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Import 3D from Catia

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Import 3D from Catia

Postby beber » Tue Feb 20, 2007 1:23 pm

Hi, I have tried to imported the Catia 3d model of a business jet but I do not know how to convert files. I can save as .IGS, .WRL, .DFX and other formats; I have tried with ac3d but it doesn t recognize my .WRL. I have tried with 3dMax, i converted from .IGS to .3DS.MAX but ac3d still do not accept this format even after renaming in .3ds. I have tried blender and other softs I do not know what to do now. What do you suggest? Is .AC the only format supported by FlightGear? Because on the How-to apparently with PLIB we can use many formats, but I do not know how to install Plib (I use windows xp). Please help me.
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Postby AndersG » Tue Feb 20, 2007 1:48 pm

If you can save as DXF blender can import that and export it as AC3D.
I use that route to convert my models made with BRL-CAD into AC3D format.
In blender (which I know very poorly) I just:
(i) select all and delete to get rid of the camera etc. (not sure if this is needed);
(ii) Choose file->import->dfx to load my DXF file;
(iii) Select all;
(iv) Choose file->export->ac3d to save it as ac3d.

I'm not sure the menu references are completely correct as I don't have blender on this computer.

/Anders
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Postby beber » Tue Feb 20, 2007 2:35 pm

Er, I just checked and I can't save as DXF with catia; I found the problem why ac3d does not accept the .WRL its because catia exports vrml2 and ac3d supports onl vrml1; i have looked for Vrml2>>Vrml1 converters but i did not find something simple. Anyone knows one? or any other solution?
Thanks
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Postby AndersG » Tue Feb 20, 2007 2:57 pm

It seems BRL-CAD might be able to import geometry from CATIA:
http://ftp.brlcad.org/VolumeIV-Converting_Geometry.pdf
(Search for CATIA)
So if you can install BRL-CAD and the import works then you can go on to AC3D via blender... There must be more convenient ways, though.

/Anders
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Postby beber » Tue Feb 20, 2007 3:35 pm

well i just installed BRL CAD but it seems difficult to use I do not know what to do to convert files there is no simple way? Thanks anyway :)
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Postby AndersG » Tue Feb 20, 2007 3:48 pm

Yes, BRL-CAD does have a a rather old school user interface. To import and export one actually has to run programs from the command line. (In your case: enf-g and g-dxf). If you are lucky the manual pages/online help works.
Try 'brlman enf-g' at the command prompt.

/Anders
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Postby beber » Tue Feb 20, 2007 3:59 pm

I have not found the commands, I just want to convert one file and this software is so complicated; you seem familiar with it, what should i type exactly in the command console to convert my catia file (.IGS) into .AC or other appropriate format? Thanks; by the way I still research a VRML2>>VRML1 converter (i have only found 1>>2 at the moment) anyone knows?
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Postby AndersG » Tue Feb 20, 2007 4:32 pm

Conversion using the defaults should hopefully be

> iges-g -o yourfile.g yourfile.iges
> g-dxf -o yourfile.dxf yourfile.g object_names

object_names needs to be the name(s) your object(s) got in the BRL-CAD database yourfile.g. The see the object names you can open the database in mged (the graphical editor in BRL-CAD) and give the command 'ls' (lists all objects) or 'tops' (lists the toplevel objects). The display an object in mged write 'e <object name>' and to remove it from the display 'd <object name>. Wildcards work in mged.

I'm not sure if object names are preserved in the iges -> g conversion and they do seem to often get truncated in the g -> dxf conversion.

If you have a sample .IGS file to send/publish I could try to convert it to see if the procedure works.

/Anders
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Postby beber » Tue Feb 20, 2007 8:27 pm

yes sure here is a link with the igs file: http://demo21.ovh.com/8b27cca0837a81fb3 ... aff9559cP/
I also tried with 3Dstudiomax8, I can open the IGS but with some bugs in the model, and when I want to save it as .3ds (to import it with ac3d or blender) it automatically acts as a word document and the sofwares don't want to open it. Anyway in the link I have put the 3 formats so if you can convert something that would be awesome. Thank you for you time.
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Postby Ampere » Wed Feb 21, 2007 3:09 am

Flightgear can accept .3ds files directly.
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"...and many others" doesn't cut it in my book.

