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-   -   How to get a CT scan from Mimics to Gambit (http://www.cfd-online.com/Forums/ansys-meshing/64251-how-get-ct-scan-mimics-gambit.html)

bigphil May 5, 2009 06:17

How to get a CT scan from Mimics to Gambit
 
Hi,

I am looking for some advice or tips.

I have CT scans of the pelvis, from which I can extract (using Mimics 10.01) the bones (femur & hip).

I want to mesh these objects in Gambit.

Does anybody know which format I should export the objects into Gambit? Or has anybody done this before and has advice?

Mimics can export in most of the main formats, but I am not sure which is the right one for me, so as I can create the best possible volume mesh in gambit.


Any advice or tips are much appreciated,

Philip.

:)

bigphil May 5, 2009 07:39

In the mimics help, there is a short section on "exporting to fluent". I followed this and can then export a '.msh' file of the femur leg bone.

When I import this into gambit, it is an enclosed surface. But I cannot convert this surface to a real volume, only to a virtual volume.

Then I cannot split this virtual volume up into hex meshable regions, because when I try split the volume with a plane or another volume, it says " cannot split because of associated non-real geometry".


Any help would really be appreciated,

Philip

bigphil May 7, 2009 11:44

Problem Solved... in a round-about-way
 
After quite a bit of work, and help from ansys support (which was extremely good :) ), a way around it has been found.

It takes quite a bit of work, but just for anyone who is interested:

Create polylines from the extracted geometry in Mimics, then export these as an IGES file.

Import this into Gambit, and merge all the edges. Then convert them all to real edges. Then export this file as an IGES.

Import this into Rhino. Then close all the curves, and create a tight loft surface from the lines. This surface can then be exported as a IGES back to Gambit, where it can be segmented into hex meshable regions and then hex meshed!

...phew

:)

If anybody has question, don't be afraid to ask.

As I said, thanks again to ansys support who sorted this out for me.

phanivasudev March 17, 2011 01:10

MIMICS output in Fluent
 
i have created a 3d model of heart but i'm being able to import it into fluent for hemodyamic analysis.. it says error reading file heart.msh.. please help!

bigphil March 23, 2011 04:47

Hi Phani,

I have no experience with Fluent (I am using OpenFOAM for my analyses).

Presumably Fluent is looking for heart.msh so make sure it is in the same directory as what ever mesh file you are trying to import. I would suggest opening a thread in the fluent section of this forum (http://www.cfd-online.com/Forums/fluent/) and there are lots of people with more experience there.

Philip

samkazmi April 10, 2012 05:13

mimics help needed
 
dear bigphill,

we have generated 3d model of nasal cavity on mimics and then we imported it on gambit. but there we could not define zones .. any idea? as fluent is failing to import the geometery.
we could send you our .dbs file if you ask us.
thanks

bigphil April 10, 2012 05:31

Quote:

Originally Posted by samkazmi (Post 353924)
dear bigphill,

we have generated 3d model of nasal cavity on mimics and then we imported it on gambit. but there we could not define zones .. any idea? as fluent is failing to import the geometery.
we could send you our .dbs file if you ask us.
thanks

Hi,

To specify zones in gambit, see here:
http://202.118.250.111:8080/fluent/G...guide/mg04.htm

Normally google is your friend if you want to do something with gambit.

Philip

kingjewel1 April 10, 2012 11:53

Just found this thread and Mimics looks like a quality piece of software. Thanks for the introduction! My question is whether you are still using GAMBIT because I'm looking for an equivalent free meshing tool to do similar sorts of analyses?:)

Regards,

bigphil April 10, 2012 12:15

Hi kingjewel1,

Mimics is a nice piece of software, however, I now use an open source software called 3DSlicer (http://www.slicer.org/). I find it very good for segmenting CT/MRI images.

For meshing, I mostly use ICEM CFD which I find to be better than Gambit especially from STLs from CT/MRI. Unfortunately I haven't found an open source software that does exactly what I want, but IA-FEMesh is OK for multi-block hex meshing STLs, and snappyHexMesh is good for STLs.

Philip

samkazmi April 10, 2012 16:33

Quote:

Originally Posted by bigphil (Post 353930)
Hi,

To specify zones in gambit, see here:
http://202.118.250.111:8080/fluent/G...guide/mg04.htm

Normally google is your friend if you want to do something with gambit.

Philip

hi philip,
thanks for replying.. but the problem is that when i import my geometry it shows one single surface. i want to know how to break one surface into more so that i can define my zones.for better understanding i can send you my geometry too if you want . kindly give me your mail address
once again thanks alot.

syed ali mesam (sam)

bigphil April 10, 2012 17:57

sam,

OK I think understand that you want to split up the surfaces into different boundary patches. Unfortunately as far as I have found it is quite difficult to do this in gambit (that's why I switched to ICEM).
As far as I remember, you have to cut the geometry with planes or other objects you have created. Also I think you have to cut everything as virtual geometry and possibly change one of the defaults.

Sorry I can't be of more help.

Philip


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