Dear Colleagues,

  I am planning to use povray to render a transparent object
which 
  may contain several thousands of round ended cylinders. I
noticed 
  that it is very slow and I am wondering if a change in the
way
  I generate the object might speed povray up. Since there
are no
  round ended cylinders as primitives in povray ( or at
least I am 
  not aware of their existence ) I create them by merging a
cylinder
  and two spheres. In order to render everything correctly I
have done 
  something like this:

  merge {
    merge {
      cylinder {}
      sphere {}
      sphere {}
    } // this is repeated a few thousand times
    ...
    scale <>
  }

  ( The reason why I have to use the first merge {}
statement
   is because these cylinders can overlap and this overlap
needs
    to be removed. ) 

  So I wonder if something like this is faster :

   #declare round_ended_cylinder = 
   merge { cylinder { <0,0,0>,<1,0,0>,1 }
            sphere {<0,0,0>,1}
            sphere {<1,0,0>,1}
   }

   merge {
      object {round_ended_cylinder 
              // here come a bunch of scaling, translation
and rotation 
              // statements to position the standard
cylinder properly in 
              // space by just giving the end points.
              // This is quite a lot of additional
computation 
      // repeat this a few thousand times
   }

   Before I recode my program I'd like to have some advice
...
   Any help is greatly appreciated. 

   Lothar Esser

------------------------------------------------------------------
Dr. Lothar Esser 
Howard Hughes Medical Institute 
5323 Harry Hines Blvd.
Dallas Texas 75235-9050
E-mail : ess### [at] chopswmededu
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