[s195404]

Dear list,

After many years of using Gambit and FIDAP, I happily find myself learning OpenFOAM. My application is in modelling flow and dispersion around buildings in the atmospheric boundary layer.

With Gambit, the approach to constructing my geometry was to create points, then lines, then faces, then shells, then volumes. I could easily name a roof, walls, opening, inlet, etc. I don't know if this is the best approach, but it's certainly one that I am very familiar with.

A lot of the tools for making (STL-based) geometry, however, seem to use a very different approach - generate regular solids, manipulate them in some way, and then connect them together to form the required shape(s). I'm not at all sure how individual faces are named.

I have seen and tried a variety of free and open source products (gmsh, salome, blender, discretizer, FreeCAD, Google SketchUp) but have found them 1) very lacking in documentation or applications relevant to my particular field, 2) using an approach very different from Gambit, and/or 3) very difficult to learn and use. Proprietary products like CATIA, Hypermesh, ANSA, etc, appear to do much more than I require, also use an unfamiliar paradigm, and are priced very much at the enterprise end.

On the other hand, I have seen products like Rhino 3D, Alibre Design, TurboCAD, etc, which are reasonably priced, but they too use a paradigm very different from Gambit. In addition, I can find nothing more than the briefest mention of them for applications in pre-processing for CFD.

Enough rambling from me. Here are my questions. What kind of mid-priced, commercial tools have list members used to construct and export (via STL) their bluff body geometry for CFD programs (especially OpenFOAM)? Can you refer me to any relevant case studies or documentation?

I would greatly appreciate any input that readers could kindly provide. Thank you in advance.

Regards,

Andrew Ward

PS. I posted a more specific question about Rhino 3D the other day (http://www.cfd-online.com/Forums/ope...-geometry.html), but really should have asked this more general one.

[akidess]

It's not clear from your post - but Gambit itself is not an option? I believe it is somewhat commonly used with OpenFoam.

[elvis]

Hi,
there are different strategies of modeling
http://en.wikipedia.org/wiki/Solid_modeling
http://en.wikipedia.org/wiki/Freeform_surface_modelling =>Catia can do both ;-)
and if you are free to chose your way of modeling you can decide which CAD program
Moi Moment of Inspiration http://moi3d.com/ "costs 300$" and is somthing in the same direction of Rhinoceros. But not useful when you do solid modeling or parametric design

http://en.wikipedia.org/wiki/List_of_CAx_companies http://en.wikipedia.org/wiki/Computer-aided_design http://en.wikipedia.org/wiki/Comparison_of_CAD_software

[sleepdeprivation]

Pointwise
http://www.pointwise.com/ has the same bottom up philosophy as Gambit. Its a bit easier to use for me. They also support OpenFOAM via direct export, and the sales team is heavily involved in the OpenFOAM community.
Like Gambit, its based around meshing, so its more for meshing geometries you already have than using it for geometry definition. (Although you could make new geometries if you wanted to.)
Its a commercial product, so contact them directly for more information and support.

[s195404]

Originally Posted by akidess

It's not clear from your post - but Gambit itself is not an option? I believe it is somewhat commonly used with OpenFoam.

Thanks for taking the time to respond to my question!

That would certainly be the easiest option. I understand, though, that ANSYS is deprecating Gambit in favour of DesignModeler, if they haven't done so already.

I'm looking for something that will likely have some medium-term future, and with an approach somewhat like Gambit's.

Regards,

Andrew Ward

[s195404]

Originally Posted by elvis

Hi,
there are different strategies of modeling
http://en.wikipedia.org/wiki/Solid_modeling
http://en.wikipedia.org/wiki/Freeform_surface_modelling =>Catia can do both ;-)
and if you are free to chose your way of modeling you can decide which CAD program
Moi Moment of Inspiration http://moi3d.com/ "costs 300$" and is somthing in the same direction of Rhinoceros. But not useful when you do solid modeling or parametric design

http://en.wikipedia.org/wiki/List_of_CAx_companies http://en.wikipedia.org/wiki/Computer-aided_design http://en.wikipedia.org/wiki/Comparison_of_CAD_software

Thanks for this. I'm obviously not much of a CAD user (or thinker), so these links are very helpful.

I'm checking out this software at the moment. It's really great when companies offer short trials of their software.

Regards,

Andrew Ward

[daveatstyacht]

Andrew,
I've always used Rhino for ship hull forms with snappyHexMesh. It has a number of tools that can be used to edit/fix stl meshes, which I have found quite useful and allows pretty good control of the mesh density. It's a few hundred for the commercial version if I recall correctly. I also seem to recall they have a free trial version available that is pretty much the entire program, but with a limited number of saves allowed. Best of luck in your search for the CAD program that suits you best

Regards,
Dave