Why does the following code generate a:
Warning: Unnecessary bounding object removed.
for each tile in the road?  (POV-Ray 3.5 beta 6)

Thanks,
Hershel

Code:

#declare TileSize = 8;
#declare I = -30;
#declare Road =
union {
   #while (I<=400)
      #declare J = -50;
      #while (J<=50)
         plane { y, -20
            bounded_by { box { <J,-30,I>, <J+TileSize,0,I+TileSize> } }
            clipped_by { bounded_by }
         }
         plane { y, -20
            bounded_by { box { <J+TileSize,-30,I+TileSize>,
<J+TileSize*2,0,I+TileSize*2> } }
            clipped_by { bounded_by }
         }
         #declare J=J+TileSize*2;
      #end
      #declare I=I+TileSize*2;
   #end
   texture {
      pigment {
         granite
         scale <0.3, 1, 0.3>
         colour_map {
            [0 1 colour Black
                 colour red 0.5 green 0.5 blue 0.5]
         }
      }
      finish {
         specular 1
         roughness 0.02
         reflection 0.25
      }
   } // texture
   no_shadow
}

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Hershel Robinson wrote:

> Why does the following code generate a:
> Warning: Unnecessary bounding object removed.
> for each tile in the road?  (POV-Ray 3.5 beta 6)
> 
It seems that it would render faster without the manual bounding. If you do 
not want that povray removes your bounding object, then use the '-UR' 
switch. This will also remove the warnings.

- Micha

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Why are you using clipped planes instead of simpler boxes?

--
Jonathan.

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> It seems that it would render faster without the manual bounding. If you
do
> not want that povray removes your bounding object, then use the '-UR'
> switch. This will also remove the warnings.

You are correct--55 seconds with bounding and 41 without bounding, i.e. I
removed the bounded_by statements myself.  Do you know why it's faster
without them?

>Why are you using clipped planes instead of simpler boxes?

Well, this 'road' used to be a tiled floor in a room.  As the scene
progressed, I removed the walls and wanted to make half the tiles clear.
The clipped planes was just the first idea which came to mind--it's sort of
the evolution of the floor-plane.

Thanks for responding,
Hershel

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Wasn't it Hershel Robinson who wrote:
>Why does the following code generate a:
>Warning: Unnecessary bounding object removed.
>for each tile in the road?  (POV-Ray 3.5 beta 6)
>
>Thanks,
>Hershel

Because the bounded_by's are unnecessary. The scene renders faster if
you replace

            bounded_by { box { <J,-30,I>, <J+TileSize,0,I+TileSize> } }
            clipped_by { bounded_by }

by
            clipped_by { box { <J,-30,I>, <J+TileSize,0,I+TileSize> } }


and replace

            bounded_by { box { <J+TileSize,-30,I+TileSize>,
<J+TileSize*2,0,I+TileSize*2> } }
            clipped_by { bounded_by }

by

            clipped_by { box { <J+TileSize,-30,I+TileSize>,
<J+TileSize*2,0,I+TileSize*2> } }

I.e. get rid of the bounds and just clip.

-- 
Mike Williams
Gentleman of Leisure

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Hershel Robinson wrote:

>> It seems that it would render faster without the manual bounding. If you
> do
>> not want that povray removes your bounding object, then use the '-UR'
>> switch. This will also remove the warnings.
> 
> You are correct--55 seconds with bounding and 41 without bounding, i.e. I
> removed the bounded_by statements myself.  Do you know why it's faster
> without them?
> 

POV-Ray does bound the object itself and often it does it quite well. Your 
bounding has not been good as you bounded every plane itself. The warning 
pov has given was because with that kind of CSG you were using the 
automatic bounding is generally better than manual bounding. This has not 
to be true in every case though.

- Micha

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