I'm creating a polygon object and getting a strange error on it.

polygon {
   5
   <.7,-1.1,.5>,
   <-.6,-1,.4>,
   <-.3,-1,-.4>,
   <-.4,-1.1,-.5>,
   <.7,-1.1,.5>
}

The file renders, but that poly doesn't show and I get the following 
error: "Parse Warning: Points in polygon are not co-planar. Ignoring 
plygons." Several other polys using some of the same points render just 
fine.

What am I doing wrong??

~Mike

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> What am I doing wrong??

Do all these points lie on the surface of *one* plane? I doubt it, just by
the look of the values spread around. If you use just three points, it
always works, as three points always create a plane, but a fourth one might
make some trouble. Maybe you've just had luck with the combination for other
polygons.

Regards,
Tim

-- 
"Tim Nikias v2.0"
Homepage: <http://www.nolights.de>

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Tim Nikias wrote:
>>What am I doing wrong??
> 
> 
> Do all these points lie on the surface of *one* plane? I doubt it, just by
> the look of the values spread around. If you use just three points, it
> always works, as three points always create a plane, but a fourth one might
> make some trouble. Maybe you've just had luck with the combination for other
> polygons.

A quick top-down view check reveals that you hit it spot on. I never 
would have even thought of checking that. And even once I knew that's 
what the problem was, it was trial-and-error to fix it!

Thanks a bunch!

~Mike

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In article <419e827f$1@news.povray.org>,
 Mike Thorn <mik### [at] realitycheckmultimediacom> wrote:

>>I'm creating a polygon object and getting a strange error on it.
>>
>>polygon {
>>   5
>>   <.7,-1.1,.5>,
>>   <-.6,-1,.4>,
>>   <-.3,-1,-.4>,
>>   <-.4,-1.1,-.5>,
>>   <.7,-1.1,.5>
>>}
>>
>>The file renders, but that poly doesn't show and I get the following 
>>error: "Parse Warning: Points in polygon are not co-planar. Ignoring 
>>plygons." Several other polys using some of the same points render just 
>>fine.
>>
>>What am I doing wrong??
>>
>>~Mike

  strange... points for polygon are defined with x and y coord. only !
  take a look at http://www.povray.org/documentation/view/3.6.1/294/
  and http://www.povray.org/documentation/view/3.6.1/69/

  klp

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kurtz le pirate wrote:..
> In article <419e827f$1@news.povray.org>,
>  Mike Thorn <mik### [at] realitycheckmultimediacom> wrote:
> 
> >>I'm creating a polygon object and getting a strange error on it.
> >>
> >>polygon {
> >>   5
> >>   <.7,-1.1,.5>,
> >>   <-.6,-1,.4>,
> >>   <-.3,-1,-.4>,
> >>   <-.4,-1.1,-.5>,
> >>   <.7,-1.1,.5>
> >>}
> >>
> >>The file renders, but that poly doesn't show and I get the following 
> >>error: "Parse Warning: Points in polygon are not co-planar. Ignoring 
> >>plygons." Several other polys using some of the same points render just 
> >>fine.
> >>
> >>What am I doing wrong??
> >>
> >>~Mike
> 
>   strange... points for polygon are defined with x and y coord. only !
>   take a look at http://www.povray.org/documentation/view/3.6.1/294/
>   and http://www.povray.org/documentation/view/3.6.1/69/
> 
>   klp
> 
From the documentation:

" All points of a polygon are three-dimensional vectors that have to lay 
on the same plane. If this is not the case an error occurs. It is common 
to use two-dimensional vectors to describe the polygon. POV-Ray assumes 
that the z value is zero in this case."

Nevertheless, I think you can use 3D coordinates to define the points. 
It's already a long time ago I met the same problems using the 
coordinates of the vertices for pentagons that are the faces of a 
dodecahedron. I remember it's a question of some "tolerance" Povray uses 
to see if the given points are coplanar. The method I prefered consisted 
in declaring a pentagon as the union of three triangles.
Some of the images can be seen on the pages devoted to polyhedra on my 
site.
Herman

-- 
home page: http://cage.ugent.be/~hs

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