help.

Thanks for your comments, Oliver

P.S. Does anybody know how to avoid this "WebKitFormBoundaryq2EKBC..." when posting from Safari on a MAC???

Hats off Oliver! I've not had the chance to try your mesher yet, but I am very excited about the prospect. I agree with you regarding a serious lack of open source options. Maybe I just haven't looked hard enough, but despite there being a million and one ways to generate a tet mesh open source, none of the others seem to deal with boundary layers. For my purposes (turbomachinery) - that makes them useless!

I currently have access to myriad academic and commercial meshers since I'm studying. However, the company who sponsor my work are really sick and tired of paying ANSYS so much and are actively looking at ways of using open source.

Thanks for the comment - feel free to try it and in case of problems don't hesitate to ask for help (contact details are on the website).

While there are many free meshers available, none of them can do boundary layers. So this is a valuable addition to open source meshers. I hope to test it soon.

Can it be compiled on a Mac ?

In theory yes -- the only MAC I have available is a laptop which is a couple of years old, though. Did you manage to compile Qt and VTK on your MAC? If yes, then it shouldn't be too difficult to compile engrid.

I will try it in the evening. I have never compiled VTK on a mac. Is VTK already included in the engrid sources ? I think Qt is already available in Xcode but I dont seem to have qmake. I may have to install it but I have read on the web that there are no problems.

VTK is not included, you have to download it from www.vtk.org. Unfortunately I have no programming experience on Mac OS.

Hi there My knowledge of the linux OpenSuSe is still limited so I downloaded the windows version. The following comment is based on my own personal preferences, hope it will be read as such, now since the enGrid reads geometry files produced by Gmsh (which is open source too) I wonder if your future plans contemplate the possibility of including a geometry creation menu which is based on Gmsh, I prefer to have a mesher that creates its own geometry whether directly or importing it as iges or step file (just like Gambit) I also want to congratulate you on this effort and hope the best for you

[claco]

Originally Posted by Kevin
;55981

Hats off Oliver! I've not had the chance to try your mesher yet, but I am very excited about the prospect. I agree with you regarding a serious lack of open source options. Maybe I just haven't looked hard enough, but despite there being a million and one ways to generate a tet mesh open source, none of the others seem to deal with boundary layers. For my purposes (turbomachinery) - that makes them useless!

I currently have access to myriad academic and commercial meshers since I'm studying. However, the company who sponsor my work are really sick and tired of paying ANSYS so much and are actively looking at ways of using open source.

Dear Sir,

could You please me indicate an opensource software for turbomachinery mesh building?

Yours Sincerely,


Claudio Comis