Build simple scene:
camera + two lightsources + media (without container)

You get:
Black image.

Or just use one fading lightsource, same result.

Anything one should consider when building conatiner-less media?

Using RC3, Win98, 512MB RAM, 1.4GHZ Athlon

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

Post a reply to this message

Hm. Noticed though that multiple spotlights work...

Tim Nikias wrote:

> Build simple scene:
> camera + two lightsources + media (without container)
>
> You get:
> Black image.
>
> Or just use one fading lightsource, same result.
>
> Anything one should consider when building conatiner-less media?
>
> Using RC3, Win98, 512MB RAM, 1.4GHZ Athlon

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

Post a reply to this message

On Mon, 06 May 2002 19:07:58 +0200, Tim Nikias wrote:
> Hm. Noticed though that multiple spotlights work...
> 

Have you tried rendering the example scenes, media1.pov and media2.pov
I get a partial image with media1 and a black image with media2 here
on my Linux system (as reported above). 

-- 
sphere{z*5,1pigment{rgb.5}finish{reflection.3specular.5}}box{<-50,-3,-50>
<50,-2,50>pigment{checker/*\__\\__/  * \_\\__*/scale 2}finish{ambient.7}}
light_source/*__\\__\\__\\__\\__\(    ~ )\__\\__\\__\\__\\*/{<2,5,1>*4,1} 
/*\\__\\__\\__\\__\\__\\__\\__\\__\~  -/__\\__\\__\\__\\__\\*//* Steve */

Post a reply to this message

Nope, but they are rendering fine.

I've got no clue, what the actual problem is.
Using something different than spotlights perhaps?

Steve wrote:

> On Mon, 06 May 2002 19:07:58 +0200, Tim Nikias wrote:
> > Hm. Noticed though that multiple spotlights work...
> >
>
> Have you tried rendering the example scenes, media1.pov and media2.pov
> I get a partial image with media1 and a black image with media2 here
> on my Linux system (as reported above).
>
> --
> sphere{z*5,1pigment{rgb.5}finish{reflection.3specular.5}}box{<-50,-3,-50>
> <50,-2,50>pigment{checker/*\__\\__/  * \_\\__*/scale 2}finish{ambient.7}}
> light_source/*__\\__\\__\\__\\__\(    ~ )\__\\__\\__\\__\\*/{<2,5,1>*4,1}
> /*\\__\\__\\__\\__\\__\\__\\__\\__\~  -/__\\__\\__\\__\\__\\*//* Steve */

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

Post a reply to this message

Tim Nikias <tim### [at] gmxde> wrote:
> Build simple scene:
> camera + two lightsources + media (without container)

> You get:
> Black image.

  Correct behaviour.
  Perhaps not the desired behaviour, but the expected one.
  The problem is that POV-Ray can't sample media along an infinitely long
ray. There's just no way it can do that. The ray must be finite in order
to be possible to sample. This means that sampling media is only possible
for rays that hit an object.
  Another way of being able to sample media is using spotlights because also
in this case the ray is not infinite (it is sampled only inside the spotlight
cone).

-- 
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -

Post a reply to this message

Ah. Perhaps a note in the docs would be fitting?

Warp wrote:

> Tim Nikias <tim### [at] gmxde> wrote:
> > Build simple scene:
> > camera + two lightsources + media (without container)
>
> > You get:
> > Black image.
>
>   Correct behaviour.
>   Perhaps not the desired behaviour, but the expected one.
>   The problem is that POV-Ray can't sample media along an infinitely long
> ray. There's just no way it can do that. The ray must be finite in order
> to be possible to sample. This means that sampling media is only possible
> for rays that hit an object.
>   Another way of being able to sample media is using spotlights because also
> in this case the ray is not infinite (it is sampled only inside the spotlight
> cone).
>
> --
> #macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
> N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
> N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

Post a reply to this message

On Tue, 07 May 2002 06:37:41 +0200, Tim Nikias <tim### [at] gmxde>
wrote:

>Ah. Perhaps a note in the docs would be fitting?

Look up the 'ratio' keyword under media.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg

Post a reply to this message