It actually can be easily solved, but still is problamatic, i'll detail:
i was talking about a 12 facet polyhedra ( may an octahedron???)
any way i have 12 symetric planes for which i need to find an object which
consists of all the points that lay inside any 11 of the 12 planes, so
orginally th problem was solved by:
union {
intersect(a1.....a11)
intersect(a1.......a10,a12)
etc.....
intersect(a2.............a12)
}
but i simplyfied it to :
union {
    intersect ( 5 specific planes); #1
    intersect ( 5 other specific planes); #2
    etc...
    intersect ( 5 other specific planes); #11
    intersect ( 5 other specific planes);#12
}
it still is ugly, since i only have 12 planes, redifining each one 5 times
is heavy on the parser and the renderer, the point is pov-ray does not
include complex-csg objects, problems more complex than mine are not
solvable in such a simple way, 9 out of 12 planes would be very big (9 over
12 = 220 objects).
Coding such a csg object is not much diiferent than an intersection or a
union.
about the macro, it just makes the code look better, the parser still does
the same work...
any way, thank you for your reply..
feel free to reply furthur more
 Oded

Tor Olav Kristensen <tto### [at] onlineno> wrote in message
news:39593007.12993FFB@online.no...
>
> Tor Olav Kristensen wrote:
>
> > Oded wrote:
> > > ...
> > > what i needed to do for that was to define a union of 12 intersections
of 6
> > > objects which was was quite dirty (mathematically speaking)
> > ...
> > And don't you mean union of 15 intersections of 6 objects ?
> > ...
>
> I forgot that there are many ways to combine (or permutate ?)
> 6 objects.
>
> Here's another one:
>
> 3 & 4 & 5 & 6
> 2 & 4 & 5 & 6
> 2 & 3 & 5 & 6
> 2 & 3 & 4 & 6
> 2 & 3 & 4 & 5
> 1 & 4 & 5 & 6
> 1 & 3 & 5 & 6
> 1 & 3 & 4 & 6
> 1 & 3 & 4 & 5
> 1 & 2 & 5 & 6
> 1 & 2 & 4 & 6
> 1 & 2 & 4 & 5
> 1 & 2 & 3 & 6
> 1 & 2 & 3 & 5
> 1 & 2 & 3 & 4
>
> How are your combinations for the intersections ?
>
> Anyway I have a feeling that your problem (even
> if I don't understand what it is :-) could easily be
> solved by a macro with some loops that does
> all the CSG.
>
>
> Tor Olav
> --
> mailto:tor### [at] hotmailcom
> http://www.crosswinds.net/~tok/tokrays.html
>
>

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