CFD Online Discussion Forums

CFD Online Discussion Forums (http://www.cfd-online.com/Forums/)
-   STAR-CCM+ (http://www.cfd-online.com/Forums/star-ccm/)
-   -   non-manifold error (http://www.cfd-online.com/Forums/star-ccm/95315-non-manifold-error.html)

vinvalt December 13, 2011 10:44

non-manifold error
 
I want to obtain my fluid domain by either extracting the internal volume or using the boolean operation substract or intercepts on my geometry which I imported under; import CAD Model. However all my attempts resulted in error stating on one hand,
"feature execution failed, non manifold body extracted"
and on the other hand,
"feature execution failed, substractbodies: substract will produce non manifold body"
can you help me with a step by step method of dealing with these two scenarios so as to obtain the fluid domain.

Also what are the steps for dealing with free edges and non-manifold edges and vertices

vinvalt December 13, 2011 10:46

Quote:

Originally Posted by vinvalt (Post 335684)
I want to obtain my fluid domain by either extracting the internal volume or using the boolean operation substract or intercepts on my geometry which I imported under; import CAD Model. However all my attempts resulted in error stating on one hand,
"feature execution failed, non manifold body extracted"
and on the other hand,
"feature execution failed, substractbodies: substract will produce non manifold body"
can you help me with a step by step method of dealing with these two scenarios so as to obtain the fluid domain.

Also what are the steps for dealing with free edges and non-manifold edges and vertices

I want to obtain my fluid domain by either extracting the internal volume or using the boolean operation substract or intercepts on my geometry which I imported under; import CAD Model. However all my attempts resulted in error stating on one hand,
"feature execution failed, non manifold body extracted"
and on the other hand,
"feature execution failed, substractbodies: substract will produce non manifold body"
can you help me with a step by step method of dealing with these two scenarios so as to obtain the fluid domain.

Also what are the steps for dealing with free edges and non-manifold edges and vertices

willimanili December 13, 2011 12:28

Use the surface repair tool to fix your imported geometry before doing any operation on it. Or you can also go back to your CAD and export an valid geometry.

By the way, why dont you look up the user guide for that?! Usually this way is much more faster than post an thread and wait for answer.

vinvalt December 19, 2011 12:35

Thanks for the input. Yes I did read from the manual and did some tutorials on this but it does not help my understanding. That is why I seek your input.
I know of the surface repairs tool but how to repair the geometry after diagnosis is not clear to me when free edges, non manifold vertices , edges etc... are present. can you clarify this to me. I also know that the automatic repair tool will change much on my geometry and I will not like to apply this method and even when I tried most of the errors were not fixed by it. Is there any way round my concern.
Can you explain to me how to export a "valid geometry"

willimanili December 21, 2011 08:27

I dont know which format for import you use, but i think it is an .iges-file.
If your assembly isnt very complex and you have just a few parts, export every single part as an .iges-file from your CAD. And then import the parts step by step. Dont import them all together. Sometimes this helps to avoid geometry problems generated due to import.
I suggest to import the parts as parts and not as regions, especially if you like to work with boolean oprerations after import.

After you have imported all your parts, you are able to check each part for geometry problems like free edges, non manifold vertices e.g.
To do this launch the surface repair tool and select the part you would like to check. Start the diagnostic just for free edges and non manifold edges and vertices. If the diagnostic find any issues you are able to fix them with the surface repair options. How this works is hard to explain in detail here in the thread, so just try. The main operations you will need is "delete faces", "create face by vertices", "fill holes" and "zip edges".
You will easily see how to use these operations after you have spend a short time for trying.

I hope i could help. Have fun :)

vinvalt December 29, 2011 04:37

non manifold error
 
i was working with a .stp format file. I exported this file in inventor in many other formats. .iges did not work but the parasolid formats .x_t and .x_b worked well:)

vinvalt January 2, 2012 06:20

system swap
 
I finished generating a surface mesh of 740 000 faces and now trying to generate the volume mesh. I started the process for 3 days now but it still not ended. What is surprising me is that although I have a physical memory of 8 GB, only 2.3 GB is being used and 3.3 GB of 10.2 GB for system swap is also being used with all 4 processors working at 100%.
I am thinking the use of the swap is what is delaying the process but I dont understand why the system still swap even though I still have a lot of physical memory which could be used instead. I dont also want to reduce the number of faces for my surface mesh since this might compromise the quality of my volume mesh and also the accuracy of my results.
can you please explain to me why this swapping and how to overcome this for improve upon the meshing process.
I use AMD Phenom(tm)II X4965 Processor.

abdul099 January 2, 2012 21:00

Do you try to mesh parallel? This could cause the process to hang. Better to do meshing in serial.
In most cases I had before, the volume cells to faces was about 10, therefore I would expect your mesh to have something roughly around 8 million faces (+- some millions). That shouldn't take more than one or two hours on your machine as long as it doesn't need to swap. When it needs to swap, it should be finished at least within a day, there can't be much memory missing. So you don't need to keep the process running for three days. When there's no change in the output window or the output file for more than two or three hours, I would just kill the job without getting a bad conscience.


All times are GMT -4. The time now is 18:37.