stbenge wrote:
> A fast-rendering solution to this would be to have a double_illuminate 
> or translucency pigment block, probably one for each texture and 
> inside_texture. Simply giving the leaf inside and outside textures will 
> not work as intended. Most programs have a translucency material layer, 
> and I think POV-Ray will have to have one of its own to match the 
> rendering capabilities of other programs.

A simple example of why something like this is needed would be paper 
currency. In any paper currency these days, there is a ghost image 
inside the paper. One side of the bill has one image, the other side 
another, and somewhere in the middle is the ghost image. Try to do this 
with POV. Chances are you'll end up resorting to using media or making a 
second object for the ghost.

Here's how it might look if you could specify a transluceny (aka 
density) pigment for surfaces:

object{
  fifty_dolla_bill // an infinitely thin rectangle
  texture{
   pigment{
    image_map{tga"presidents_mug.tga"}
   }
  }
  inside_texture{
   pigment{
    image_map{tga"capital.tga"}
   }
  }
  interior{
   translucency{
    image_map{tga"ghost_of_washington.tga"}
   }
  }
  double_illuminate
}

The ghost would only appear on the unlit side of the bill, where you 
could clearly see the effects of double_illuminate. A clever person 
could make ghost_of_washington.tga an average of the other two 
image_maps, to complete the effect.

I'm thinking it would be much simpler to have the effect specified in 
the interior block, as such a pigment would have to be common among the 
others.

Sam

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