scott <sco### [at] scottcom> wrote:
> >  Their problem is that automatically creating rounded corners for any
> > given object:
> >
> > 1) is impossible in the general case,
> > 2) in many cases where it's possible it results in extremely slow renders,

> Those first two are not really problems though - ie we shouldn't say not to 
> include a feature because it won't work with all possible objects and might 
> result in extremely slow renders sometimes.

  However, what those two things do tell us is that the problem is very hard.
In other words, it's very hard to come up with a good implementation (even
if we completely disregard rendering speed) which will work well and look
good (eg. doesn't suffer from visual artifacts).

> > 3) would require tesselating the object and rendering the resulting mesh
> >   (with the corner modifications).

> That's not the only way to do it.

  But it's the best alternative. After tesselation you can do almost anything
you want with the objects with little limitations. The only hard step in this
process is the tesselation itself.

> >  POV-Ray, however, handles mathematical primitives (such as boxes and
> > planes) and their CSG. Rounding their corners is a problem which is
> > several orders of magnitude harder.

> But not impossible, look at any CAD software that manages it with 
> mathematically defined CSG.

  CAD software always tesselate their geometry before rendering. They do not
render untesselated mathematical surfaces.

-- 
                                                          - Warp

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