Ignore the previous post if it didn't get cancelled (I posted the PNGs not
the JPGs)



Followwing up from p.b-t:

See the following two images.
Both images are exactly the same, except the second has a visible light
source (i.e., high ambient sphere)
material:

  material{
    texture{
      pigment{rgb <0,0,1>}
      finish{
        conserve_energy
        ambient 0
        diffuse 0
        reflection {
          0 1
          fresnel on
        }
      }
    interior{
      ior 1.1335
    }
  }


You can see a round spot in the middle of the sphere at which the reflection
fading stops completely and there is no more reflection.
In the second image, I used a high ambient sphere that would reflect
slightly larger than the spot.  Now you can see the black spot very clearly.
I do understand about colour clipping but I don't think this is applicable
here. I just wanted to know if it is a limitation of number accuracy or if
is intended to act that way (i.e., ignore reflection fading below a certain
threshold) and if this is the case is there a way to alter this threshold?

-tgq

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Attachments:
Download 'VR1.jpg' (35 KB) Download 'VR2.jpg' (36 KB)

Preview of image 'VR1.jpg'

Preview of image 'VR2.jpg'

"Trevor Quayle" <Tin### [at] hotmailcom> wrote in message
news:3bd05a6b@news.povray.org...
> Both images are exactly the same, except the second has a visible light
> source (i.e., high ambient sphere)
> material:
>
>   material{
>     texture{
>       pigment{rgb <0,0,1>}
>       finish{
>         conserve_energy
>         ambient 0
>         diffuse 0
>         reflection {
>           0 1
>           fresnel on // fresnel on yet no transparency used??
>         }
>       }
     } // missed a brace here
>     interior{
>       ior 1.1335
>     }
>   }
>
>
> You can see a round spot in the middle of the sphere at which the
reflection
> fading stops completely and there is no more reflection.
> In the second image, I used a high ambient sphere that would reflect
> slightly larger than the spot.  Now you can see the black spot very
clearly.
> I do understand about colour clipping but I don't think this is applicable
> here. I just wanted to know if it is a limitation of number accuracy or if
> is intended to act that way (i.e., ignore reflection fading below a
certain
> threshold) and if this is the case is there a way to alter this threshold?

I tried this myself and saw only a smooth fade-out into the center of the
reflection, no global settings changes made such as max trace or adc bailout
needed.

Bob H.

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