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[Sponsors] |
October 31, 2007, 02:50 |
Dear Doug,
Since I have only
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#21 |
Senior Member
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Dear Doug,
Since I have only several days to finish meshing, I would like to accept your advise, using hex for my case. I'll let you know my progress. Thank you. Zhou Bin |
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October 31, 2007, 03:43 |
Dear Doug,
I am really impr
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#22 |
Member
Tommaso Lucchini
Join Date: Mar 2009
Posts: 87
Rep Power: 17 |
Dear Doug,
I am really impressed by the capabilities of Blender and Calculix together and I would like to start using them as meshing tools. Before starting, I have a couple of curisosities about them: 1) Are you using them for only 2d meshes or also 3d? 2) Which kind of geometries are you modelling? 3) Could you post a couple of images of some meshes? 4) What about the mesh quality (skewness/non-orthogonality)? Thanks a lot, Bye Tommaso |
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October 31, 2007, 04:23 |
Doug,
I forgot the last qu
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#23 |
Member
Tommaso Lucchini
Join Date: Mar 2009
Posts: 87
Rep Power: 17 |
Doug,
I forgot the last question: have you ever tried meshing STL surfaces with Blender? Thanks again, Tommaso |
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October 31, 2007, 05:24 |
Dear Doug,
When I install Cal
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#24 |
Senior Member
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Dear Doug,
When I install Calculix, and go ahead one by one according to the installation, but at step 8, after I type: cgx -b dummy.fbd. the system tells me that: the input file dummy.fbd can not be opened. I stop here and have done this for two days. Kindly, Zhou Bin |
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October 31, 2007, 06:40 |
Tommaso,
Q1) Are you using
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#25 |
Member
Doug Baldwin
Join Date: Mar 2009
Posts: 53
Rep Power: 17 |
Tommaso,
Q1) Are you using them for only 2d meshes or also 3d? A1) Blender for 2-D compound curve surface, then extrude in Calculix for 3-D external flow. Q2) Which kind of geometries are you modeling? A2) Concave/convex surfaces, beginning to use what has been called manifolds for joining multiple meshes. The Python tool I posted in a separate thread works great for external flow over uniformly convex bodies of revolution. Q3) Could you post a couple of images of some meshes? A3) Everything I have done is private. I'm currently working overtime on one project. Perhaps in the next month I'll have free time to create a public example. Q4) What about the mesh quality (skewness/non-orthogonality)? A4) For highly curved surfaces where extrusion is not orthogonal, I can pass all meshCheck except nonOrthogonal warnings. I must iterate between Blender/Calculix/OpenFOAM to achieve this quality, and its becoming faster for me so that maybe in about 4-5 iterations I have a high quality mesh. Also, subsurf in Blender has generated one or two warped surfaces warnings. For flat surfaces with orthogonal extrusion, no errors or warnings. Q5) STL? Q5) I once imported an STL into Calculix, extruded it, then meshed it with hex. Looked kinda funny, even passed meshCheck, but I didn't run the solver. Blender has the ability to import/output an STL, which I have used on occasion as a template for creating a subsurf with square elements. I prefer square and hex. Doug |
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October 31, 2007, 06:47 |
Zhou Bin,
> input file dumm
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#26 |
Member
Doug Baldwin
Join Date: Mar 2009
Posts: 53
Rep Power: 17 |
Zhou Bin,
> input file dummy.fbd can not be opened. This is correct. Calculix needs a filename to start running. If you then create geometry in Calculix and Save, your geometry will be saved in dummy.fbd . This and more is covered in the tutorial that is provided with Calculix. Doug |
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November 1, 2007, 16:16 |
Dear Doug,
Here we have a fes
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#27 |
Senior Member
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Dear Doug,
Here we have a festival in Italy, so I'm sorry I could not reply you immediately. Now I can see that this is not a problem, and I can go ahead. Thank you. By the way, the geometry you post entitled " Image of surface mesh" is quite well, and I'd like to use this way, but afterwards you post on Saturday, October 13, 2007 - 12:11 pm, the mesh is different. Because at first the circle is made from rectangle, How you make another rectangle around the circle for mesh in your first case? Or just like the usual way? |
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November 1, 2007, 16:30 |
Dear zhoubin,
are you worki
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#28 |
Member
Tommaso Lucchini
Join Date: Mar 2009
Posts: 87
Rep Power: 17 |
Dear zhoubin,
are you working with OpenFOAM and Blender in Italy? Is it possible to know which is your company/university? Thanks a lot, Tommaso |
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November 2, 2007, 02:27 |
Dear Tommaso:
I am a student
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#29 |
Senior Member
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Dear Tommaso:
I am a student here in Politecnico di Torino, nice to meet you. Best regards, Zhou Bin |
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November 2, 2007, 07:14 |
Zhou Bin,