Postby pauljs75 » Wed Feb 21, 2007 1:29 pm

It would be nice to know specifically which 3D mesh file formats are accepted. The generic "...and many others" as in the current documentation isn't really useful at all. :? I don't think many people want to go through a whole trial-and-error list of file formats to figure out what's actually covered by some catch-all. It should list only what is known to be currently supported and maybe hint if support is under development (and who's working on it) for other specific 3D formats.

At least the partial list mentioned is a good start, but they need to go and revise the rest to be something useful for potential contributors.

And since we're discussing file formats, what about .obj? That format seems to be quite popular in the graphics community and is well supported by modeling software (pretty much any program I can think of), is it covered in FG?
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Postby AndersG » Wed Feb 21, 2007 1:33 pm

beber wrote:yes sure here is a link with the igs file: http://demo21.ovh.com/8b27cca0837a81fb3 ... aff9559cP/
I also tried with 3Dstudiomax8, I can open the IGS but with some bugs in the model, and when I want to save it as .3ds (to import it with ac3d or blender) it automatically acts as a word document and the sofwares don't want to open it. Anyway in the link I have put the 3 formats so if you can convert something that would be awesome. Thank you for you time.


You are welcome. Unfortunately it seems the iges-g converter crashes when trying to convert the file so the route via BRL-CAD might be closed.

/Anders - out of ideas..
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Postby beber » Wed Feb 21, 2007 3:43 pm

Thank you for trying AndersG , I am a bit out of ideas too at the moment , the .3ds file exported from 3dstudiomax8 acts strange (some parts of the plane seems missing), could one of you try to load it in Flight Gear (it is available on http://demo21.ovh.com/8b27cca0837a81fb3 ... aff9559cP/ as the .igs and .wrl . The .wrl exported by catia is vrml2, and ac3d supports only vrml1 so I am still looking for a converter. Thank you for your help.
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Postby RatOmeter » Thu Mar 08, 2007 2:31 am

It would be nice to know specifically which 3D mesh file formats are accepted.


Likewise, but I'm beginning to suspect that .ac is the 3D format de jour. I've been having a devil of a time getting Paul's Bell 206 model in a usable format/condition. To be fair, a lot of the *devil* in that has been caused by my own ignorance, but I hope that is being corrected.

What I've seen:

3dconvert (a utility provided with FG from the plib folks, I think) seems to mangle 3D object names when converting from .obj to .ac and is therefore useless for that purpose.

Wings3D's orientation of the XYZ axes is, at least, a major irritation.

The preview feature of the FlightGear Launcher (fgrun) seems to have trouble properly displaying a model in any format other than .ac (I'm aware that fgrun is a different project). I'm sorry that I don't have specifics on hand to qualify that statement.

The above and my other novice experiences have led me to feel that the AC3D format is not just the most supported, but in a practical sense, the only supported format. Considering that FG is a F/OSS project, from whence comes the apparently narrow focus on a 3D format generated best by its parent, a commercial closed-source application?
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Postby Kugelfang » Fri Mar 09, 2007 12:54 am

Like you guys I found that *.ac seems to be the best supported model format. But I think this is mostly due to what plib supports, rather than what FG itself handles. I even found that though *.obj geometry showed correctly, I could never get the textures to show. Though that was several years ago. With the move to OSG, I'm not sure how much of this will remain relevant.

*.ac, I think, was incorporated when AC3D was still a small one man operation written in TCL. While never quite FOSS, it was much closer than its current incarnation. Over the years it has become more proprietary in nature.

--jeff
We were set in our ways. We believed in a good God, a bad Devil and a hot Hell, and more than anything else we believed that the same good God did not intend man should ever fly.
--Bill Tate (Crouch, The Bishop's Boys)
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