[Radiance-general] Re: obj2rad failing

[Erwin Zierler]

Hi Greg,

thanks for the investigation. This means that Archicad produces faulty OBJ files or something went wrong during the export. I will have to ask the folks who gave me the file. I tried importing this file into other modellers, some of them seem to ignore all faulty objects, and some of them import everything only up to that line. But I have not checked this out in great detail. Maybe I can implement some kind of syntax checker that does some sanity checks on obj files before I throw them at obj2rad. I guess my goal will be to import at least the geometry, even if the vn or vt info is not correct. 
Regards,
 Erwin


-------- Original Message --------
Subject: [Radiance-general] Re: obj2rad failing (08-Okt-2008 7:21)
From:    Greg Ward <gregoryjward at gmail.com>
To:      radiance at rendigo.com

> Hi Erwin,
> 
> The problem with that face is that it refers to vertex normals 29760,  
> 29761, and 29763, whereas you've only defined 544 normals up until  
> that point in the file.  It is illegal to refer to an undefined index  
> in obj2rad, hence the reported error.  None of the other OBJ file  
> converters will like it, either.  The faces up until that point in  
> the file don't use vertex normals, so they pass without complaint.
> 
> -Greg
> 
> P.S.  To those of you confused by this exchange, Erwin sent me his  
> OBJ file in a separate e-mail at my request.
> 
> > From: "Erwin Zierler" <radiance at rendigo.com>
> > Date: October 7, 2008 3:19:01 PM PDT
> >
> > Hi all,
> >
> > I am currently testing differrent converters with what you could  
> > call 'real-world' scene files originating from differrent CAD  
> > systems and modellers. While exploring the capabilities of obj2rad  
> > I noticed that it fails on a OBJ File (exported from ArchiCAD) with  
> > the following error:
> >
> > example.obj: Wavefront syntax error near line 167037: Bad face
> >
> > Here is the 'bad' part of the file (line 167037 - 167041)
> >
> > f  29760/83929/29760 29761/83930/29761 29762/83931/29762  
> > 29763/83932/29763
> > vt 42.5353 8.46865
> > vt 42.5353 8.474
> > vt 42.53 8.474
> > vt 42.53 8.469
> >
> > Other parts of the obj file work fine:
> >
> > f  29682/83789 29683/83790 29684/83791 29685/83792
> > vt -0.019984 -0.400179
> > vt 8.56333 -0.400179
> > vt 8.58332 0
> > vt 0 0
> >
> > The OBJ file format specification tells me that both 'f' lines are  
> > perfectly legal:
> >
> > Using v, vt, and vn to represent geometric vertices, texture vertices,
> > and vertex normals, the statement would read:
> >
> >     f v/vt/vn v/vt/vn v/vt/vn v/vt/vn
> >
> > But obj2rad doesn't seem to like the 3rd number(s) vn which are  
> > supposed to represent the vertex normals. The obj2rad man page  
> > doesn't go into much detail about the 'f' statement with respect to  
> > allowed format. Running obj2rad -f (ignoring vertex normal  
> > information) also fails on the exact same line.
> >
> > I will try to get ahold of some smaller ArchiCAD OBJ exports now  
> > and see if I can narrow down the problem. If anyone has some ideas  
> > or similar experiences I would sure appreciate to hear from you!
> > TIA,
> >  Erwin
> 
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