Good. The square
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#30 |
Member
Doug Baldwin
Join Date: Mar 2009
Posts: 53
Rep Power: 17 |
Zhou Bin,
Good. The square around the square allows you to control the mesh at the boundary of the circle. That too is the way I'd do it. The simple technique is to set the Pivot to Midpoint, in Edit Mode select one square, then press the "E"-key to Extrude. Press <escape> so that the extruded square keeps the same dimensions as the original square, then press the "S"-key to scale the square about the midpoint pivot. I'm on travel through mid-next week. You should be able to locate a tutorial on Extrusion. The one trick not usually taught is <esc>, then S-key to scale the extrusion. Doug |
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November 2, 2007, 10:26 |
Dear Doug,
First have a nice
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#31 |
Senior Member
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Dear Doug,
First have a nice trip. I'll show you what I have done during your trip next week. Best regards, Zhou Bin |
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November 18, 2007, 20:35 |
Dear Doug,
OpenFOAM has a p
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#32 |
Senior Member
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Dear Doug,
OpenFOAM has a period of no function, and between this time, I have posted my current situation here. Now, I want to tell you that I have solved the problem of 4 z just as you said. Really thank you. After I select the boundary with the command qadd and qrem, I have many files, however, in the 4 files: boundary, cells, faces and points, I could not find the boundary I selected. But in the files I saved, which is named as "holewithin.fbb". Do you generate the file "boundary" which can contain the selected boundary? Best regards, Zhou Bin |
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November 18, 2007, 20:47 |
Dear Doug,
in the parent di
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#33 |
Senior Member
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Dear Doug,
in the parent directory of project, I input: checkMesh .project, but an information tells me: FOAM FATAL ERROR:Wrong number of arguments, expected 2 found 1. I don't know if you have this kind of problem or not? Best regards, Zhou Bin |
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November 19, 2007, 08:38 |
I check the mesh from Calculix
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#34 |
Senior Member
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I check the mesh from Calculix to openfoam, but I get the following information:
root@openfoam:~/OpenFOAM/root-1.4.1/run# checkMesh .filter /*---------------------------------------------------------------------------*\ | ========= | | | \ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \ / O peration | Version: 1.4.1 | | \ / A nd | Web: http://www.openfoam.org | | \/ M anipulation | | \*---------------------------------------------------------------------------*/ Exec : checkMesh .filter Date : Nov 19 2007 Time : 14:17:22 Host : openfoam PID : 6527 Usage: checkMesh <root> <case> [-parallel] [-fullTopology] [-cellDeterminant] [-pointNearness] [-latestTime] [-time time] --> FOAM FATAL ERROR : Wrong number of arguments, expected 2 found 1 FOAM exiting After several hours check, I still could not find the reason. |
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November 19, 2007, 11:01 |
Dear Zhou,
you should run:
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#35 |
Member
Tommaso Lucchini
Join Date: Mar 2009
Posts: 87
Rep Power: 17 |
Dear Zhou,
you should run: checkMesh . filter and not checkMesh .filter bye |
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November 20, 2007, 03:59 |
Dear Tommaso,
Last night I
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#36 |
Senior Member
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Dear Tommaso,
Last night I had the same solution like you suggest, this morning I tried, and I got: ---------------------------------- Exec : checkMesh . filter Date : Nov 20 2007 Time : 08:00:07 Host : openfoam PID : 5462 Root : /home/zhou/OpenFOAM/root-1.4.1/run Case : filter Nprocs : 1 Create time --> FOAM FATAL IO ERROR : cannot open file file: /home/zhou/OpenFOAM/root-1.4.1/run/filter/system/controlDict at line 0. Function: regIOobject::readStream(const word&) in file: db/regIOobject/regIOobjectRead.C at line: 66. FOAM exiting ------------------------------------ I'm searching and thinking about this problem. Best regards, Zhou Bin |
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November 20, 2007, 05:22 |
Dear Tommaso,
I have solved t
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#37 |
Senior Member
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Dear Tommaso,
I have solved this problem, and I would like to post it here, hope it is useful for others: I copy controlDict from icoFoam, then I change some parameters inside use "gedit ..." Now it is ok. Best regards, Zhou Bin |
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November 27, 2007, 04:30 |
Dear Doug,
I am very glad t
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#38 |
Senior Member
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Dear Doug,
I am very glad to tell someone else who has the similar model with me that: after I use gmsh for meshing, I am impressed by the power of gmsh---- a powerful tool with simple platform. I could control the mesh around each circle very easily and mesh them for one click. Sincerely thank you for introducing me Blender for a long way. Best regards, Zhou Bin |
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