david sharp wrote:
> 
> Nieminen Mika wrote:
> >   You can see from the image, that two of the normals are pointing to one
> > side of the triangle while the third is pointing to the other side. This may
> > be causing the problem. I think that all the normals have to be pointing to
> > the same side of the triangle.
> 
> This, in fact, seems to be, or was, the problem. That triangle was
> the only one,  of thousands, where the normals were reversed from
> one corner of the triangle to another, and it was the only triangle
> POV was not accepting. This is easy enough to detect and work around.
> 
> Thank you very much for your efforts and insights.
> 
> Now, my question is why does POV-Ray do that? What is wrong with
> one normal pointing 'up' while two point 'down' (or vice versa)?

  In effect you are twisting it into a fourth demension when you have
 two normals pointing in the opposite direction of each other on one
 object.

-- 
Ken Tyler

mailto://tylereng@pacbell.net

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