John M. Dlugosz wrote:
> 
> Ken wrote in message <36E34714.CA08E2BC@pacbell.net>...
> > DXf has the ability to store either face or line info or both. Sometimes
> >the program exporting the model will only export one or the other sometimes
> >both. Conversion programs also have their own way to handle the data in the
> >dxf file and it varies with who wrote it.
> 
> But does the face info include normals?  That is, is one "face" a plain
> triangle (three points) or a smooth triangle (three points and three
> normals, as in POV and OpenGL)?  For that matter, how do mesh-based editing
> programs define such things?  I see a mesh of triangles, but how does it
> know those approximate real surfaces?  Or are they just facets, period, and
> it uses the joining angle idea like the import setting you told me about, to
> smooth things implicitly (which would make it difficult to represent a sharp
> edge that is below the critical angle!)
> 
> 'learning,
> --John

  It does not store surface normal informations that I'm aware of.
It is just face information. As you say the conversion program will
evaluate each junction and if it falls within the defined angle it
becomes acted upon. There are times that a large specified smoothing
angle will take out every sharp edge on a model. That's where trial
and error come into play I'm afraid. I believe 3DWin has a default
smoothing angle of 70, unless you change it from the shipped setting
and it provides a good general purpose smoothing amount.
  You can immediatly see when smoothng is turned off on models that
have a low face count and it's pretty amazing what a large angle can
do to correct it. I think the use of the smooth triangle function needs
to be evaluated on a per model basis as it can add in both parsing time
and quite considerably in the file size produced.

-- 
Ken Tyler

mailto://tylereng@pacbell.net

Post a reply to this message

DXF doesn't include smoothing info. Converters like 3DWin can let you specify
an arbitrary smoothing threshold, but the smoothing is then done based on the
shape of the mesh; it is in no way specified in the DXF file. The 3DS format
has special "smoothing groups" which let you specify different smoothing
thresholds for different parts of the mesh, but I know of no converters that
can produce plain/smooth POV triangles based on this.
If you want all triangles to be smooth, specify a smoothing angle of 180
degrees in 3DWin. If you want a sharp edge above the smoothing threshold,
you're in trouble :)

Margus

John M. Dlugosz wrote:
> 
> But does the face info include normals?  That is, is one "face" a plain
> triangle (three points) or a smooth triangle (three points and three
> normals, as in POV and OpenGL)?  For that matter, how do mesh-based editing
> programs define such things?  I see a mesh of triangles, but how does it
> know those approximate real surfaces?  Or are they just facets, period, and
> it uses the joining angle idea like the import setting you told me about, to
> smooth things implicitly (which would make it difficult to represent a sharp
> edge that is below the critical angle!)
> 
> 'learning,
> --John

Post a reply to this message

On Sun, 07 Mar 1999 17:20:14 -0600, Thorsten Froehlich 
	<fro### [at] charliecnsiitedu> wrote:
>In article <36e3010b.0@news.povray.org> , "John M. Dlugosz" 
><joh### [at] dlugoszcom> wrote:
>
>> Well, 3DWin didn't work.  It output plain, not smooth, triangles, and the
>> resulting .inc file couldn't be read by POV 3.1 "Superpatch" anyway!
>
>So then why doin't you simply use the official 3.1 version? :-)

and/or submitted a bug report to the superpatch maintainer?  :)

Post a reply to this message

On Sun, 7 Mar 1999 20:47:52 -0600, John M. Dlugosz <joh### [at] dlugoszcom> wrote:
>I'm finding this very interesting.  So what's the best way to go from Poser
>3 to POV?
>I don't know how Mick created this DXF file, but once I know better, 3-D
>meshes I create myself can be set up better.  To this end, any advise is
>much appreciated.

I have a Perl script that will convert Poser-exported RIB files to POV
.inc files with smooth triangles.  If you email me at par### [at] mailfwicom
I'll send you a version that's purported to work with Poser 3, though I
haven't been able to test it myself and I'm not sure it didn't change the
semantics of the old script in ways I don't like very much.  For older 
versions of Poser, the script at http://www2.fwi.com/~parkerr/traces.html 
will do the trick.

Post a reply to this message

Ron Parker wrote:
> 
> On Sun, 07 Mar 1999 17:20:14 -0600, Thorsten Froehlich
>         <fro### [at] charliecnsiitedu> wrote:
> >In article <36e3010b.0@news.povray.org> , "John M. Dlugosz"
> ><joh### [at] dlugoszcom> wrote:
> >
> >> Well, 3DWin didn't work.  It output plain, not smooth, triangles, and the
> >> resulting .inc file couldn't be read by POV 3.1 "Superpatch" anyway!
> >
> >So then why doin't you simply use the official 3.1 version? :-)
> 
> and/or submitted a bug report to the superpatch maintainer?  :)

It's not a bug with the superpatch. For some reason 3DWin is not
reading the file correctly and is producing a mesh composed of
100% degenerate triangles. When Pov parses the scene it disallows
every degenerate triangle then issues a warning that there are no
triangles in the mesh. First time I have ever seen a conversion
program write a file with all degenerate triangles before.

