I can't do bounded_by on prism somewhy, but its not a mathematical
shape,
so on what bounded_by do applys on?

conic_sweep prism is ending at a point, that is 1 * delta_height (end
height - start height)
the angle is not neccesarily 45, but it acts funny on advanced prisms
like this:

prism {
  conic_sweep
  linear_spline
  -1,        // height 1
   0,        // height 2
  10,          // number of points
  < 0.2, -1.0>, < 0.2,  0.2>, < 1.0, -0.2>, < 1.0,  0.2>, < 0.2,  1.0>,
  <-0.2,  1.0>, <-1.0,  0.2>, <-1.0, -0.2>, <-0.2,  0.2>, <-0.2, -1.0>
  pigment {color rgb 1}
  // [open]
  // [sturm]
}

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What exactly is the problem? I can't see anything wrong with bounded_by.
BTW, I do remember one thing about conic prisms; the point is always at y=0
and the width is "normal" at y=1 or y=-1, regardless of the start and end y
values. This threw me off because at values like y=4 I was getting huge
prisms and didn't know why.

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In article <38C651F0.B6EB3B74@netvision.net.il>, Eitan Tal 
<eit### [at] netvisionnetil> wrote:

> I can't do bounded_by on prism somewhy, but its not a mathematical 
> shape, so on what bounded_by do applys on?

I don't really understand the problem you are having, but the fact that 
you are still messing around with bounded_by seems to imply that you are 
still trying to misuse it as a kind of clipped_by. The bounded_by 
feature is NOT a CSG operation. It does not operate at all like one. It 
does not chop pieces of the object off. It is an optimization feature, 
and one which you usually don't have to bother with at all because of 
the automatic bounding done by the program. All shapes use bounded_by, 
including solid shapes like spheres, cones, lathes, and prisms, and 
non-solid shapes like polygons, meshes, and bezier patches.

If you want to chop pieces off of the object, use clipped_by(to leave 
the cut surfaces open), or intersection(to close the cut surfaces). The 
manual and example scenes have several samples and explanations of these.

If this is not the problem you are having, you will have to explain it 
more clearly and include code demonstrating your problem. The code you 
enclosed didn't even include a bounded_by statement.

-- 
Chris Huff
e-mail: chr### [at] yahoocom
Web page: http://chrishuff.dhs.org/

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