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June 30, 2014, 05:28 |
how to handle non-closed surfaces in STL
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#1 |
Member
DongHo
Join Date: Jul 2013
Posts: 51
Rep Power: 12 |
Hi Foamers
I will use a STL file with snappyHexMesh, though. But I came to know that there were non-closed surfaces on STL file after using surfaceCheck. I know there are some of utilities concerning STL like surfaceHookUp, etc. Which one is the best way to fix the non-closed surfaces? otherwise, I will need to use a third party CAD software? I hope I will be able to handle this matter without using third party programs like ANSA, Hypermesh, etc Please let me know it if you have experiences like that. Thank you. |
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July 1, 2014, 02:27 |
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#2 |
Senior Member
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Hello,
The holes/cracks shall not be a problem if they are smaller than the cell size you apply locally. You can close holes in meshLab, which is a nice open-source tool for processing and editing of surface meshes. Regards, Franjo |
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February 1, 2016, 00:20 |
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#3 | |
New Member
Nila
Join Date: Oct 2014
Posts: 24
Rep Power: 11 |
Hi Dustin. I know it is a very old thread. But I really need help. I need to mesh a wedge shaped geometry. I have seven different patches for that. I am willing to use snappy hex mesh. I prepared 7 different stl files. But when I used cat command, the single stl file is not closed. What should I do now. Please help me.
[Moderator note: moved from http://www.cfd-online.com/Forums/ope...hexmesh-2.html] ________ When I join my stl files of different boundary patches the joined surface is not closed but it should be. What should I do now. Please help me. [Moderator note: moved from http://www.cfd-online.com/Forums/ope...surface-2.html] ________ Quote:
I have the same problem. I have prepared 7 different stl files for 7 boundary patches. But when I check to see if they together make a watertight body it says not all surface closed. In Meshlab I could not see any holes. Can you please help me how I can solve this problem? Last edited by wyldckat; February 6, 2016 at 05:44. |
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February 6, 2016, 05:47 |
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#4 |
Retired Super Moderator
Bruno Santos
Join Date: Mar 2009
Location: Lisbon, Portugal
Posts: 10,975
Blog Entries: 45
Rep Power: 128 |
Quick question @zannatul: What does this command give you?
Code:
surfaceCheck your_stl_file_name.stl
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February 8, 2016, 16:13 |
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#5 |
New Member
Nila
Join Date: Oct 2014
Posts: 24
Rep Power: 11 |
Hi Bruno
Thanks for your response. Earlier surface check command was showing that surface is not closed. Now I have solved the problem and its showing surface is closed, all surfaces are connected to two faces. |
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March 20, 2016, 21:40 |
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#6 |
New Member
Thazin
Join Date: Mar 2016
Posts: 8
Rep Power: 10 |
Hi zannatul!
I hv a problem juz like you..how did you do that...plz advice me.... |
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March 23, 2016, 01:49 |
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#7 | |
New Member
Nila
Join Date: Oct 2014
Posts: 24
Rep Power: 11 |
Quote:
At first I was exporting my CAD geometry in stl format and then I was dividing it into different patches. I had a very fine opening in my geometry and by exporting it in stl format I was not being able to find that hole. Then I exported it in step file format. After that when I selected my patches I could identify where is the problem in my geometry. So I Redraw my geometry and could export different patches directly from solidworks. Then I used cat commend and checked again. It was closed. I hope this could help you. Good luck! Zannatul |
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April 14, 2016, 15:38 |
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#8 |
New Member
Thazin
Join Date: Mar 2016
Posts: 8
Rep Power: 10 |
Thanks!!
But I'm not like you cuz I'm using meshlab. And I can't redraw my geometry because it's changed DEM( digital elevation model) into stl format. |
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April 14, 2016, 15:57 |
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#9 | |
Super Moderator
Tobias Holzmann
Join Date: Oct 2010
Location: Tussenhausen
Posts: 2,708
Blog Entries: 6
Rep Power: 51 |
Quote:
you are right that if the cell size is bigger than the gap it should not be a problem BUT after the last few years I realized that you can get crazy meshing results if you have non-closed stl's. My collegue also used non closed STL's (complex casting stuff) and got crazy results and unexpected behavior all the time. After I fixed the STL with my tools (Blender + SALOME), meshing was so nice and the results. I only can recommend to have a good triangulated (not CAD exported) STL. Anyway this is my personal opinion (: For reparing you can use SALOME or BLENDER. PS: If someone send me a case to check and I see that the surfaceCheck gives a not closed surface, I will not investigate further (:
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Keep foaming, Tobias Holzmann |
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January 9, 2019, 13:26 |
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#10 |
New Member
David
Join Date: Oct 2018
Posts: 27
Rep Power: 7 |
Hi together
I think I have a similar problem with my STL's. I created my geometry with Autodesk Inventor and then imported it to Salome to subdevide some regions and export them as STL like in this video https://www.youtube.com/watch?v=ObsFQUiVi1U&t=180s . Now the problem is that after I've used the cat tool in Linux on my subdivided regions and used surfaceCheck on it it says that the surface is not closed. But when I check the whole STL from Salome it says the surface is closed. So I guess the problem is somewhere in the cutting process with salome. I've tried to fix it with meshlab but there I don't even see any holes. Is it possible that there went something wrong in the cat process? I would be very thankful if someone would be so kind and take a look at my STL. triSurface.zip Edit: found this post of you and will try it this way first https://www.cfd-online.com/Forums/op...sh-salome.html Edit 2: Well it works but only if I just use groups of faces. Not when I use operation tools like cut, fuse and so on. Isn't that possible? Last edited by Fool; January 10, 2019 at 10:46. |
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