Hi. As the title indicates, I'm having trouble in my latest hallway scene in
seeing my media. I basically took away reflections for now, removed all
lights, and tossed in a

box {-<75,10,250>,<75,50,250> hollow pigment {rgbf 1} interior {media
{intervals 20 samples 2,10 scattering {2, rgb 0.0001*<1,.75,.25> extinction
.1} confidence 0.9999 variance 1/1000 ratio 0.9}}}

with new lights, such as:

light_source {< 15,12,0> 1 spotlight point_at  0 radius 20 falloff 30
tightness 20 media_interaction on}

OK, great, I get my light shining in through the window and all is nice,
buuut... I get no dust in the air through which the lights shine. If I
increase the rgb value of the scattering, things just get darker in the
spots without spotlights. What do I do?

PS: Yes, Mike, I would be using your MiniPatch, but I am currently using UV
mapping, which is not available in the SuperPatch. :(

Post a reply to this message

On Mon, 11 Oct 1999 14:23:40 -0400, TonyB wrote:

>PS: Yes, Mike, I would be using your MiniPatch, but I am currently using UV
>mapping, which is not available in the SuperPatch. :(

UV mapping is.  Photon mapping isn't yet.

Post a reply to this message

TonyB wrote:
> 
> Hi. As the title indicates, I'm having trouble in my latest hallway scene in
> seeing my media. I basically took away reflections for now, removed all
> lights, and tossed in a
> 
> box {-<75,10,250>,<75,50,250> hollow pigment {rgbf 1} interior {media
> {intervals 20 samples 2,10 scattering {2, rgb 0.0001*<1,.75,.25> extinction
> .1} confidence 0.9999 variance 1/1000 ratio 0.9}}}
> 
> with new lights, such as:
> 
> light_source {< 15,12,0> 1 spotlight point_at  0 radius 20 falloff 30
> tightness 20 media_interaction on}
> 
> OK, great, I get my light shining in through the window and all is nice,
> buuut... I get no dust in the air through which the lights shine. If I
> increase the rgb value of the scattering, things just get darker in the
> spots without spotlights. What do I do?
> 
> PS: Yes, Mike, I would be using your MiniPatch, but I am currently using UV
> mapping, which is not available in the SuperPatch. :(

 I have run into problems myself when trying to produce a scene with media
where the camera is inside of the container. It does not work the same way
as if your camera is outside the container when using media inside an
interior statement.

  Try a simple scattering media instead. I have been playing with the code
below lately and have had pretty good results. The settings here might be
a little grainier than you want but can easily be adjusted to give a finer
"dust" if you so desire. Just make sure that you still specify hollow on
your box so that the media will enter it.

media {
scattering {1, .1 extinction .25}
//method 1
//jitter .5
samples 15, 51
intervals 14
ratio .99
confidence .999
variance 1/10
}  

 I have also just recently found that adding a black media along with your
reactive media can speed up render times when using a scattering media. I
have no concrete evidence to support this claim but if you try my above code
try also adding this along with it to see how it compares time wise:

media {
scattering {1, 0 extinction .15}
//method 2
samples 10, 51
intervals 15
ratio .99
confidence .999
variance 1/10
} 

I intentionaly use slightly different sampling and intervals to avoid
cancellation effects. It may make no difference but why mess with it
if it works... I may also be completely daft :)


-- 
Ken Tyler -  1100+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

Post a reply to this message

>UV mapping is.  Photon mapping isn't yet.



malditos documentos! Mira lo que me has hecho, pasar pena! Maldita sea!)</to
self>

Post a reply to this message

> I have run into problems myself when trying to produce a scene with media
>where the camera is inside of the container. It does not work the same way
>as if your camera is outside the container when using media inside an
>interior statement.

Perhaps if I were to difference the box with a small sphere around the
camera... nah...

>  Try a simple scattering media instead. I have been playing with the code
>below lately and have had pretty good results. The settings here might be
>a little grainier than you want but can easily be adjusted to give a finer
>"dust" if you so desire. Just make sure that you still specify hollow on
>your box so that the media will enter it.


Thanks.

> I have also just recently found that adding a black media along with your
>reactive media can speed up render times when using a scattering media. I
>have no concrete evidence to support this claim but if you try my above
code
>try also adding this along with it to see how it compares time wise:


Odd, but cool. What made you try this?

>I intentionaly use slightly different sampling and intervals to avoid
>cancellation effects. It may make no difference but why mess with it
>if it works... I may also be completely daft :)


Nah, you were written by the finest Arcturian programmers. ;)

Post a reply to this message

TonyB wrote:

> > I have also just recently found that adding a black media along with your
> >reactive media can speed up render times when using a scattering media. I
> >have no concrete evidence to support this claim but if you try my above
> code
> >try also adding this along with it to see how it compares time wise:
> 
> Odd, but cool. What made you try this?

I was trying to find a shorter route to India. No wait that was Columbus.

Er... um... I was trying to thin out the media in my scene. It was a little
too dense for my needs and I thought strangly enough that adding a black
media might help. Well it didn't do anything to the density of the media
im my scene but the increase in render time was instantly noticable.

Go figure !

 
> >I intentionaly use slightly different sampling and intervals to avoid
> >cancellation effects. It may make no difference but why mess with it
> >if it works... I may also be completely daft :)
> 
> Nah, you were written by the finest Arcturian programmers. ;)

:)

-- 
Ken Tyler -  1100+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

Post a reply to this message

P.S. Let me know how things turn out for you. I am curious if my advice
     and observations on this are correct for your circumstances and if
     you too notice any difference with and without the black media.

-- 
Ken Tyler -  1100+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

Post a reply to this message

>P.S. Let me know how things turn out for you. I am curious if my advice
>     and observations on this are correct for your circumstances and if
>     you too notice any difference with and without the black media.


The extra media seems to slow it down for me. :( I've achieved the effect I
was after, but now I have another problem. The media looks fine in the
foreground, but towards the back it becomes totally white (denser I guess).
I'm experimenting as I write...

Post a reply to this message

Try increasing the rgb value of the scattering and lowering the extinction.
It works for me.
  (Actually my computer is rendering an animation of a moving light source
and media which I'll probably post soon in p.b.animations; the media looks
just great).

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

Post a reply to this message