In article <web.3f4d28bf8f004971d63a77300@news.povray.org> , 
"gramirosimancas" <nomail@nomail> wrote:

> I think you are wrong.
>
> In the 2d case where "pyramid raytracing" is used successfully in many
> vector drawing programs and render libs there is an alias removal bost
> while compared to bad libraries that do simple pixel sampling (equivalent
> to 3d raytracing).
> An example library that does this kind of antialiasing in the 2d world is
> http://www.levien.com/libart/

Intersections in two dimensional are relatively easy for the "average" type
of object.  However, even for two dimensional geometry, in particular
certain functions, you cannot exactly determine the area even for tiny
subsections.

As far as the three dimensional case is concerned, the equations to
determine the surface area of many of the primitives supported by POV-Ray
are, well, mathematically not even solvable at all.  The isosurface object
is ideal to create such functions, but the problem is not limited to this
object type.  If you don't believe me, just consider looking into the "tube"
created by one of those functions (from your average math book) that has an
infinite surface area.  Now imagine your pyramid is exactly on the tube's
axis...

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

Post a reply to this message