Nieminen Mika wrote:

/.../
>   Since many people have always worked with scanline-renderers and are very
> accustomed to them, they think that every renderer work the same way.
> 
>   In povray, and I think that in every raytracer, spheres are spheres, not
> polygon meshes. They are true mathematical, perfect spheres. And this applies
> to almost every primitive (except for primitives like bezier patch or
> heightfield).
>   CSG's are mathematically calculated, not approximated with polygons.
> 
> --
>                                                            - Warp. -

Correct me if I'm wrong, but is the fact that most POV primitives are
mathematical and 'perfect', an advantage - and yet a weakness?
As far as I know, things like non-linear transformations and true
displacement mapping require objects to be converted to triangles. These
things cannot be done in POV (except height_fields, which are true
displacements and consist of triangles).
I know that BMRT, a very good Renderman-compliant raytracer, can do true 
displacement mapping on objects - therefore albeit it is a raytracer, it
probably _does_  convert primitives into triangles for this purpose.

Margus

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