In article <38B82920.4AF0416A@netvision.net.il> , Eitan Tal 
<eit### [at] netvisionnetil>  wrote:

> There are only 2d polygons in povray, why don't they have any 3d
> polygons?
> it can be done very easily with mesh.
>
> I am just asking why nobody tried to make a small inc file that will do
> that.
> is it impossible somewhy? a bug? because I'd like to try to do a one,
> that should not be too hard
>

Not impossible, but a polygon is not clearly defined if it is not planar.
You can verify this easily with a piece of paper (US Letter size or A4 work
well) which is a four edge polygon.  Hold it on the diagonal edges. If you
pull carefully would will see that the other two edges fall downward. Now
push instead. The edges still fall downward but the shape changes.
Now imagine four points defining the edges. No matter what you do, you can
still construct the mesh in two ways - which one is correct?  None, there is
no rule that can help you.
As you see, the surface of a polygon is not clearly defined, there are
several correct solutions (the more points the more answers).


       Thorsten

Post a reply to this message