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-   -   Splitting Volumes with Faces in Gambit (https://www.cfd-online.com/Forums/fluent/29494-splitting-volumes-faces-gambit.html)

 An Modh Coinniolach March 13, 2002 11:27

Splitting Volumes with Faces in Gambit

I need to split the volume around a blade with faces wrapped around said blade. I create the geometry (the solid and the faces)in Pro/E and import them into Gambit as STEP files.

Having brought the faces in, I heal them and them try to split the volume using these faces (the faces extend a short distance further than the solid geometry, giving me a total cut through the domain). I need to end up with two real, connected volumes.

Now, most times that I try this, the whole thing fails. The first three faces split satisfactorily (there are four altogether, upper surface, lower surface and the leading and trailing edges). The problem arises when I try to split the volume with the final face. I get an error saying that the Cellular Topology structure is corrupt and that the geometric model is corrupt.

Generally I persevere and eventually I get it to work, but I spend a lot of time just stuck at this point and that is very unsatisfactory.

Could anyone shed light on this problem, suggest any tricks that might alleviate my situation? It would be of enormous assistance to me.

 Phil March 13, 2002 12:08

Re: Splitting Volumes with Faces in Gambit

I can't help your problem but am experiencing a similar problem as you, why do you import as step and not use the direct proE import? Is the the STEP geometry generally more robust?

 An Modh Coinniolach March 13, 2002 12:33

Re: Splitting Volumes with Faces in Gambit

The main motivation behind me not using the direct Pro/E import is that you need to specify a start up command in Gambit for Pro/E and I have never bothered finding out how to do it because it is handier to just get Pro/E to spit out a STEP file and import that into Gambit. Actually it is possible that my release of Gambit cannot run Pro/E in the background anyway (Gambit 1.3 on Windows NT). As regards robustness, I have found that the STEP file import is ranked second in terms of ways to get geometry out of Pro/E and into Gambit. The full list being:

1. PROSAT Translator 2. STEP 3. Spatial IGES and Healer 4. Native IGES 5. Mesh 6. Optegra Visualizer 7. Direct (VRML) 8. STL

The "direct import" option is ranked seventh. You could export the file from Pro/E as vrml and use somthing like

import vrml "model.wrl"

to import this into Gambit. You will end up with non-conformal faceted geometry in Gambit. I'm not sure what that means, but I don't like the sound of it one little bit.

So for these reasons and more, STEP seems to be the best bet for Pro/E into Gambit.

All that and I still can't get this thing to split reliably.

So in short, "yes"!

 yangqing March 13, 2002 20:54

Re: Splitting Volumes with Faces in Gambit

i had face this problem recently. but i create it in gambit, and the result is good. split option should be: volume "split with face" face(real) "connected" maybe it will be helpful for your case

 An Modh Coinniolach March 14, 2002 07:57

Re: Splitting Volumes with Faces in Gambit

That is precisely what I am doing (split with face, real connected).

Ages ago I was doing something where I would import the faces and then delete the faces (keeping the lower geometry). Then I would populate some of the remaining edges with vertices and then delete those edges, put splines through the vertices, getting my geometry back and then create faces by extruding my spline curves to regenerate my faces.

That did not work particularly well either.

I have been around the block with this and then some.

 Sundar March 14, 2002 14:19

Re: Splitting Volumes with Faces in Gambit

Hi Conniolach, I am relatively new to this Pro-E Gambit Translator, but I would like to get more info on it. Till now I build my geometries in gambit and never had an issue. Becos of the integration with design team we will be importing Pro-e Geomtries, so It could be very helpfull if you can give me a bunch of check list, what to do and what not to do on Pro-e Gambit translator. Thanks Sundar

 An Modh Coinniolach March 15, 2002 06:02

Re: Splitting Volumes with Faces in Gambit

Hello Sundar.

As you will have read, I import my geometry from Pro/E using and intermediate file (STEP format). I have never used (and probably can't given my configuration Gambit 1.3 under WinNT) the direct Gambit/Pro/E interface.

Since you asked, I have just tried importing geometry using a VRML intermediate file. This is a manual version of the direct import option. The volume came in satisfactorily, the faces came in as virtual geometry. I then tried to import a step file containing faces but I got an error saying "ACIS error 2302 : no current bulletin board exists". Interesting.

In terms of "dos and don'ts", there is very little advice to give. Importing the STEP file produced by Pro/E (the later versions do this, I am running Pro/E 2001) is uneventful. If there were any advice I could give, it would be to do as little in Gambit as possible in terms of preparing the geometry, but you have been creating your geometry in Gambit up until now so I guess you will have no problem.

You should have no problem getting your Pro/E geometry into Gambit, using STEP files is very reliable and easy.

 goyalnn May 2, 2011 22:27

hi

I have created a person (made of different volumes) in GAMBIT. The person is standing inside a big cube which in itself is a separate volume. I want to study the air flow inside the cube. Do I have to first split/subract or do anything like that with outside volume and the volumes inside it (person) or Can I just go ahead and create edge,face and then volume mesh for the whole thing without specifying any such relation between them?? someone told me it is necessary to split but when Im trying to split the person from the outside volume, it gives me an error "coincident face_face_ints with different body vertices". Can anyone help me??
I would greatly appreciate your response.

Thanks!

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