Sorry, I should've been more clear - I'm actually just using a real sphere 
with various lighting effecets to light my scene - so whilst it is 
technically a sky sphere, it's not done the way POV usually would - I'm 
trying to get a natural lighting effect (as per a seminar I saw by Paul 
Debevec). Results have been quite good (I've posted a vid in p.b.a if you're 
interested)

The Sky declaration is:

 union{
  sphere{0,5
   hollow no_shadow
   texture{
    pigment{
     function{fp(x,y,z).gray}
     poly_wave light_exponent
     color_map{
     [0.0 rgb 0]
     [1.0 rgb light_ambient]
     }
    }
  finish { ambient light_ambient diffuse 0 }
   }
  }
  sphere{0,4.999
   hollow no_shadow
   texture{
    pigment{p_image_filtered}
  finish { ambient light_ambient diffuse 0 }
   }
  }
 }

(I hasten to add that this is not my code - I grabbed it online. Am not 100% 
sure where from but will find it if anyone wants to know)

Thanks for any help you can give Stephen :)

-Simon

"Stephen" <mcavoysATaolDOTcom@> wrote in message 
news:5iaj539kp36u1urgbqo3th2pgbv7lf2u5a@4ax.com...
> On Sun, 27 May 2007 14:41:24 +0100, "Simon" <povray@*NOSPAM*SOWare.co.uk> 
> wrote:
>
>>It's working (ish) with the objects. I have a sky sphere and want to fade
>>that too....
>
> I've never obtained satisfactory results when trying to fade an object. So 
> I
> might not be the best person to help you further. :-(
> But I've just checked this and it looks like Pov can only use one 
> sky_sphere.
> The last in the scene is the one it uses.
>
> Regards
> Stephen

Post a reply to this message

> The Sky declaration is:
> 
>  union{
>   sphere{0,5
>    hollow no_shadow
>    texture{
>     pigment{
>      function{fp(x,y,z).gray}
>      poly_wave light_exponent
>      color_map{
>      [0.0 rgb 0]
>      [1.0 rgb light_ambient]
>      }
>     }
>   finish { ambient light_ambient diffuse 0 }
>    }
>   }
>   sphere{0,4.999
>    hollow no_shadow
>    texture{
>     pigment{p_image_filtered}
>   finish { ambient light_ambient diffuse 0 }
>    }
>   }
>  }

Have the inner sphere become increasingly transparent to reveal the 
outer sphere.

If p_image_filtered is a texture declared in Pov, you can add change the 
transmit value of the colors as mentioned earlier in the thread.

If it's an image, you can use the transmit bitmap modifier, described here:
http://povray.org/documentation/view/3.6.1/337/

(While I was looking that up, I accidentally ran across the 
interior_texture option. I didn't know about that--it looks really useful!)

-- 
William Tracy
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You know you've been raytracing too long when you actually contemplate 
spending $$$ at a printing bureau to litho some of your raytraces for 
your non-computer-literate relatives.
George Erhard

Post a reply to this message

"William Tracy" <wtr### [at] calpolyedu> wrote in message 
news:465a1a93$1@news.povray.org...
> If it's an image, you can use the transmit bitmap modifier, described 
> here:
> http://povray.org/documentation/view/3.6.1/337/

Thanks so much, that was exactly what I was looking for! Between you and 
Stephen, I've got my answer. Thank you all so much!

Post a reply to this message

"Warp" <war### [at] tagpovrayorg> wrote in message 
news:46597085@news.povray.org...
>  A completely transparent interior_texture might be worth a try if you
> want to make the inner sides invisible.
Thanks for that Warp, I was getting a problem where: If the object passed 
behind itself while transparent, It is visible even is the transparency 
should be 100% - I think this may fix it...

Thanks again,
S

Post a reply to this message

Simon <povray@*nospam*soware.co.uk> wrote:
> Thanks for that Warp, I was getting a problem where: If the object passed 
> behind itself while transparent, It is visible even is the transparency 
> should be 100% - I think this may fix it...

  That may have more to do with max_trace_level.

-- 
                                                          - Warp

Post a reply to this message

(excuse me while I go kick myself a few times)

It may well do. I reduced max_trace so I could get some test renderings done 
with positioning - and never set it back up before moving on. As I've never 
used transparency before, I assumed I was making a mistake there.

Thanks Warp.

"Warp" <war### [at] tagpovrayorg> wrote in message 
news:465ad45f@news.povray.org...
> Simon <povray@*nospam*soware.co.uk> wrote:
>> Thanks for that Warp, I was getting a problem where: If the object passed
>> behind itself while transparent, It is visible even is the transparency
>> should be 100% - I think this may fix it...
>
>  That may have more to do with max_trace_level.
>
> -- 
>                                                          - Warp

Post a reply to this message

Simon wrote:
> (excuse me while I go kick myself a few times)
> 
> It may well do. I reduced max_trace so I could get some test renderings done 
> with positioning - and never set it back up before moving on. As I've never 
> used transparency before, I assumed I was making a mistake there.

I've certainly made max_trace_level mistakes myself.

I remember posting one image here with the comment that I might need to 
go back and make some of the shapes slightly lighter and less opaque. 
Someone pointed out that had nothing to do with it--it was 
max_trace_level. :-P

-- 
William Tracy
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You know you've been raytracing too long when you've tried rendering 
hair with each strand as an object.
Quietly Watching

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