Weird comes to mind.

-- 
Ken Tyler

mailto://tylereng@pacbell.net

Post a reply to this message

On Mon, 08 Mar 1999 05:51:23 -0800, Ken <tyl### [at] pacbellnet> wrote:
>Ron Parker wrote:
>> 
>> On Sun, 07 Mar 1999 17:20:14 -0600, Thorsten Froehlich
>>         <fro### [at] charliecnsiitedu> wrote:
>> >In article <36e3010b.0@news.povray.org> , "John M. Dlugosz"
>> ><joh### [at] dlugoszcom> wrote:
>> >
>> >> Well, 3DWin didn't work.  It output plain, not smooth, triangles, and the
>> >> resulting .inc file couldn't be read by POV 3.1 "Superpatch" anyway!
>> >
>> >So then why doin't you simply use the official 3.1 version? :-)
>> 
>> and/or submitted a bug report to the superpatch maintainer?  :)
>
>It's not a bug with the superpatch.

I didn't expect that it was, but if using the official version as
Thorsten suggested had worked, I would have expected a bug report.
I'm pretty sure the current superpatch doesn't make any changes to
the mesh parser anyway, so I'd be really surprised by a bug there.

Post a reply to this message

par### [at] my-dejanewscom (Ron Parker) writes:

> On Sun, 07 Mar 1999 17:20:14 -0600, Thorsten Froehlich 
> 	<fro### [at] charliecnsiitedu> wrote:
> >In article <36e3010b.0@news.povray.org> , "John M. Dlugosz" 
> ><joh### [at] dlugoszcom> wrote:
> >
> >> Well, 3DWin didn't work.  It output plain, not smooth, triangles, and the
> >> resulting .inc file couldn't be read by POV 3.1 "Superpatch" anyway!
> >
> >So then why doin't you simply use the official 3.1 version? :-)
> 
> and/or submitted a bug report to the superpatch maintainer?  :)

Did you get my personal mail about the compiler warnings? I've send it to 
your account at dejanews, but I've never got any response.

Thomas

-- 
http://www.fmi.uni-konstanz.de/~willhalm

Post a reply to this message

On 08 Mar 1999 16:08:07 +0100, Thomas Willhalm 
	<Tho### [at] uni-konstanzde> wrote:
>par### [at] my-dejanewscom (Ron Parker) writes:
>
>> On Sun, 07 Mar 1999 17:20:14 -0600, Thorsten Froehlich 
>> 	<fro### [at] charliecnsiitedu> wrote:
>> >In article <36e3010b.0@news.povray.org> , "John M. Dlugosz" 
>> ><joh### [at] dlugoszcom> wrote:
>> >
>> >> Well, 3DWin didn't work.  It output plain, not smooth, triangles, and the
>> >> resulting .inc file couldn't be read by POV 3.1 "Superpatch" anyway!
>> >
>> >So then why doin't you simply use the official 3.1 version? :-)
>> 
>> and/or submitted a bug report to the superpatch maintainer?  :)
>
>Did you get my personal mail about the compiler warnings? I've send it to 
>your account at dejanews, but I've never got any response.

I think I have it stashed away somewhere.  I haven't done anything with
it yet, but I expect to find some time to do some more real work soon.  I
have my own Linux installation and my own copy of egcs now, so hopefully
I can reproduce most of them myself.  It's not that I've forgotten you,
just that I haven't had much time to do much with it of late.  Sorry I 
didn't write back to you to tell you this; I honestly thought I had.  I
really don't like the way dejanews handles email...

Post a reply to this message

Likewise.  But I mentioned this little detail (which version I was running)
just to be on the safe side.

--John

Ron Parker wrote in message <36e3d95d.0@news.povray.org>...
>On Mon, 08 Mar 1999 05:51:23 -0800, Ken <tyl### [at] pacbellnet> wrote:
>>Ron Parker wrote:
>>>
>>> On Sun, 07 Mar 1999 17:20:14 -0600, Thorsten Froehlich
>>>         <fro### [at] charliecnsiitedu> wrote:
>>> >In article <36e3010b.0@news.povray.org> , "John M. Dlugosz"
>>> ><joh### [at] dlugoszcom> wrote:
>>> >
>>> >> Well, 3DWin didn't work.  It output plain, not smooth, triangles, and
the
>>> >> resulting .inc file couldn't be read by POV 3.1 "Superpatch" anyway!
>>> >
>>> >So then why doin't you simply use the official 3.1 version? :-)
>>>
>>> and/or submitted a bug report to the superpatch maintainer?  :)
>>
>>It's not a bug with the superpatch.
>
>I didn't expect that it was, but if using the official version as
>Thorsten suggested had worked, I would have expected a bug report.
>I'm pretty sure the current superpatch doesn't make any changes to
>the mesh parser anyway, so I'd be really surprised by a bug there.

Post a reply to this message