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-   -   [DesignModeler] Bug in DM (http://www.cfd-online.com/Forums/ansys-meshing/109029-bug-dm.html)

Far November 7, 2012 12:04

Bug in DM
 
I am working on some youtube tutorials where I want to make the Hexa meshing in ICEM on the gambit meshing tutorial (know as sedan tutorial). I wanted to make the some repairing work in DM on sedan , but I am surprised to see that DM is making more issues, whereas Gambit is perfect. I have also tried in ICEM with no errors.

Any one knows what is the problem with DM?

Gambit:
http://imageshack.us/a/img31/2301/gambitj.png


Design Modeller:
http://imageshack.us/a/img841/9301/94666674.png


ICEM:
http://imageshack.us/a/img833/9484/icem.png

diamondx November 7, 2012 12:06

can you share file ??
let's investigate this together...

Far November 7, 2012 12:09

Here you go ;)

https://dl.dropbox.com/u/68746918/sedan.igs

See this thread and post #12 (same case in ICEM : tetra + prism)
http://www.cfd-online.com/Forums/ans...d-pl-help.html

diamondx November 7, 2012 13:56

did you try other format, personnaly don't like iges....

diamondx November 7, 2012 14:01

OK, may be i have a clue.
The default import option in designmodeler includes "stitch surface" as yes
Switching it to no resolves the problem.
https://dl.dropbox.com/u/35161486/sedan.png

that is may be due to designmodeler trying to stitch a complex set of surfaces...

Far November 7, 2012 14:22

that is the problem. you are good at DM

Far November 7, 2012 14:24

are you able to repair the dirty geometry in DM? Or we should use the spaceclaim?

diamondx November 7, 2012 14:27

i always use DM, i never used spaceclaim...

Far November 7, 2012 14:28

I mean, can you repair the missing surfaces, sliver faces, short edge and other problems in sedan cad model (I just shared on forum) in DM.

I see more problems as compared to gambit and ICEM in DM

diamondx November 7, 2012 14:30

not sure but let's do this... :D

diamondx November 7, 2012 15:41

ok, this is what i've done so far:
i removed some very bad surfaces that were merged to the ones next to them

https://dl.dropbox.com/u/35161486/step1.png

i recreated them using edges:
https://dl.dropbox.com/u/35161486/step2.png

I did a "sew" with a very small tolerance (10e-6 if project was imported in meter)

https://dl.dropbox.com/u/35161486/step3.png

https://dl.dropbox.com/u/35161486/step4.png

Did the same for the back, noticed that surface is not really what i want, but i think that can i be solved if i used a split and did it in two step instead of one:
https://dl.dropbox.com/u/35161486/step5.png

Last surfce is created so i can perform a fill... of course sew has to be done in each steps

https://dl.dropbox.com/u/35161486/step6.png

there may be a easier way of doing this... hope i can discover it in the future when dealing with other geometries

diamondx November 7, 2012 16:32

i did the split i mentioned for the back, created three surfaces seperatly then sew:

https://dl.dropbox.com/u/35161486/step7.png

Geometry is repaired:

https://dl.dropbox.com/u/35161486/step8.png

Far November 7, 2012 16:51

Questions
 
Two questions come into mind:

1. Why in first palce DM had the errors, when gambit and ICEM didn't

2. After repairing are you sure that they are original surfaces?

diamondx November 7, 2012 16:57

i don't know how gambit works... because your iges contains surfaces, and since icem cfd is a surface based mesher, it didn't find any difficulty dealing with. DM includes solid and surface, you gave it a hard time maybe ?!
After repairing , the original surfaces are merged and sewed into a new one.
sorry for not being clear here it's first and only things it came to my mind

Far November 7, 2012 16:59

Gambit is solid direct modeller and works on solid as DM. And that IGES was a solid model and ICEM converted it into surfaces by default.

If that model was not solid then DM would have the surfaces only.

diamondx November 7, 2012 17:01

sorry, my knowledge is limited :o

diamondx November 7, 2012 17:15

that being said, how about the step file ??

Far November 7, 2012 17:19

Quote:

Originally Posted by diamondx (Post 390886)
that being said, how about the step file ??

Gambit only provided the IGES file :mad:, but may be I can export that file in step format form gambit and then we try in DM? What do you say?

diamondx November 7, 2012 17:23

export step from icem and it will work on DM...


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