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Netgen mesh settings for STL geometries

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Old   August 16, 2007, 05:56
Default Hi all, I started using net
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Tommaso Lucchini
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Hi all,

I started using netgen a couple of weeks ago and I found it a very powerful tool considering the high mesh quality it is able to provide for complex geometries.

I wonder if someone in this forum knows the meaning of the following settings in the Meshing Options - Mesh size window:

1) Elements per curvature radius
2) Elements per edge
3) STL - chart distance
4) STL - line length
5) STL/IGES/STEP - close edges
6) STL - surface curvature
7) STL - edge angle
8) STL - surface mesh curv

Any kind of help is very appreciated.

Thanks in advance

Tommaso
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Old   August 16, 2007, 14:26
Default Hello Tommaso, A good day t
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Philippose Rajan
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Hello Tommaso,

A good day to you!

I have been using Netgen for over a year now, and I personally find it to be the best opensource mesher available, by a far call :-)! Nothing comes close to the robustness, ease of use, and bug-free operation of the program!!

However, as you have found out, documentation is not really the strong point of the program :-)! I have tried to contact Joachim Schoeberl with exactly the questions you have posted, but have not got a reply yet (and that was almost a year ago :-)!)

Anyway... off-late, I have started scouring the source-code of Netgen, first, to understand what each of those parameters mean, and then, to understand how it works, so that I can tweak it up.

For example, my idea is to try and implement a modified "Ruppert-Shewchuk" algorithm which I found in a paper, which overcomes one of the biggest problems of Netgen... its in-ability to control the mesh length scale at places where there are surfaces close to each other in a satisfactory manner.... it always ends up with just one layer of cells between the two surfaces, which ofcourse, is not good for CFD.

Now... so far I have only documented the functioning of the parameters in my head, but I think the time has come to try to make a document which explains the things I have (hopefully) understood. I hate documentation though!!

How quickly do you need answers to your query? Would it be ok, if I try to come up with a PDF, instead of trying to explain things here? It will take some time though :-)! I started typing it out here on the forum, but then cut-pasted it into a "tex" file.

Have a nice day!

Philippose
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Old   August 16, 2007, 14:46
Default Hi Philippose, thanks for y
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Tommaso Lucchini
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Hi Philippose,

thanks for your kind reply. A pdf file about netgen would be really helpful for lots of users. Take your time to do it, there is no hurry.

Thanks again,

bye

Tommaso
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Old   March 7, 2011, 02:02
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vikraman
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dear mr Philippose Rajan

i am vikraman i am trying to generate a volume mesh from an stl file
with netgen, initially it did once but it started crashing when completing about 99% of generation saying run time error i hav upgraded windows from 32 bit to 64 bit and have amd phenom quad core with 8gb ddr3 ram machine i have tried all my best even sent mail to
joachim no any reply from him
can you pls help and suggest how to over come the problem
thk u
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